Document ID: EPA-HQ-OW-2015-0804-0176
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2016-04-20T04:00Z

Economic Analysis for Proposal of Certain Federal Water Quality Standards Applicable to Maine 
                                                
                                                
                                                
                                                Contract # EP-BPA-13-W-0001
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                
                                                March 24, 2016
                                                
                                                                               
                                                
                                                
                                                Prepared for:
                                                United States Environmental Protection Agency
                                                Region 1
                                                5 Post Office Square, Suite 100 (OEP06-2)
                                                Boston, MA 02109
                                                
                                                
                                                
                                                Submitted by:
                                                Abt Associates 
                                                55 Wheeler Street
Cambridge, MA 02138
                                                
                                                
                                                Under Subcontract to:
                                                WaterVision LLC

Executive Summary
The United States Environmental Protection Agency (EPA) is proposing water quality standards (WQS) applicable to waters under jurisdiction of the State of Maine. The proposal addresses EPA's disapproval of many of the state's human health criteria (HHC) and six other criteria for waters in Indian lands, as well as the disapproval of three criteria and standards affecting all state waters. The proposal also addresses an Administrator's determination that many of Maine's HHC are not adequate to protect the designated use of sustenance fishing.
Although the proposed rule does not establish any requirements directly applicable to regulated entities or other sources of pollution, state implementation may result in new or revised Maine Pollutant Discharge Elimination System (MEPDES) permit conditions for point source dischargers and additional controls on nonpoint sources of pollutant loadings. This report provides estimates of the potential incremental compliance actions and costs that may be associated with the proposed regulation. 
The analysis focuses on the costs only and does not quantify benefits that may result from the proposed WQS, including for example, avoided adverse health impacts and associated costs from cleaner waters and positive impacts to the tourism, fishing, or shellfishing industries. 
EPA used available data from water quality assessments, permit fact sheets, priority pollutant scans, and other sources to evaluate the potential effects of, and resultant costs of the action. Based on the available information, EPA determined that the proposed criteria for pH and temperature (for waters in Indian lands), proposed criteria for dissolved oxygen (DO) (for all Class A state waters) and proposed criteria for phenol (for waters outside of Indian lands) are unlikely to result in incremental costs to point sources. EPA estimated the potential costs to point sources resulting from proposed HHC, bacteria criteria, ammonia criteria, and mixing zone policy for waters in Indian lands. Exhibit E- 1 summarizes these costs. 
Low-cost pollution prevention (P2) strategies would result in far lower costs than end-of-pipe treatment, which would be used only if less expensive approaches were unsuccessful. Total annualized costs range from $213,000 if lower-cost options are effective to a worst-case estimate of $1 million if end-of-pipe treatment is needed. EPA notes that these annual costs are well below the threshold of $100 million that triggers more extensive economic analysis (e.g., a complete benefit-cost analysis) under Executive Orders 12866 and 13563.
Exhibit E- 1. Summary of Estimated Costs for the Proposed Rule[1]
Proposed WQS
Annualized Costs 
(thousands; 2014$)[2]
Human health criteria for waters in Indian lands 
$28 
                                       
$43
Bacteria criteria for waters in Indian lands
$185
                                       
$705
Mixing zone policy for waters in Indian lands
Not estimated
                                       
$273
Total[3]
$213 
                                       
$1,021
1. Excludes costs for proposed ammonia criteria, for which EPA expects costs to be zero. See Section 4.3.
2. Except as otherwise noted (see Section 4.4 for assumptions regarding expected useful life of cooling towers), one-time costs are annualized over 20 years using a 3 percent discount rate. See Appendix E for results using a 7 percent discount rate.
3. Lower bound of total costs excludes costs associated with mixing zone policy for which EPA estimated only the upper bound scenario. See Section 4.4 for details.

While the analysis of costs generally follows the approach a permit writer would use to evaluate and set discharge permit conditions, reliance on available data involves uncertainty and limitations not present during actual permit development, when the permit writer may have access to and incorporate more site-specific data (e.g., ambient water quality samples, priority pollutant scans using lower detection limits). See Section 6.3 for further discussion of the uncertainty associated with the use of existing data.

Contents
Executive Summary	ii
Contents	i
Exhibits	v
List of Abbreviations	viii
1	Introduction	1
1.1	Background	1
1.2	Purpose and Scope of the Analysis	4
1.2.1	Proposed WQS Applicable only to Waters in Indian Lands	5
1.2.2	Proposed Criteria Applicable to All State Waters (DO) and to Waters Outside of Indian Lands (Phenol)	6
1.3	Organization of Report	7
2	Baseline for the Analysis	9
2.1	Sources of Pollutants to Surface Waters	9
2.1.1	Municipal and Industrial Dischargers	9
2.1.2	Urban Stormwater	10
2.1.3	Onsite Wastewater Disposal Systems	11
2.1.4	Agriculture and Forestry	12
2.1.5	Atmospheric Deposition	12
2.1.6	Contaminated Sediments	13
2.2	Baseline Water Quality and Criteria	13
2.2.1	Water Quality Impairments	13
2.2.2	Toxics	15
2.2.3	Bacteria	19
2.2.4	Ammonia	20
2.2.5	pH	21
2.2.6	Tidal Temperature	21
2.2.7	Mixing Zone	21
2.2.8	Dissolved Oxygen	22
3	Proposed Criteria	24
3.1	Proposed Criteria for Waters in Indian Lands	24
3.1.1	Human Health Criteria	24
3.1.2	Bacteria	28
3.1.3	Ammonia	31
3.1.4	pH	34
3.1.5	Temperature Criterion for Tidal Waters	34
3.1.6	Mixing Zone	35
3.2	Proposed Dissolved Oxygen Criteria for All State Waters	37
3.3	Proposed Phenol Criteria for State Waters Outside of Indian Lands	38
4	Method for Estimating Potential Costs: Point Sources	40
4.1	Costs from Proposed Human Health Criteria for Waters in Indian Lands	40
4.1.1	Dischargers to Waters in Indian Lands or Tributaries	41
4.1.2	Reasonable Potential Analysis	43
4.1.3	Projecting Effluent Limitations	48
4.1.4	Identifying Compliance Scenarios and Costs	49
4.2	Costs from Proposed Bacteria Criteria for Waters in Indian Lands	53
4.3	Costs from Proposed Ammonia Criteria for Waters in Indian Lands	55
4.4	Costs from the Proposed Mixing Zone Policy	58
5	Methods for Identifying Potential Costs: Nonpoint Sources	60
5.1	Identifying Exceedances	60
5.2	Identifying Compliance Actions and Costs	60
6	Potential Compliance Costs	62
6.1	Point Sources	62
6.2	Nonpoint Sources	64
6.3	Uncertainties and Quality Assurance	64
7	References	67
A	Facility-level Analyses of Implication of Proposed Human Health and Ammonia Criteria	70
A.1	Baileyville POTW	70
A.1.1	Effluent Data	70
A.1.2	Reasonable Potential Analysis	71
A.2	Brownville	72
A.3	Calais POTW	72
A.3.1	Effluent Data	73
A.3.2	Reasonable Potential Analysis	73
A.4	Calais School	74
A.5	Cobb State Fish Hatchery	74
A.6	Covanta Maine	75
A.7	Dolby Hydro Project	75
A.8	Dover-Foxcroft Water District	75
A.9	Dover-Foxcroft WWTP	76
A.9.1	Effluent Data	76
A.9.2	Reasonable Potential Analysis	76
A.10	East Millinocket Hydro Project	78
A.11	East Millinocket POTW	78
A.12	Eustis Hydro Project	78
A.13	Grand Lake Stream Fish Hatchery	79
A.14	Guilford-Sangerville WWTF	79
A.14.1	Effluent Data	80
A.14.2	Reasonable Potential Analysis	80
A.15	Houlton Water Company POTW	81
A.15.1	Effluent Data	81
A.15.2	Reasonable Potential Analysis	82
A.16	Howland Hydro	83
A.17	Howland POTW	83
A.17.1	Effluent Data	83
A.17.2	Reasonable Potential Analysis	83
A.18	Lincoln Sanitary District	84
A.18.1	Effluent Data	85
A.18.2	Reasonable Potential Analysis	85
A.19	Mattaceunk Hydro Project	86
A.20	Mattawamkeag WWTF	86
A.21	Milford	86
A.22	Millinocket Hydro	87
A.23	Millinocket POTW	87
A.23.1	Effluent Data	87
A.23.2	Reasonable Potential Analysis	87
A.24	Milo POTW	88
A.24.1	Effluent Data	88
A.24.2	Reasonable Potential Analysis	89
A.25	Passamaquoddy POTW	90
A.26	Passamaquoddy Water District	90
A.27	Penobscot Indian Nation	90
A.27.1	Effluent Data	90
A.27.2	Reasonable Potential Analysis	91
A.28	Tate and Lyle Ingredients	91
A.28.1	Effluent Data	92
A.28.2	Reasonable Potential Analysis	92
A.28.3	Effluent Limitations	93
A.28.4	Compliance Costs	94
A.29	Washington County Community College	97
A.30	West Enfield Hydro	97
A.31	Woodland Hydro	97
A.32	Woodland Pulp	98
A.32.1	Effluent Data	98
A.32.2	Reasonable Potential Analysis	98
A.33	Woodland Pulp: North Site	99
B	Derivation of Mercury Water Column Concentration for Use in Evaluating Reasonable Potential	100
C	Estimated Flows for Selected Receiving Waters in Indian Lands	102
C.1	Harmonic Mean Flow	102
C.2	Dissolved Concentration Potential	102
D	Review of pH Limitations in Existing Permits and Cost Potential	104
D.1	Calais POTW	104
D.2	Guilford-Sangerville	104
D.3	Houlton WWTF	105
D.4	Lincoln Sanitary District	105
D.5	Tate and Lyle	105
D.6	Woodland Pulp	106
E	Potential Point Source Compliance Costs, 7% Discount Rate	107

Exhibits
Exhibit E- 1. Summary of Estimated Costs for the Proposed Rule[1]	iii
Exhibit 1-1. EPA Disapprovals of Maine WQS and Proposed WQS	3
Exhibit 1-2: Indian lands in Maine and location of facilities with permits to discharge to waters in Indian lands or tributaries.	6
Exhibit 1-3. Document Roadmap for Analysis of Effects and Costs of EPA Proposed Rules in Response to EPA Disapprovals[1]	8
Exhibit 2-1. Number of Dischargers in Maine, by Category	9
Exhibit 2-2. Cumulative Size of Impaired Waters by Listing Cause/Stressor Type	14
Exhibit 2-3. Baseline Water Quality Criteria for Toxic Priority Pollutants in Maine[1]	16
Exhibit 3-1. Proposed Human Health Criteria for the Consumption of Water and Organisms and Organisms Only (ug/L)	24
Exhibit 3-2. Baseline and Proposed Bacteria Criteria	30
Exhibit 3-3. Comparison of Maine's baseline (solid line) and EPA's proposed (dashed lines) ammonia acute criteria for different temperatures[1]	32
Exhibit 3-4. Comparison of Maine's baseline (solid lines) and EPA's proposed (dashed lines) ammonia chronic criteria for different water temperatures.	33
Exhibit 3-5. Discharger with Thermal Mixing Zone Affecting Waters in Indian Lands	37
Exhibit 4-1. Summary of Dischargers to Waters in Indian Lands or Their Tributaries	41
Exhibit 4-2: Facilities discharging to the Penobscot River in Indian lands or its tributaries.	46
Exhibit 4-3. Summary of Dischargers with Detected Effluent Data and Reasonable Potential Analysis	47
Exhibit 4-4. Summary of Current Disinfection and Dechlorination Practices at Facilities with Bacteria Limitations	53
Exhibit 4-5. Summary of Ammonia Effluent Data	56
Exhibit 4-6. Summary of Ammonia Reasonable Potential Analysis	57
Exhibit 4-7. Estimates of Cooling Tower Retrofit Costs at Facility with Thermal Mixing Zone for Discharges to Waters in Indian Lands or Tributaries	59
Exhibit 6-1. Summary of Estimated Compliance Costs for Proposed Human Health Criteria for Waters in Indian Lands[1]	62
Exhibit 6-2. Summary of Estimated Compliance Costs for Proposed Criteria for Bacteria[1]	63
Exhibit 6-3. Summary of Upper Bound Estimated of Compliance Costs for Proposed Mixing Zone Policy[1]	63
Exhibit 6-4. Summary of Estimated Point Source Compliance Costs[1]	64
Exhibit 6-5. Uncertainties in Analysis of Costs	65
Exhibit A-1. Summary of Effluent Data: Baileyville POTW	71
Exhibit A-2. Mercury Load Allocation for St. Croix River and Passamaquoddy Bay	71
Exhibit A-3. Reasonable Potential Analysis for Baileyville POTW	72
Exhibit A-4. Summary of Effluent Data: Calais POTW	73
Exhibit A-5. Reasonable Potential Analysis for Calais POTW	74
Exhibit A-6. Outfall Data for Covanta Maine Facility[1]	75
Exhibit A-7. Summary of Effluent Data: Dover-Foxcroft WWTP	76
Exhibit A-8. Mercury Load Allocation for Penobscot River (Piscataquis Confluence)	77
Exhibit A-9. Mercury Load Allocation for Penobscot River, Downstream	77
Exhibit A-10. Reasonable Potential Analysis for Dover-Foxcroft WWTP	78
Exhibit A-11. Summary of Flow and Limitation Tiers: Guilford-Sangerville WWTF[1]	79
Exhibit A-12. Summary of Effluent Data: Guilford-Sangerville WWTF	80
Exhibit A-13. Reasonable Potential Analysis for Guilford-Sangerville WWTF	81
Exhibit A-14. Summary of Effluent Data: Houlton POTW	81
Exhibit A-15. Mercury Load Allocation for Meduxnekeag River	82
Exhibit A-16. Reasonable Potential Analysis for Houlton POTW	82
Exhibit A-17. Summary of Effluent Data: Howland POTW	83
Exhibit A-18. Mercury Load Allocation for Penobscot River at Howland POTW	84
Exhibit A-19. Reasonable Potential Analysis for Howland POTW	84
Exhibit A-20. Summary of Effluent Data: Lincoln Sanitary District	85
Exhibit A-21. Mercury Load Allocation for Penobscot River at Lincoln Sanitary District	85
Exhibit A-22. Reasonable Potential Analysis for Lincoln Sanitary District	86
Exhibit A-23. Summary of Effluent Data: Millinocket POTW	87
Exhibit A-24. Reasonable Potential Analysis for Millinocket POTW	88
Exhibit A-25. Summary of Effluent Data: Milo POTW	89
Exhibit A-26. Reasonable Potential Analysis for Milo POTW	89
Exhibit A-27. Summary of Effluent Data: Penobscot Indian Nation	91
Exhibit A-28. Reasonable Potential Analysis for Penobscot Indian Nation	91
Exhibit A-29. Summary of Effluent Data: Tate and Lyle	92
Exhibit A-30. Reasonable Potential Analysis for Tate and Lyle Ingredients	93
Exhibit A-31. Load Allocation for Tate and Lyle Ingredients	93
Exhibit A-32. Effluent Limitations for Tate and Lyle Ingredients	94
Exhibit A-33. Input Parameters Used to Estimate Granular Activated Carbon Treatment Costs for Tate and Lyle Ingredients	95
Exhibit A-34. Range of Compliance Costs for Bis(2-ethylhexyl)phthalate for Tate and Lyle Ingredients	96
Exhibit A-35. Summary of Effluent Data: Woodland Pulp	98
Exhibit A-36. Reasonable Potential Analysis for Woodland Pulp	99
Exhibit C- 1. Flow Statistics for Selected Receiving Waters in Indian Lands.	102
Exhibit E-1. Summary of Estimated Compliance Costs for Proposed Human Health Criteria for Waters in Indian Lands[1]	107
Exhibit E-2. Summary of Estimated Compliance Costs for Proposed Criteria for Bacteria[1]	107
Exhibit E-3. Summary of Upper Bound Estimated of Compliance Costs for Proposed Mixing Zone Policy[1]	108
Exhibit E-4. Summary of Estimated Point Source Compliance Costs[1]	108

List of Abbreviations
AMEL			Average monthly effluent limitation
BMP			Best management practice
CCC			Criterion continuous concentration
CMC			Criterion maximum concentration
CPI			Consumer Price Index
CWA		 	Clean Water Act
DCP			Dissolved concentration potential
DDT			Dichlorodiphenyltrichloroethane
DMR			Discharge monitoring report
DO				Dissolved oxygen
ENR CCI		Engineering News-Record construction cost index
EPA			United States Environmental Protection Agency
FCR			Fish consumption rate
GAC			Granular activated carbon
GDP-IPD 		Gross Domestic Product implicit price deflator
HHC			Human health criteria
I&I				Inflow and infiltration
ICIS			Integrated Compliance Information System
LID			Low impact development
MDIFW		Maine Department of Inland Fisheries and Wildlife
MEDEA		Maine Division of Environmental and Assessment
MEDEH		Maine Division of Environmental Health
MEC			Maximum effluent concentration
MEDEP		Maine Department of Environmental Protection
MEPDES		Maine Pollutant Discharge Elimination System
MPN			Most probable number
MS4			Municipal separate storm sewer systems
NOI			Notice of intent
NPDES		National Pollutant Discharge Elimination System
O&M			Operation and Maintenance
OSDS			Onsite Wastewater Disposal Systems
P2				Pollution prevention
PCB			Polychlorinated biphenyl
POTW			Publicly owned treatment works
PPI				Producer Price Index
Ppm			parts per million
SIC			Standard industrial classification
SU				Standard units
SWMP			Stormwater management program
TMDL			Total maximum daily load
WDL			Waste Discharge License
WQBELs		Water quality based effluent limitations
WQS			Water quality standards
WWTF		Wastewater treatment facility
ZID			Zone of initial dilution
Introduction
The United States Environmental Protection Agency (EPA) is proposing water quality standards (WQS) applicable to waters under jurisdiction of the State of Maine. The proposal addresses EPA's disapproval of many of the state's human health criteria (HHC) and six other criteria for waters in Indian lands, as well as the disapproval of three criteria and standards affecting all state waters. The proposal also addresses an Administrator's determination that many of Maine's HHC are not adequate to protect the designated use of sustenance fishing. This report provides estimates of the potential incremental compliance actions and costs that may be associated with the proposed regulations.
For the purposes of this report, the term "waters in Indian lands" refers to waters in the reservations and trust lands of the four Indian tribes in Maine, as described more fully in the preamble to the proposed rule and in EPA's Technical Support Document, entitled "Scope of Waters"; and "discharges to waters in Indian lands and their tributaries" refers to discharges directly into waters in Indian lands, discharges indirectly to such waters where the point of discharge is upstream of the boundary of the Indian lands, and discharges to the tributaries of such waters. 
Background
The Federal Water Pollution Control Act (as amended through P.L. 107 - 303, November 27, 2002), also known as the Clean Water Act (CWA), sets the basic structure for regulating pollutant discharges into the waters of the United States. In the CWA, Congress established the national objective to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters," and to achieve "wherever attainable, an interim goal of water quality which provides for the protection and propagation of fish, shellfish, and wildlife and for recreation in and on the water" (CWA sections 101(a) and 101(a)(2)).
The CWA establishes the basis for the current WQS regulation and program. CWA section 303 addresses the development of state and authorized tribal WQS. WQS reflect the CWA national objectives for each water body. The core components of these standards are designated uses, water quality criteria, and antidegradation requirements. Designated uses establish the environmental objectives for a water body, while water quality criteria define the conditions necessary to achieve those environmental objectives. The antidegradation program complements designated uses and criteria by providing a framework for maintaining and protecting water quality.
After states, authorized tribes, territories, and the District of Columbia (hereafter, states and authorized tribes) designate the uses of waters under their jurisdiction, they must establish water quality criteria that protect those designated uses. EPA's regulation at §131.11(a)(1) provides that such criteria "must be based on sound scientific rationale, and must contain sufficient parameters or constituents to protect the designated use." States and authorized tribes must also adopt antidegradation policies to protect and maintain high quality waters and existing uses of all waters, and identify specific methods to implement those policies (§131.12).
Any new or revised WQS adopted by a state under CWA section 303(c) must be submitted to EPA for review, to determine whether it meets the CWA's requirements, and approval or disapproval. If EPA disapproves a state WQS, EPA is required, under CWA section 303(c)(4), to promptly propose federal WQS if the state does not adequately address the disapproval within ninety (90) days after any disapproval. EPA is further required to promulgate a federal standard within ninety days of the proposal unless the state adopts a revised standard that meets the requirements of the CWA. 
CWA section 303(c)(4)(B) authorizes the Administrator to determine, even in the absence of a state submission, that a new or revised standard is necessary to meet CWA requirements. Upon making such a determination, EPA shall promptly propose, and then within ninety days promulgate, any such new or revised standard unless prior to such promulgation, the state has adopted a revised or new WQS which EPA determines to be in accordance with the CWA.
Exhibit 1-1 summarizes the proposed WQS associated with EPA's disapprovals of Maine WQS. Items 1 through 7 in the table apply specifically to waters in Indian lands, whereas Items 8 through 10 apply more broadly to all state waters, unless otherwise specified. In addition, with respect to item 1, EPA proposes the identical HHC to address the Administrator's determination. Several specific proposals described in items 1 through 3, 5 through 7, 9 and 10 of Exhibit 1-1 may result in new or more stringent requirements for permittees or others. This analysis seeks to identify and estimate the potential incremental costs associated with new or more stringent requirements that result from the proposed WQS. 
Other proposed WQS (items 4 and 8 in Exhibit 1-1) relate to state provisions that, as far as EPA is aware, have been rarely, if ever, invoked. Given that they would have been used only in very unusual circumstances, EPA's proposed WQS are therefore expected to have no material impacts and are not addressed further in this report.
Exhibit 1-1. EPA Disapprovals of Maine WQS and Proposed WQS
Disapproval
Current Maine WQS
(M.R.S.)
Proposed WQS[1]
1. Human Health Criteria (HHC) for waters in Indian lands 
M.R.S. § 584, Appendix A
EPA calculated values assuming a fish consumption rate (FCR) of 286 grams per day incorporating new toxicity and exposure parameters for 96 pollutants. 
2. Bacteria Criteria for waters in Indian lands
38 M.R.S §465 (1.B, 2B, 3.B and 4.B), §465-A(1.B), and §465-B(1.B, 2.B and 3.B). For Class B, C, GPA, SB, and SC waters, the criteria apply May 15 to September 30.
The bacteria content of Class AA and Class A waters shall be as naturally occurs, and in Class AA, Class A, Class B, Class C and Class GPA waters, Escherichia coli bacteria shall not exceed a geometric mean of 100 organisms per 100 milliliter (ml) obtained over a representative period of 30 days, nor shall 320 organisms per 100 ml be exceeded more than 10 percent of the time in any 30 day interval. 
The bacteria content of Class SA waters shall be as naturally occurs, and in Class SA, Class SB, and Class SC waters, enterococcus bacteria shall not exceed a geometric mean of 30 organisms per 100 ml obtained over a representative period of 30 days, nor shall 110 organisms per 100 ml be exceeded more than 10 percent of the time in any 30 day interval.
In Class SA shellfish harvesting areas, the number of total coliform bacteria in samples representative of the waters in shellfish harvesting areas shall not exceed a geometric mean for each sampling station of 70 MPN (most probable number) per 100 ml, with not more than ten percent of samples exceeding 230 MPN per 100 ml for the taking of shellfish.
3. Ammonia aquatic life criteria for fresh water in Indian lands
DEP Rule Chapter 584, Appendix A
Tables 5a and 5b in U.S. EPA's Aquatic Life Ambient Water quality Criteria for Ammonia  -  Freshwater (EPA, 2013) provide the acute criteria values and Table 6 provides the chronic criteria. 
4. Natural Conditions Clauses (only as they apply to human health) for waters in Indian lands
38 M.R.S §464(4.C) and 38 M.R.S. §420(2.A)
Proposed rule specifies that these provisions do not apply to HHC (no economic analysis)
5. pH for fresh waters in Indian lands
38 M.R.S §464(4.A(5)) 
Current EPA pH recommendation of 6.5 for lower end of range, and Maine's current 8.5 for upper end.
6. Temperature criteria for tidal waters in Indian lands
DEP Rule Chapter 582(5)
Maximum cumulative increase in weekly average temperature from all artificial sources is 1°C (1.8°F) year round, compared to baseline temperature, and provided that the summer weekly maximum of 18°C (64.4°F) is not exceeded; natural temperature cycles must be maintained. 
7. Mixing zone policy for waters in Indian lands
38 M.R.S §451

Proposed rule clarifies the extent to which criteria may be exceeded in a mixing zone; specifies that mixing zone must be as small as necessary, and pollutant concentrations must be minimized and reflect the best practicable engineering design of the outfall to maximize initial mixing; requires use of methodologies in EPA's "Technical Support Document for Water Quality-based Toxics Control"; prohibits the use of a mixing zone for bioaccumulative pollutants and for bacteria; and establishes a number of restrictions to protect designated uses, including requirements that the mixing zone not result in lethality to organisms passing through or within the mixing zone, and not endanger critical areas such as breeding and spawning grounds, habitat for threatened or endangered species, and areas with sensitive biota, shellfish beds, fisheries, and recreational areas. 
8. Waiver or modification of protection and improvement laws.
38 M.R.S §363-D
Proposed rule specifies that this statute does not allow waivers or modifications of WQS (no economic analysis).
9. Numeric criteria for dissolved oxygen (DO) in Class A waters throughout the State
38 M.R.S §465(2.B)
Includes Maine's year-round criteria of 7 ppm (7 mg/L) or 75 percent of saturation, whichever is higher, and adds more protective DO criteria  --  the 7-day mean DO concentration shall not be less than 9.5 ppm (9.5 mg/L), and the 1-day minimum DO concentration shall not be less than 8 ppm (8.0 mg/L)  --  for spawning areas in winter months. 
10. Phenol criteria for protection of human health (water and organisms) to correct mathematical error, for state waters outside of Indian lands
DEP Rule Chapter 584 Appendix A
4,000 ug/l (based on EPA 304(a) 2015 HHC criteria and Maine's FCR of 32.4 g/day in state waters) (Promulgation for waters in Indian lands addressed in Item 1 above.)
1. Items in italics are expected to have no material effect on dischargers and are therefore not addressed in this economic analysis. 

Purpose and Scope of the Analysis
The purpose of this analysis is to identify, using available water quality and discharge data and information, the incremental compliance actions and costs that publicly owned treatment works (POTWs) and industrial point source dischargers may incur as a result of EPA's proposed criteria, as well as costs that may be associated with actions to control pollution from nonpoint sources or to implement environmental programs. 
Although the proposed rule does not establish any requirements directly applicable to regulated entities or other sources of pollution, state implementation may result in new or revised Maine Pollutant Discharge Elimination System (MEPDES) permit conditions for point source dischargers to incorporate revised water quality based effluent limitations (WQBELs). This analysis of impacts on point sources focuses specifically on the incremental costs that may be incurred by POTWs and industrial point source dischargers as a result of the proposed WQSs. 
The proposed criteria may also result in incremental determinations that waters do not meet WQS, resulting in the waters being added to the list of impaired waters in the state. As such, the Maine Department of Environmental Protection (MEDEP) may need to develop additional total maximum daily loads (TMDLs) for impaired waters. There may also be incremental controls and costs associated with load allocations for nonpoint sources under such TMDLs to attain standards. 
The scope of the analysis depends on the sets of waters relevant to the proposed WQS, either: (1) waters in Indian lands; (2) other state waters, as described below. 
Proposed WQS Applicable only to Waters in Indian Lands
As discussed in the previous section, numerous disapprovals and corresponding proposed criteria and WQS are specific only to waters in Indian lands. EPA identified the relevant waters based on the extent of Indian lands (specifically, the reservation and trust lands) shown in Exhibit 1-2. The data layer used in creating the map in Exhibit 1-2 identifies Indian lands in New England. 
Facilities that discharge into waters in Indian lands or their tributaries could contribute to exceedances of the proposed criteria in these waters and may incur costs as a result. As shown in Exhibit 1-2 and further described in Section 2.1.1, EPA determined that 33 facilities currently have permits to discharge to waters in Indian lands or their tributaries. In evaluating the implications of complying with proposed WQS applicable to these waters, EPA looked specifically for potential changes in permit conditions for these facilities. For example, EPA evaluated data for the 33 permitted dischargers to determine whether they have reasonable potential to cause or contribute to exceedances of the proposed WQS. When reasonable potential exists, EPA estimated revised effluent limits and potential control costs to meet the limits. 
Exhibit 1-2: Indian lands in Maine and location of facilities with permits to discharge to waters in Indian lands or tributaries. 

Proposed Criteria Applicable to All State Waters (DO) and to Waters Outside of Indian Lands (Phenol)
The proposed criteria for DO and phenol may have cost implications for point and nonpoint sources across the State. 
EPA's proposed DO numeric criterion applies statewide to waters categorized as Class A. The proposed rule would retain Maine's year-round criteria, but add more protective DO criteria for spawning areas in winter months.
Approximately 19,500 miles of rivers and streams are categorized in Class A, representing 44 percent of all river and stream miles in the state (MEDEP, 2012). EPA identified 26 facilities that currently discharge to Class A waters and may incur costs associated with more stringent DO. 
The proposed phenol criterion that would apply to waters outside of Indian lands may result in costs to facilities that have phenol in their effluent. 
Organization of Report
The remainder of this report is organized as follows:
Section 2: Baseline for the Analysis  -  describes the current conditions for each pollutant addressed by the disapproval. For example, in the case of the HHC, the section describes applicable toxic criteria and MEDEP procedures for implementing the criteria in MEPDES permits, sources of toxic pollutants to surface waters, water quality impairments from toxic pollutants, and ongoing efforts to reduce and eliminate these impairments. 
Section 3: Proposed Criteria  -  outlines the proposed WQS.
Section 4: Method for Estimating Potential Costs: Point Sources  -  describes the method for estimating compliance costs associated with baseline and proposed criteria for point sources in terms of revisions to MEPDES permits.
Section 5: Method for Identifying Potential Costs: Nonpoint Sources  -  describes the method for identifying potential for incremental impairment and compliance costs associated with baseline and proposed criteria for nonpoint sources.
Section 6: Potential Compliance Costs  -  provides estimates of potential costs to comply with the proposed WQS, and discusses the uncertainties associated with the estimates. 
Section 7: References  -  provides the references used in the analysis. 
Appendices provide data and information on individual facilities, and analyses of potential impacts under the proposed rule.
Exhibit 1-3 lists the proposed actions and indicates the sections of this report where the baseline conditions, proposed WQS, and estimated cost impacts are discussed.
Exhibit 1-3. Document Roadmap for Analysis of Effects and Costs of EPA Proposed Rules in Response to EPA Disapprovals[1]
Disapproval
Analysis Baseline
Effects of Proposed WQS
Incremental Cost Estimate
1. HHC for waters in Indian lands
Section 2.2.2
Section 3.1.1
Sections 4.1 and 6.1
2. Bacteria criteria for waters in Indian lands
Section 2.2.3
Section 3.1.2
Sections 4.2 and 6.1
3. Ammonia aquatic life criteria for fresh water in Indian lands
Section 2.2.4
Section 3.1.3
Section 4.3; no incremental costs
4. Natural Conditions Clauses (only as they applies to human health) for waters in Indian lands
No material effect (see Section 1.2.1)
No material effect (see Section 1.2.1)
N/A
5. pH for fresh waters in Indian lands
Section 2.2.5
Section 3.1.4

No incremental costs (see Section 3.1.4)
6. Temperature criteria for tidal waters in Indian lands
Section 2.2.6
Section 3.1.5
No incremental costs (see Section 3.1.5)
7. Mixing zone policy for waters in Indian lands
Section 2.2.7
Section 3.1.6
Sections 4.4 and 6.1
8. Waiver or modification of protection and improvement laws for all state waters.
No material effect (see Section 1.2.1)
No material effect (see Section 1.2.1)
N/A
9. Numeric criteria for DO in Class A waters statewide.
Section 2.2.8
Section 3.2
No incremental costs (see Section 3.2)
10. Phenol criteria for protection of human health (water and organisms) to correct mathematical error, for state waters outside of Indian lands
Section 2.2.2
Section 3.3
No incremental costs (see Section 3.3)
1. Items in italics are expected to have no material effect on dischargers and are therefore not addressed in this economic analysis. 

Baseline for the Analysis
This section describes the applicable baseline for evaluating the incremental costs associated with the proposed WQS including potential sources of the pollutants of concern, current water quality impairments, disapproved water quality criteria and associated implementation procedures.
Sources of Pollutants to Surface Waters
Pollutants can be introduced to surface water through natural and human activities, including municipal and industrial effluents, stormwater discharges, septic systems, fish hatcheries, agricultural runoff, forestry, atmospheric deposition, and contaminated sediments. 
Municipal and Industrial Dischargers
EPA's Integrated Compliance Information System (ICIS) lists 69 major and 409 non-major MEPDES permitted dischargers in Maine. Exhibit 2-1 provides the number of facilities by type (non-major/major) and category (based on standard industrial classification (SIC) codes provided in ICIS). It also shows the number of facilities that discharge to waters in Indian lands or their tributaries. Pollutants depend on the type of facility, but may include metals and other toxics, bacteria, nutrients, biological oxygen demand and other organic compounds, and elevated temperature from non-contact cooling water.
Most major dischargers in Maine are POTWs (57 out of 69 major dischargers). The remaining 12 major dischargers are industrial facilities categorized as wood product, pulp or paper mills (9 facilities), electrical services (2 facilities), or industrial machinery and equipment manufacturers (1 facility).
Of the 33 facilities that discharge to waters in Indian lands or their tributaries, 15 are POTWs (6 of which are major dischargers). The remaining dischargers consist of two wood products, pulp, or paper mills (one of which is a major discharger), nine hydropower projects, two educational establishments (listed under "Not Categorized or Unknown" in Exhibit 2-1), one food manufacturing facility, two drinking water treatment plants, and two fish hatcheries. 
Exhibit 2-1. Number of Dischargers in Maine, by Category
Category (Based on SIC Code)
Non-Major
Major
All
Indian Lands or Tributaries
01-02: Crop and Animal Agriculture
                                      11
                                       0
                                      11
                                       
09: Aquaculture
                                      32
                                       0
                                      32
                                       2
16: Heavy Construction
                                       1
                                       0
                                       1
                                       
20: Food Manufacturing
                                      17
                                       0
                                      17
                                       1
22-23: Textile and Textile Products Manufacturing
                                       2
                                       0
                                       2
                                       
24-26: Wood Products, Pulp, and Paper
                                       5
                                       9
                                      14
                                       2
28: Chemicals and Chemical Preparations
                                       4
                                       0
                                       4
                                       
30-31: Plastics and Leather Products 
                                       2
                                       0
                                       2
                                       
35-36: Industrial Machinery and Equipment
                                       1
                                       1
                                       2
                                       
37: Transportation Equipment Manufacturing
                                      13
                                       0
                                      13
                                       
40: Rail Transportation
                                       1
                                       0
                                       1
                                       
49: Utilities
                                       
                                       
                                       
                                       
   4911: Electric Services
                                      37
                                       2
                                      39
                                       9
   4952: Sewerage Systems
                                      97
                                      57
                                      154
                                      15
   All Other Utilities
                                      24
                                       0
                                      24
                                       2
50-51: Durable and Nondurable Goods
                                      14
                                       0
                                      14
                                       
65-97: All Others (Including Not Categorized)
                                      35
                                       0
                                      35
                                       
91-97: Government
                                       3
                                       0
                                       3
                                       
Not Categorized or Unknown
                                      110
                                       0
                                      110
                                       2
Total
                                      409
                                      69
                                      478
                                      33
Source: Summary developed based on data from the EPA ICIS database, and supplementary data from facility fact sheets. Categorizations based on 4-digit SIC codes. Includes permits with expiration date between 2/28/2012 and 8/30/2020.
                                       
Urban Stormwater
Stormwater discharges are generated by precipitation and runoff from land, pavements, building rooftops, and other surfaces. Stormwater from municipal and industrial areas may contribute pollutants, including sediment, nutrient, and toxic pollutants (such as the pollutants addressed by the proposed HHC), to surface waters (for example, see MEDEP, 2014). Changes in the routing, magnitude, and timing of the stormwater also results in changes in the flow regime of rivers, including flash floods and associated bank erosion and habitat destruction. 
Maine has a population of 1.3 million people, concentrated mostly in the southern part of the state and the coastline. While only approximately 3 percent of Maine's landscape is developed lands and paved ways (MEDEP, 2014), stormwater runoff and other development-related impacts are significant causes of impairment or stressors for the state's waters (see Section 2.2). 
In particular, runoff from impervious cover is responsible for 54 miles of rivers and streams not meeting WQS for aquatic life use, while other stormwater-related sources are responsible for impairment of 92 miles of rivers and streams (MEDEP, 2012). Stormwater runoff is also a significant source of lake impairments. To address stormwater runoff as the source of impairment in 29 segments of rivers and streams across the state, MEDEP developed a statewide impervious cover TMDL. The TMDL sets targets for the percentage of total impervious cover (%IC) in watersheds and determines reductions in stormwater runoff volume and associated pollutants that may be needed to meet WQS. These reductions may be achieved by using best management practices (BMPs) and low impact development (LID) techniques, as described in a watershed management plan (WMP) specific to each location. The use of the %IC metric is based upon the observed relationship between the amount of human disturbance within a watershed and the decline in aquatic communities in streams and overall ecosystem health.
MEDEP regulates land use activities through five statutes: the Erosion and Sedimentation Control Law; the Site Location of Development Law; the Storm Water Management Law; the Mandatory Shoreland Zoning Act; and the Natural Resources Protection Act. These regulations control the type of development activities that may take place in various areas and BMPs that must be implemented to mitigate impact during and after construction. Other programs focus on reducing impacts from fertilizer application and road-salt management. 
MEDEP regulates stormwater discharges from small municipal separate storm sewer systems (MS4s) through a general permit (MEDEP, 2013). This permit covers 30 municipalities, eight state or federally owned facilities, and 2 transportation agencies (Maine Department of Transportation and Maine Turnpike Authority). This general permit requires the permittees to develop, implement, and enforce a stormwater management program (SWMP) including six minimum control measures: public education and outreach on stormwater impacts, public involvement and participation, illicit discharge detection and elimination, construction site stormwater runoff control, post-construction stormwater management in new development and redevelopment, and pollution prevention (P2)/good housekeeping for municipal operations.
Industrial dischargers, including those engaged in manufacturing, transportation, mining, and steam electric power industries, scrap yards, landfills, certain sewage treatment plants, and hazardous waste management facilities may have stormwater requirements in their individual MEPDES permits. Additionally, MEDEP issued a Multi-Sector Industrial Stormwater general permit (MEDEP, 2011), which covers stormwater discharges from industrial activities and requires facility owners to file a notice of intent (NOI) for coverage and develop a Stormwater Pollution Prevention Plan that includes BMPs to prevent, control, and treat stormwater pollution, a monitoring plan and discussion of the site controls that the discharger will implement to prevent stormwater pollution. The permit also includes additional requirements for 31 specific sectors.
Onsite Wastewater Disposal Systems 
According to the Maine Division of Environmental Health (MEDEH, 2015a), Maine households are predominantly rural, relying heavily on onsite wastewater disposal systems (OSDS), or septic systems. Data from the U.S. Census Bureau (1990) indicates that in 1990, over half of homes in Maine utilized these systems (301,373 compared with 266,344 on public sewerage systems and 19,328 using some other means). The number of households in Maine has increased since 1990 by about 24 percent (based on 727,632 households in 2014 U.S. Census Bureau, 2014). More recent data on the share of households using OSDS is not available; however, the MEDEH processes approximately 10,000 system permits annually (MEDEH, 2015b), suggesting that OSDS are still a predominant wastewater disposal method for Maine households. 
When properly installed, maintained, and operated, these systems can provide safe and effective sanitation in areas that lack centralized municipal wastewater collection. Malfunctioning disposal systems can cause bacterial contamination and deliver excess nutrients to surface waters. Maine's Department of Health and Human Services (DHHS) is responsible for rules addressing the disposal of wastewater, sets design and installation criteria, issues permits and installer certifications, conducts inspections, and provides grants to facilitate replacement of malfunctioning septic systems. 
Agriculture and Forestry
Forests account for over two thirds (69 percent) of Maine's landscape while land in agricultural production represents another 6 percent (MEDEP, 2014). Pesticides applied to agricultural or forestry lands can reach surface waters through irrigation return flow, stormwater runoff, and erosion of soils. Timber harvesting operations can also release sediment and nutrients. The Department of Agriculture, Conservation, and Forestry (DACF) and the Maine Forest Services, respectively, have primary responsibility to control runoff from agricultural and forestry lands. 
MEDEP has identified agriculture as a source of impaired water quality for 6 lakes (10,532 acres) and 358 miles of rivers and streams. Pollutants of concern in these waters include bacteria, soil, fertilizers, and pesticides (MEDEP, 2014). The DACF promotes the widespread use of agricultural BMPs through the Nutrient Management Act, which primarily aims to reduce nutrient runoff from livestock, and the Agricultural Compliance Program, which promotes, inspects, and assists with the implementation of agricultural BMPs. 
Maine has the highest percentage of forested land of any state, and approximately 450,000 acres are harvested annually (MEDEP, 2014). The Maine Forestry Service promotes the widespread use of forestry BMPs for all forestry operations. Pursuant to the Nonpoint Source (NPS) Management Program Statute (38 M.R.S. Article 1-F), it has developed BMP guidance and programs, and provides BMP assistance to landowners and wood harvesters.
Note that fish hatcheries are point sources covered by individual MEPDES permits in Maine and are therefore addressed in this analysis.
Atmospheric Deposition
Atmospheric deposition may be a potential nonpoint source to surface waters through either direct or indirect deposition. Direct deposition occurs when pollutants are deposited directly on surface waters from the atmosphere. Indirect deposition reflects the process by which metals and other pollutants such as pesticides deposited on the land surface are washed off during storm events and enter surface water through stormwater runoff. 
Maine has a statewide fish consumption advisory due to mercury levels. In 2007, an estimated 98 percent of the total load of mercury to Northeast freshwater bodies was due to atmospheric deposition (Connecticut DEP et al., 2007). Since then, EPA has promulgated regulations aimed at curbing emissions of mercury from coal-fired power plants and other sources. Atmospheric deposition is not directly addressed through any existing regulation, but may be indirectly addressed through TMDLs in estimating load allocations. Maine is covered by the Northeast Regional Mercury TMDL, which outlines strategies for reducing mercury concentrations in fish and achieving a target of 0.2 milligrams per kilogram (mg/kg) or parts per million (ppm) fish tissue residue of mercury in the edible portion of fish in Maine. These strategies include focusing on atmospheric deposition to achieve the bulk of loading reductions while ensuring that loadings from point sources remain small. 
Contaminated Sediments
When pollutants enter a waterbody through runoff, precipitation, or other means, they can accumulate in sediments and contribute to poor water quality for many years (U.S. EPA, 2012). Many waterbody sediments are contaminated by legacy pollutants including polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT) and other pesticides, which contribute to impairments of these waters even decades after discharges of these pollutants have ceased. Thus, several of Maine's major freshwater streams (e.g., Androscoggin River, Kennebec River, and Penobscot River) have fish consumption advisories based on elevated DDT, dioxin, and PCB levels. A state-wide advisory for dioxins and PCBs also applies to all coastal waters (U.S. EPA, 2015b). These advisories either provide recommended guidelines for the consumption of fish by certain subpopulation(s) or advise against consumption of fish from the affected waterbodies by the general population. In general, the state advises consumers to follow the most limiting guideline, based on mercury, DDT, dioxins, or PCBs.
Baseline Water Quality and Criteria 
Water Quality Impairments
According to Maine's 2012 Integrated Report, which identifies impaired waters and reports on the status of water quality statewide, 95 percent of assessed rivers and streams miles, 91 percent of assessed lake acres and 94 percent of assessed marine waters fully attained the State's WQS (MEDEP, 2012). For the remaining waters, MEDEP identified one or more sources of impairment because of exceedances of one or more applicable WQS. Exhibit 2-2 summarizes causes of impairments for rivers and streams, lakes, and marine waters. 
Exhibit 2-2. Cumulative Size of Impaired Waters by Listing Cause/Stressor Type
Cause of Impairment
River/stream (miles)
Lake
(acres)
Marine waters (square miles)
Pathogens / Bacteria
                                                                            175
                                                                               
                                                                            159
   Nonpoint sources and combined sewer overflows
                                                                       Variable
                                                                               
                                                                       Variable
Aquatic Life Criteria
                                                                               
                                                                               
                                                                               
   Integrated effects including biocriteria, habitat and
   nutrient biological indicators
                                                                            408
                                                                               
                                                                               
   Habitat assessment (lake)
                                                                               
                                                                         48,964
                                                                               
   Marine life
                                                                               
                                                                               
                                                                              1
Oxygen depletion
                                                                            475
                                                                            634
                                                                               
   Dissolved oxygen
                                                                            464
                                                                               
                                                                              6
   BOD
                                                                             21
                                                                               
                                                                               
   Sediment oxygen demand
                                                                               
                                                                               
                                                                          <1
Altered flow regime
                                                                             31
                                                                               
                                                                               
   Fish passage barrier
                                                                            4.5
                                                                               
                                                                               
Nutrients
                                                                            243
                                                                               
                                                                               
   Nutrient/eutrophication, biological indicators
                                                                            184
                                                                               
                                                                              2
   Phosphorus (total)
                                                                               
                                                                         36,234
                                                                               
Total inorganics
                                                                             26
                                                                               
                                                                               
   Methylmercury
                                                                               
                                                                        986,952
                                                                               
   Metals-copper
                                                                               
                                                                               
                                                                          <1
Total organics
                                                                            422
                                                                               
                                                                               
   Dioxins
                                                                            371
                                                                               
                                                                          2,846
   PCBs
                                                                            418
                                                                               
                                                                          2,846
   Pesticides
                                                                            217
                                                                               
                                                                               
   DDT
                                                                            214
                                                                               
                                                                               
pH, acidity, caustic conditions
                                                                              1
                                                                               
                                                                               
Sedimentation
                                                                             15
                                                                               
                                                                               
Harmful algae blooms
                                                                              8
                                                                               
                                                                               
Secchi Disk Transparency
                                                                               
                                                                         35,600
                                                                               
Turbidity
                                                                               
                                                                          7,865
                                                                               
Unknown
                                                                               
                                                                               
                                                                              2
Source: Based on 2012 Maine Integrated Water Quality Report; Tables 4-10 to 4-14).

The most recent assessment identified industrial and municipal (primarily POTW) point source discharges as the first and fifth most important sources of impairments, respectively, for rivers and streams in terms of impaired miles. These sources represent 452.5 miles of impaired rivers and 168 miles of impaired streams. Other impairment sources include unspecified non-point sources, agriculture, development-related sources (such as urban stormwater, impervious surfaces/parking lot runoff, and post-development erosion and sedimentation), dam or impoundment, and others.
Sources of impairments for lakes include atmospheric deposition of toxics (which represents the largest impact in terms of impaired lake area), followed by impacts from hydro-structures, flow regulation/modification, residential development, agriculture (e.g., crop production and livestock grazing or feeding operations), and others. 
Finally, MEDEP identified legacy pollutants as the most important contributor to impairments in marine waters, by impaired area, with CSOs being a variable contributor.
Since 1998, the state developed, and EPA approved, TMDLs for 23 lakes and 14 rivers/streams to address impairments previously identified by the state. 
Toxics
Exhibit 2-3 shows the Maine HHC (06-096 Chapter 584, Appendix A) that EPA disapproved and for which EPA proposes to promulgate HHC. These are the "baseline" criteria against which EPA's proposed criteria are compared for evaluating potential incremental cost impacts. The table also shows aquatic life criteria for freshwater and marine waters, where they exist for the pollutants for which there are HHC. 
Exhibit 2-3. Baseline Water Quality Criteria for Toxic Priority Pollutants in Maine[1]
Pollutant
Freshwater Aquatic Life (ug/L)
Marine Aquatic Life (ug/L)
Human Health (ug/L)

Acute
Chronic
Acute
Chronic
Water and Organisms
Organisms Only
1,1,2,2-Tetrachloroethane

0.16
2.2
1,1,2-Trichloroethane

0.58
8.42
1,1-Dichloroethylene

320
3900
1,2,4,5-Tetrachlorobenzene

0.55
0.58
1,2,4-Trichlorobenzene

25
38
1,2-Dichlorobenzene

330
700
1,2-Dichloropropane

0.50
7.9
1,2-Diphenylhydrazine

0.03
0.11
1,2-Trans-Dichloroethylene

140
5500
1,3-Dichlorobenzene

250
520
1,3-Dichloropropene

0.34
11.4
1,4-Dichlorobenzene

50
105
2,4,5-Trichlorophenol

1300
2000
2,4,6-Trichlorophenol

0.93
1.31
2,4-Dichlorophenol

63.3
160
2,4-Dimethylphenol

280
460
2,4-Dinitrophenol

68.4
2900
2,4-Dinitrotoluene

0.11
1.83
2-Chloronaphthalene

650
850
2-Chlorophenol

55.2
80.6
2-Methyl-4,6-Dinitrophenol

12.5
155
3,3'-Dichlorobenzidine

0.013
0.015
4,4'-DDD

0.00017
0.00017
4,4'-DDE

0.00012
0.00012
4,4'-DDT
1.1
0.001
0.13
0.001
0.00012
0.00012
Acenaphthene

430
540
Acrolein
3
3

3.9
5.0
Aldrin
3

1.3

2.7E-05
2.7E-05
alpha-BHC

0.0017
0.0026
alpha-Endosulfan
0.22
0.056
0.034
0.0087
39
48
Anthracene

7100
22000
Antimony

5.5
350
Benzene-Upper CSF

0.58
7.55
Benzo (a) Anthracene

0.003
0.01
Benzo (a) Pyrene

0.003
0.01
Benzo (b) Fluoranthene

0.003
0.01
Benzo (k) Fluoranthene

0.003
0.01
beta-BHC

0.006
0.009
beta-Endosulfan
0.22
0.056
0.034
0.0087
39
48
Bis(2-Chloro-1-Methylethyl) Ether

1350
35000
Bis(2-Chloroethyl) Ether

0.029
0.28
Bis(2-Ethylhexyl) Phthalate

0.8
1.19
Bromoform

4.2
73
Butylbenzyl Phthalate

900
1050
Carbon Tetrachloride

0.23
0.89
Chlordane
2.4
0.0043
0.09
0.004
0.00044
0.00044
Chlorobenzene

120
840
Chlorodibromomethane

0.40
6.94
Chrysene

0.003
0.01
Cyanide
22
5.2
1
1
140
140
Dibenzo (a,h) Anthracene

0.003
0.01
Dichlorobromomethane

0.53
9.3
Dieldrin
0.24
0.056 O
0.71
0.0019
2.9E-05
2.9
Diethyl Phthalate

13000
24000
Dimethyl Phthalate

221000
600000
Di-n-Butyl Phthalate

1400
2400
Dinitrophenols

68
2860
Endosulfan Sulfate

39
48
Endrin
0.086
0.036
0.037
0.0023
0.032
0.032
Endrin Aldehyde

0.16
0.16
Ethylbenzene

435
1150
Fluoranthene

71
75
Fluorene

950
2100
gamma-BHC (Lindane)
0.95

0.16

0.68
0.1
Heptachlor
0.52
0.0038
0.053
0.0036
4.3E-05
4.3E-05
Heptachlor Epoxide
0.52
0.0038
0.053
0.0036
2.1E-05
2.1E-05
Hexachlorobenzene

0.0002
0.0002
Hexachlorobutadiene

0.43
9.96
Hexachlorocyclohexane-Technical

0.0123
0.0414
Hexachlorocyclopentadiene

39
600
Hexachloroethane

1.04
1.78
Indeno (1,2,3-cd) Pyrene

0.003
0.01
Isophorone

35
520
Methoxychlor

0.03

0.03
100

Methylene Chloride

4.6
320
Methylmercury

0.2 mg/Kg
Nickel
120.2
13.4
75
8.28
400
1000
Nitrobenzene

16.7
370
Nitrosamines

0.0008
1.24
N-Nitrosodibutylamine

0.0061
0.118
N-Nitrosodiethylamine

0.0008
1.24
N-Nitrosodimethylamine

0.00069
1.63
N-Nitrosodi-n-propylamine

0.005
0.27
N-Nitrosodiphenylamine

2.23
3.24
N-Nitrosopyrrolidine

0.016
18.4
Pentachlorobenzene

0.79
0.81
Pentachlorophenol
8.72
6.69
13
7.9
0.25
1.64
Phenol

10514
462963
Polychlorinated Biphenyls (PCBs)

0.014

0.03
3.5E-05
3.5E-05
Pyrene

710
2160
Selenium

5
291
71
162
2250
Toluene

1200
8100
Toxaphene
0.73
0.0002
0.21
0.0002
0.00015
0.000155
Trichloroethylene

2.37
16.2
Vinyl Chloride

0.025
1.32
Zinc
30.6
30.6
95
86
6000
14000
Source: MEDEP Regulation 06-096 CMR 584, Appendix A,and 38 MRS § 420(1-B). See original source for additional notes on criteria applicability or basis.
[1] The table does not include additional priority pollutants for which the State of Maine established aquatic life criteria only (e.g., Cadmium, Chromium III and Chromium VI).

As discussed in Section 2.1.5, a large fraction of state waters are impaired for mercury from atmospheric deposition from sources outside the region. State law prohibits the discharge of mercury and directs facilities to develop and implement P2 practices to reduce and remove mercury discharges over time (38 MRS § 420), and authorizes MEDEP to establish interim discharge limits to reduce the discharge of mercury and achieve ambient water quality criteria for mercury (38 MRS § 413(11)). MEDEP Rule, in turn (06-096 Chapter 519) specifies that such interim mercury limits must be based upon  -  and no less stringent statistically  -  than past discharge levels, and that such interim limits shall not authorize any discharge of mercury that would cause or contribute to receiving water concentrations of mercury that exceed any water quality criteria published by EPA. Under Chapter 519, MEDEP controls mercury discharges from point source dischargers to surface waters through effluent limitations, monitoring requirements, and P2 plan requirements. These limitations and requirements apply to all permittees that have the potential to discharge wastewaters that may contain or come into contact with mercury. Each facility is required to develop and implement a P2 plan (based on model plans developed by MEDEP), and conduct effluent monitoring for mercury at least 3 times a year. Additionally, MEDEP establishes interim mercury effluent limits for each permittee based on the facility's mean mercury effluent concentration adjusted to account for the standard error and confidence level. Further, in accordance with Chapter 519, the facility does not violate the ambient criteria for mercury if the facility is in compliance with its interim discharge limit or with a remediation or corrective action plan, license or order approved either by MEDEP or the U.S. EPA.
As discussed later in Section 3, EPA is proposing HHC (based on the consumption of water and organisms and for consumption of organisms only) for waters in Indian lands to address the disapproved criteria presented in Exhibit 2-3. 
There are little available data on ambient levels of these pollutants in waters in Indian lands. EPA reviewed the available monitoring data to characterize the quality of surface waters in Indian lands. EPA identified 66 monitoring locations that were sampled during the period of 2000 through 2015 within Indian lands, with very little monitoring data for the set of toxic pollutants for which EPA is proposing HHC. 
As discussed in Section 1.2.2, EPA is proposing two phenol criteria for water plus organisms  --  one for waters in Indian Lands and one for all other state waters. EPA found no data to characterize baseline phenol levels in either waters in Indian lands or other state waters; available water quality monitoring data provide no water column results for phenol and the integrated assessment report makes no mention of phenol as a concern.
Bacteria
As summarized in Exhibit 2-2, as of the 2012 integrated water quality assessment, approximately 175 miles of rivers and streams and 159 square miles of estuarine and marine waters (excluding waters listed based on Combined Sewer Overflows) were identified as impaired due to elevated bacterial counts. Bacteria levels are monitored by MEDEP in selected urban streams, by the Maine Healthy Beaches program in swimming beaches and in tidal waters that influence bacterial loads to recreational areas, and by the Department of Marine Resources (DMR) to determine shellfish harvest closures (MEDEP, 2012). 
In 2009, the State completed the development of a statewide bacteria TMDL to address sources of bacteria in both freshwaters and marine waters associated with impairments of certain river and stream segments and estuarine and marine segments in several major basins. The TMDL aims to meet the bacterial WQS for recreation and shellfish consumption at the point of discharge for all sources and to implement BMPs to reduce bacteria loadings from non-point sources (ENSR, 2009). 
Through this action, EPA is proposing recreational bacteria criteria for waters in Indian lands. Accordingly, EPA reviewed water quality reported for these waters more specifically to assess baseline conditions. Based on information provided on the Maine Healthy Beaches program website, none of the coastal beaches monitored by that program are located in or near Indian lands. Monitoring data submitted to the EPA's Water Quality Portal from other programs for these waters is limited to 62 observations from 20 locations sampled in 2005, 2008 or 2011. The data show maximum reported E. coli levels of 64 cfu/100 ml (60 samples) and maximum enterococci levels of 71 cfu/100 ml (2 samples). EPA notes that three plants discharge to waters in Indian lands or their tributaries (St. Croix River and Piscataquis River) that MEDEP previously listed as impaired due to elevated bacterial levels, as detailed in the statewide bacteria TMDL. 
EPA is also proposing total coliform bacteria criteria for shellfishing in Class SA waters in Indian lands. At present it appears that there are no Class SA waters in Indian lands.
Ammonia
Maine's ammonia criteria for freshwater depend on pH and temperature (T). Chapter 584 specifies that the one-hour average concentration of total ammonia nitrogen (in mg N/L) shall not exceed, more than once every three years on the average, the CMC (criterion maximum concentration, or acute criterion) calculated using the following equations: 
CMC=0.2751+107.204-pH+39.01+10pH-7.204
Whereas the thirty-day average concentration of total ammonia nitrogen (in mg N/L) shall not exceed, more than once every three years on the average, the CCC (criterion continuous concentration, or chronic criterion) calculated using the following equation: 
  CCC=0.05771+107.688-pH+2.4871+10pH-7.688xmin⁡(2.85,1.45x100.028(25-T))
In addition, the highest four-day average within the 30-day period shall not exceed 2.5 times the CCC.
At a temperature of 25ºC and pH of 7.0, the acute criterion is 24.1 mg/L whereas the chronic criterion is 3 mg/L. Through this action, EPA is proposing ammonia criteria for waters in Indian lands. Accordingly, EPA reviewed ammonia concentrations for these waters to assess baseline conditions. None of the waters are listed as impaired due to ammonia levels. Available water quality monitoring data shows only six water samples collected from waters in Indian lands were analyzed for ammonia levels. These samples were all collected by the USGS in 2008 or 2009 and show levels that range between 0.01 mg/L and 0.036 mg/L as N.
pH
Maine law, at 38 M.R.S §464(4.A(5)), prohibits effluent discharges that cause the pH of fresh waters to fall outside of the 6.0 to 8.5 range. A review of existing permits for facilities that discharge to waters in Indian lands also show additional provisions allowing discharges outside the specified pH range for effluent if the discharge is within 0.5 standard units (SU) of the pH of the ambient receiving water pH (e.g., Woodland Pulp permit).
In addition to industrial point source discharges, pH levels may be affected by atmospheric deposition and impacts from legacy pollution. There are no rivers or streams in Indian lands that are listed as impaired for pH. 
EPA reviewed available water quality monitoring data collected from waters in Indian lands. The data show pH values ranging from 3.6 to 9.1. 
Tidal Temperature
MEDEP Chapter 582 establishes a not-to-exceed criterion of 85ºF outside of the discharge mixing zone in marine waters. Maine also limits discharges from causing the monthly mean of the daily maximum ambient temperatures in any tidal waterbody to be raised more than 4ºF at any time, or more than 1.5ºF from June 1 to September 1 (summer months). Through this action, EPA is proposing tidal temperature criteria for tidal waters in Indian lands, which consist of the waters within the intertidal zone at the Passamaquoddy Pleasant Point reservation. Currently there are no permittees that discharge heat to tidal waters in Indian lands.
Mixing Zone
The mixing zone policy for Maine is contained in 38 MRS Section 451 "Enforcement Generally" which states:
The purpose of a mixing zone is to allow a reasonable opportunity for dilution, diffusion or mixture of pollutants with the receiving waters before the receiving waters below or surrounding a discharge will be tested for classification violations. In determining the extent of any mixing zone to be established under this section, the department may require from the applicant testimony concerning the nature and rate of the discharge; the nature and rate of existing discharges to the waterway; the size of the waterway and the rate of flow therein; any relevant seasonal, climatic, tidal and natural variations in such size, flow, nature and rate; the uses of the waterways in the vicinity of the discharge, and such other and further evidence as in the department's judgment will enable it to establish a reasonable mixing zone for such discharge. An order establishing a mixing zone may provide that the extent thereof varies in order to take into account seasonal, climatic, tidal and natural variations in the size and flow of, and the nature and rate of, discharges to the waterway. 
Maine's mixing zone policy does not specify how such zones are to be established (other than through the application of best professional judgment).
Within the set of 33 facilities that discharge to waters in Indian lands or their tributaries, EPA identified Woodland Pulp LLC as the only facility for which the permit establishes a mixing zone that may extend to waters in Indian lands. 
Woodland Pulp LLC is currently permitted to contribute large thermal loadings to the St. Croix River and has an extensive thermal mixing zone (9.3 miles long). MEDEP established the limits of this mixing zone many years (and permit cycles) ago and information on site-specific studies or models used to establish compliance is limited or not readily available for review. The current permit employs a variation of a mass balance using effluent temperature and river flow to calculate predicted river temperature increase at the edge of the mixing zone and compare this temperature to applicable criteria. There are currently no in-stream monitoring requirements in the permit, although it does require the permittee to investigate technological alternatives to reduce cumulative thermal loading from the facility and report on projects and estimate reduced heat load as part of the next permit application. 
Dissolved Oxygen
Maine's standards for Class A waters set minimum DO concentrations at 7 ppm and minimum DO saturation at 75 percent. EPA reviewed water quality monitoring data for sampling locations on Class A waters. Of 193 samples collected by MEDEP over the last five years, eight showed DO levels that were less than MEDEP's criteria of 7 ppm or 75 percent saturation. 
As of its 2012 Integrated Report, MEDEP added one Class A stream in the list of rivers and streams impaired due to DO levels: a 15.78 miles segment of Prestile Stream above a dam in Mars Hill. A TMDL has been approved for this waterbody to address water quality stressors associated with nonpoint source runoff. 
Impact from nonpoint sources is an important factor in river and stream DO impairments more generally. Thus, according to MEDEP's water quality assessment for 2012, two thirds of the 42 waters listed as impaired due to oxygen depletion (across water quality classes) had agriculture or other nonpoint sources as a probable source for the impairment.

Proposed Criteria
This section describes the criteria EPA is proposing for waters in Indian lands (Section 3.1) and for other state waters (Section 3.2). The discussion highlights those proposed criteria that may have cost implications, as further analyzed in Sections 4 and 5.
Proposed Criteria for Waters in Indian Lands 
Human Health Criteria
Exhibit 3-1 summarizes the proposed HHC for waters in Indian lands derived using the fish consumption rate of 286 g/day and EPA's most recent recommendations for other criteria inputs. For comparison, the table also provides MEDEP's baseline criteria, which were derived using a FCR of 32.4 g/day. Finally, Exhibit 3-1 provides MEDEP's specified reporting limits (RLs), which represent the minimum level to which dischargers need to measure each pollutant according to the existing permit conditions. 
Of particular relevance for this analysis are proposed criteria that result in more stringent criteria than exist in the baseline. EPA did not consider further those pollutants for which the proposed HHC are higher than existing aquatic life criteria because the aquatic life criteria would be the determining factor in setting effluent limitations. The proposed HHC for alpha-endosulfan, beta-endosulfan, nickel, selenium, and zinc (2 ug/L, 3 ug/L, 20 ug/L, 21 ug/L, and 300 ug/L, respectively) are less stringent than the state's existing freshwater aquatic life criteria, which EPA has approved for waters in Indian lands (0.056 ug/L, 0.056 ug/L, 13.4 ug/L, 5.0 ug/L, and 30.6 ug/L, respectively; see Exhibit 2-3). Therefore EPA assumed that the proposed rule would not lead to additional compliance costs for these pollutants, and EPA did not evaluate them further.
Exhibit 3-1. Proposed Human Health Criteria for the Consumption of Water and Organisms and Organisms Only (ug/L)
Pollutant[1]
Proposed Human Health Criterion
Maine DEP Reg. 584 Appendix A Table 1
Maine DEP Reporting Limit

Water and Organisms[2]
Organisms Only[3]
Water and Organisms
Organisms Only

1,1,2,2-Tetrachloroethane
0.09
0.2
0.16
2.2
7
1,1,2-Trichloroethane
0.31
0.66
0.58
8.42
5
1,1-Dichloroethylene
300
1000
320
3900
3
1,2,4,5-Tetrachlorobenzene
0.002
0.002
0.55
0.58
not found
1,2,4-Trichlorobenzene
0.0056
0.0056
25
38
5
1,2-Dichlorobenzene
200
300
330
700
5
1,2-Dichloropropane
-
2.3
0.50
7.9
6
1,2-Diphenylhydrazine
0.01
0.02
0.03
0.11
20
1,3-Dichlorobenzene
1
1
250
520
5
1,3-Dichloropropene
0.21
0.87
0.34
11.4
5
1,4-Dichlorobenzene
-
70
50
105
5
2,4,5-Trichlorophenol
40
40
1300
2000
2.5
2,4,6-Trichlorophenol
 0.20
0.21
0.93
1.31
5
2,4-Dichlorophenol
4
4
63.3
160
5
2,4-Dimethylphenol
80
200
280
460
5
2,4-Dinitrophenol
9
30
68.4
2900
45
2,4-Dinitrotoluene
0.036
0.13
0.11
1.83
6
2-Chloronaphthalene
90
90
650
850
5
2-Chlorophenol
20
60
55.2
80.6
5
2-Methyl-4,6-Dinitrophenol
1
2
12.5
155
not found
3,3'-Dichlorobenzidine
0.0096
0.011
0.013
0.015
16.5
4,4'-DDD
9.3E-06
9.3E-06
0.00017
0.00017
0.05
4,4'-DDE
1.3E-06
1.3E-06
0.00012
0.00012
0.05
4,4'-DDT
2.2E-6
2.2E-06
0.00012
0.00012
0.05
Acenaphthene
6
7
430
540
5
Acrolein
3
-
3.9
5.0
NA
Aldrin
5.8E-08
5.8E-08
2.7E-05
2.7E-05
0.15
alpha-BHC
2.9E-05
2.9E-05
0.0017
0.0026
0.2
alpha-Endosulfan
2
2
39
48
0.05
Anthracene
30
30
7100
22000
5
Antimony
 4.8
 45
5.5
350
5
Benzene
0.40
1.2
0.58
7.55
5
Benzo (a) Anthracene
9.8E-05
9.8E-05
0.003
0.01
8
Benzo (a) Pyrene
9.8E-06
9.8E-06
0.003
0.01
5
Benzo (b) Fluoranthene
9.8E-05
9.8E-05
0.003
0.01
5
Benzo (k) Fluoranthene
0.00098
0.00098
0.003
0.01
5
beta-BHC
0.0010
0.0011
0.006
0.009
0.05
beta-Endosulfan
3
3
39
48
0.05
Bis(2-Chloro-1-Methylethyl) Ether
100
300
1350
35000
6
Bis(2-Chloroethyl) Ether
0.026
0.16
0.029
0.28
6
Bis(2-Ethylhexyl) Phthalate
0.028
0.028
0.8
1.19
10
Bromoform
4.0
8.7
4.2
73
5
Butylbenzyl Phthalate
0.0077
0.0077
900
1050
5
Carbon Tetrachloride
0.2
0.3
0.23
0.89
5
Chlordane
2.4E-05
2.4E-05
0.00044
0.00044
0.1
Chlorobenzene
40
60
120
840
6
Chlorodibromomethane
-
1.5
0.40
6.94
3
Chrysene
-
0.0098
0.003
0.01
5
Cyanide
4
30
140
140
5
Dibenzo (a,h) Anthracene
9.8E-06
9.8E-06
0.003
0.01
5
Dichlorobromomethane
-
2
0.53
9.3
3
Dieldrin
9.3E-08
9.3E-08
2.9E-05
2.9E-05
0.05
Diethyl Phthalate
50
50
13000
24000
5
Dimethyl Phthalate
100
100
221000
600000
5
Di-n-Butyl Phthalate
2
2
1400
2400
5
Dinitrophenols
10
70
68
2860
not found
Endosulfan Sulfate
3
3
39
48
0.1
Endrin
0.002
0.002
0.032
0.032
0.05
Endrin Aldehyde
0.09
0.09
0.16
0.16
0.05
Ethylbenzene
8.9
 9.5
435
1150
10
Fluoranthene
1
1
71
75
5
Fluorene
5
5
950
2100
5
gamma-BHC (Lindane)
0.33
-
0.68
0.1
0.15
Heptachlor
4.4E-07
4.4E-07
4.3E-05
4.3E-05
0.15
Heptachlor Epoxide
2.4E-06
2.4E-06
2.1E-05
2.1E-05
0.1
Hexachlorobenzene
5.9E-06
5.9E-06
0.0002
0.0002
5
Hexachlorobutadiene
0.0007
0.0007
0.43
9.96
5
Hexachlorocyclohexane-Technical
0.00073
0.00076
0.0123
0.0414
not found
Hexachlorocyclopentadiene
0.3
0.3
39
600
10
Hexachloroethane
0.01
0.01
1.04
1.78
5
Indeno (1,2,3-cd) Pyrene
9.8E-05
9.8E-05
0.003
0.01
5
Isophorone
28
140
35
520
5
Methoxychlor
0.001
-
100
-
not found
Methylene Chloride
-
90
4.6
320
5
Methylmercury[4]

0.02 mg/kg in fish tissue

0.2 mg/kg mercury in fish tissue

Nickel
20
24
400
1000
5
Nitrobenzene
10
40
16.7
370
5
Nitrosamines
 0.0007
 0.0322
0.0008
1.24
not found
N-Nitrosodibutylamine
 0.0044
 0.015
0.0061
0.118
not found
N-Nitrosodiethylamine
 0.0007
 0.0322
0.0008
1.24
not found
N-Nitrosodimethylamine
0.00065
0.21
0.00069
1.63
5
N-Nitrosodi-n-propylamine
 0.0042
 0.035
0.005
0.27
10
N-Nitrosodiphenylamine

 0.40
0.42
2.23
3.24
5
N-Nitrosopyrrolidine
-
2.4
0.016
18.4

Pentachlorobenzene
0.008
0.008
0.79
0.81
not found
Pentachlorophenol
0.003
0.003
0.25
1.64
20
Phenol
3000
20000
10514
462963
5
Polychlorinated Biphenyls (PCBs)
4.5E-06

4.5E-06
3.5E-05
3.5E-05
0.3
Pyrene
2
2
710
2160
5
Selenium
21
58
162
2250
5
Toluene
24
39
1200
8100
5
Toxaphene
5.3E-05
5.3E-05
0.00015
0.000155
1
Trans-1,2-Dichloroethylene
90
300
140
5500
5
Trichloroethylene
0.3
0.5
2.37
16.2
3
Vinyl Chloride
0.019
0.12
0.025
1.32
5
Zinc
300
360
6000
14000
5
FCR = fish consumption rate
1. EPA disapproved HHCs for arsenic, thallium and 2,3,7,8-TCDD (Dioxin) but is not proposing criteria for these pollutants at this time.
2. Based on a total FCR of 286 g/day where the consumption rate ascribed to each trophic level was based on the same relative percent and trophic specific bioaccumulation factors adopted by EPA (2015a) when available and including a body weight of 80 kg and drinking water intake of 2.4 L/day and other 2015 updated parameters as available; For compounds not updated in 2015, proposed criteria are based on a FCR of 286 g/day and a relative source contribution of 0.2 save for antimony (RSC of 0.4), body weight of 80 kg, drinking water intake rate of 2.4 L/day, and bioconcentration factors and toxicity values from U.S. EPA (2002).
3. Based on total FCR of 286 g/day where the consumption rate ascribed to each trophic level was based on the same relative percent and trophic specific bioaccumulation factors adopted by EPA (2015a) when available including a body weight of 80 kg and other 2015 updated parameters as available; For compounds not updated in 2015, proposed criteria are based on a FCR of 286 g/day and a relative source contribution of 0.2 save for antimony (RSC of 0.4), body weight of 80 kg, and bioconcentration factors and toxicity values from U.S. EPA (2002).
4. This is a fish tissue based criterion that applies equally in fresh and marine waters. EPA has explained in the preamble to the proposed rule why it is proposing to promulgate a criterion for methylmercury rather than mercury. See Appendix B for derivation of total mercury water column concentration equivalent to the methylmercury fish tissue concentration criteria values for use in evaluating reasonable potential. EPA recognizes that Maine has established interim mercury limits for permittees based on 38 MRS § 420, which prohibits the discharge of mercury and directs facilities to develop and implement pollution prevention practices to reduce and remove mercury discharges over time; 38 MRS § 413(11), which authorizes DEP to establish interim discharge limits to reduce the discharge of mercury and achieve ambient water quality criteria for mercury; and DEP Rule Chapter 519, which specifies that such interim mercury limits must be based upon and no less stringent statistically than past discharge levels, and that such interim limits shall not authorize any discharge of mercury that would cause or contribute to receiving water concentrations of mercury that exceed any water quality criteria published by EPA. As discussed further in Section 4.1.2, EPA has concluded that none of the permittees that discharge to waters in Indian lands or their tributaries discharges mercury at a level that would have a reasonable potential to cause or contribute to an exceedance of EPA's proposed methyl mercury criterion.

Section 4.1 details EPA's analysis of the cost impacts of the proposed HHC for consumption of water and organisms and of organisms only for waters in Indian lands.
Bacteria
EPA is proposing recreational criteria for waters in Indian lands that follow the recommended criteria EPA finalized in 2012 to protect the public from exposure to harmful levels of pathogens while participating in primary contact recreational activities. The proposed criteria incorporate three components: magnitude, duration, and frequency as follows: 
In Class AA, Class A, Class B, Class C and Class GPA waters (i.e., freshwaters), Escherichia coli (E. coli) bacteria shall not exceed a geometric mean of 100 organisms per 100 ml obtained over a representative period of 30 days, nor shall a statistical threshold value of 320 organisms per 100 ml be exceeded by more than 10 percent of the time, in any 30-day interval. 
In Class SA, Class SB, and Class SC waters (i.e., estuarine and marine waters), enterococcus bacteria shall not exceed a geometric mean of 30 organisms per 100 ml obtained over a representative period of 30 days, nor shall a statistical threshold value of 110 organisms per 100 ml be exceeded by more than 10 percent of the time, in any 30-day interval.
In addition, for Class AA, A and SA waters, EPA is proposing to include Maine's narrative criteria expression that bacteria content of these waters be as "naturally occurs." This supports Maine's intention that the waters be free of human caused pathogens, while the specific numeric criteria EPA proposes also provide protection for designated recreational uses in the event there are wild animal sources.
EPA is proposing that the bacteria criteria apply year round in waters in Indian lands. This differs from Maine's disapproved criteria, which do not apply from October 1 through May 14 in Class B, C, GPA, SB, and SC waters. 
In Class SA shellfish harvesting areas, EPA is proposing that the number of total coliform bacteria in samples representative of the waters in shellfish harvesting areas shall not exceed a geometric mean for each sampling station of 70 MPN per 100 ml, with not more than ten percent of samples exceeding 230 MPN per 100 ml for the taking of shellfish. At present it appears that there are no Class SA waters in Indian lands, and therefore the proposed rule is not expected to result in incremental costs to permitted dischargers. 
Of the 33 facilities that discharge to waters in Indian lands or their tributaries, 12 facilities discharge to Class B or C waters and have existing limits for E. coli bacteria, and 3 facilities discharge to Class SB or SC waters and have existing limits for fecal coliform bacteria to protect shellfishing. All of the permits apply the bacteria limits only between May 15 and September 30.
As summarized in Exhibit 3-2, which compares the baseline and proposed criteria, permit limits for dischargers to Class B waters are based on not exceeding criteria of an instantaneous level of 236 E. coli colonies/100 ml and geometric mean of 64 colonies/100 ml; and permit limits for dischargers to Class C waters are based on not exceeding criteria of an instantaneous level of 236 E. coli colonies/100 ml and geometric mean of 126 colonies/100 ml. Further, MEDEP considers dilution in setting instantaneous effluent limits, resulting in end-of-pipe permit limits that may be significantly greater than the 236 E. coli colonies/100 ml criterion (e.g., the permit for Millinocket, which discharges to Class C waters, sets limits of 126 colonies/100 ml (monthly) and 949 colonies/100 ml (daily maximum)). 
The permits for discharges to Class SB and SC waters do not refer to Maine's enterococci criteria but rather set fecal coliform bacteria limits of a daily maximum of 50 colonies/100 mL and a monthly average limit of 15 colonies/100 mL (geometric mean) to meet shellfishing bacteria criteria. EPA does not endorse the absence of enterococci limits. However, for the purpose of this report, EPA believes it is reasonable to assume that the level of disinfection needed to meet the current fecal coliform bacteria limits will be adequate to meet EPA's proposed enterococci criteria.
Exhibit 3-2. Baseline and Proposed Bacteria Criteria 
Waters
Baseline
Proposed
Class AA, A
Bacteria content as "naturally occurs."
Bacteria content as "naturally occurs."
E.coli 30-day geometric mean no more than 100/100 ml nor shall 320/100 ml be exceeded more than 10 percent of the time in any 30-day interval 
Class B 
From May 15-Sept 30, E. coli of human and domestic origin geometric mean no more than 64/100 ml and instantaneous level no more than 236/100 ml. 
E.coli 30-day geometric mean no more than 100/100 ml nor shall 320/100 ml be exceeded more than 10 percent of the time in any 30-day interval
Class C
From May 15-Sept 30, E. coli of human and domestic origin geometric mean no more than 126 E.coli/100 ml and instantaneous level no more than 236/100 ml. 
1.  
SA
Bacteria content as "naturally occurs"
Bacteria content as "naturally occurs"
Enterococcus 30-day geometric mean no more than 30/100 ml nor shall 110/100 ml be exceeded more than 10 percent of the time in any 30-day interval 
Total coliform geometric mean no more than 70 MPN/100 ml and no more than 10 percent of samples above 230 total coliform MPN/100 ml.
Class SB
From May 15-Sept 30, enterococcus of human and domestic animal origin geometric mean no more than 8/100 ml and instantaneous level no more than 54/100 ml
Total coliform or other specified indicator organism may not exceed criteria recommended under the National Shellfish Sanitation Program.
Enterococcus 30-day geometric mean no more than 30/100 ml nor shall 110/100 ml be exceeded more than 10 percent of the time in any 30-day interval.

Class SC
From May 15-Sept 30, enterococcus of human and domestic animal origin geometric mean no more than 14/100 ml and instantaneous level no more than 94/100 ml.
Total coliform or other specified indicator organism may not exceed criteria recommended under the National Shellfish Sanitation Program
      

EPA's review of discharge monitoring reports (DMRs) from 13 of the 15 facilities with existing bacteria limits shows that the facilities are generally able to achieve levels below the proposed criteria at the point of discharge, before accounting for any dilution. Daily maximum values rarely exceed the proposed statistical threshold value of 320 E. coli colonies/100 mL for discharges to Class B and C waters, and total fecal coliform values for dischargers to Class SB and SC waters exceeded the specified monthly limit at only one facility once out of 18 monitoring periods between 2011 and 2015. Accordingly, EPA does not expect that the proposed bacteria criteria for waters in Indian lands will result in incremental costs to permitted dischargers for the period of May 15  -  September 30. However, EPA proposes that the recreational criteria will apply year round. Therefore EPA expects that there could be incremental costs associated with additional disinfection occurring during the period of October 1  -  May 14. EPA estimated additional costs for chlorination, dechlorination and monitoring for the entire period of October 1 through May 14 at each plant that currently disinfects its effluent between May 15 and September 30. Section 4.2 describes this analysis.
Impacts of the proposed criteria on nonpoint sources depend on current levels of bacteria in waters in Indian lands that may be used for primary contact recreation. As discussed in Section 2.2.3, the very limited water quality monitoring data EPA found for waters in Indian lands show no measurements that would exceed the statistical threshold values for E. coli, irrespective of any duration or frequency considerations (maximum measurement was 64 colonies/100 ml; data are not sufficient to calculate statistical distribution). Only two samples were analyzed for enterococci levels, with a maximum of 71 colonies per 100 ml (data are not sufficient to calculate statistical distribution). 
Ammonia
EPA is proposing to promulgate ammonia aquatic life ambient water quality criteria for waters in Indian lands. The national recommended criteria depend on both pH and temperature and, in the case of the acute criterion, on whether species of the Genus Oncorhynchus are present. For a pH of 7 and water temperature of 20 degrees Celsius, the acute criterion is 17 mg Total Ammonia Nitrogen (TAN) per liter (mg TAN/L) and the chronic criterion is 1.9 mg TAN/L (not to exceed 4.8 mg TAN/L as a 4-day average). 
Similar to Maine's baseline acute criterion for ammonia, the proposed acute criterion depends on both pH and temperature. For a given pH, the proposed acute criterion is generally less stringent or equal to the baseline acute criterion for water temperatures less than approximately 15 degrees Celsius. The proposed acute criterion becomes more stringent (i.e., lower ammonia concentrations) than the baseline criterion as water temperatures increase. Exhibit 3-3 compares the baseline and proposed acute criteria for ammonia for different pH values and temperatures. Similar to Maine's baseline chronic criterion for ammonia, the proposed chronic criterion depends on both pH and temperature; however, the proposed chronic criterion is consistently lower (i.e., more stringent) than the baseline criterion (see Exhibit 3-4) across the range of pH and temperatures. For example, the proposed criterion for a temperature of 25ºC and pH of 7 is 1.4 mg/L as compared to 3 mg/L for the baseline criterion.
Exhibit 3-3. Comparison of Maine's baseline (solid line) and EPA's proposed (dashed lines) ammonia acute criteria for different temperatures[1]

1. Note that the criteria are very similar for the existing CMC as well as the proposed  CMC at 0-14 deg C and at 15 deg C (Oncorhynchus spp. Present), and as such, the lines may not appear distinct from one another.

Exhibit 3-4. Comparison of Maine's baseline (solid lines) and EPA's proposed (dashed lines) ammonia chronic criteria for different water temperatures.

Of the 33 facilities with permits to discharge to waters in Indian lands or their tributaries, two currently have effluent limits for ammonia. Another seven facilities are required to monitor for ammonia as part of a broader analytical chemistry monitoring requirement. The remaining 24 facilities, including several POTWs, have neither effluent limits nor monitoring requirements for ammonia, although some may be expected to have small amounts of ammonia in their effluent. For the purpose of this analysis, EPA assumed that effluents from these facilities do not have reasonable potential to exceed the proposed ammonia criteria in waters in Indian lands.
Both facilities with ammonia limits discharge to the Piscataquis River:
Dover-Foxcroft WWTP (ME0100501): The permit sets a limit of 279 lbs/day (monthly average) based on monitoring data, which showed a reasonable potential to exceed the chronic ambient water quality criteria (AWQC; 3.0 mg/L at temperature of 25ºC and pH 7.0) downstream from the plant. The limit applies during June 1-September 30. The limit reflects load allocation on the Piscataquis River at Milo among three dischargers. 
Guilford-Sangerville (ME0102032): The permit sets a limit of 13 lbs/day (monthly average) based on the load allocation for the Piscataquis River at Milo.
A third facility discharging to the Piscataquis River (Milo, ME0100439) had its ammonia limit removed from the most recent permit following MEDEP's determination that the facility no longer had the potential to result in exceedances of the chronic AWQC for ammonia (3.0 mg/L at temperature of 25ºC and pH 7.0). 
Review of analytical chemistry and priority pollutant scan data showed several other facilities with detected ammonia concentrations.
Section 4.1 details EPA's analysis of the cost impacts of the proposed ammonia criteria for fresh waters in Indian lands.
pH 
Natural waters in Maine, as elsewhere in New England, could easily vary between 5.0-8.0 SU of pH for a variety of reasons (e.g., basin geology, buffering capacity, precipitation, and photosynthetic activity). MEPDES permits typically allow a wide range of pH levels for discharges, allowing them to accommodate discharges from plant operations or treatment units that might vary significantly in pH. Treatment of effluent to reduce metals can result in altered pH levels in the discharge. EPA's proposal to raise the lower value of the pH range from 6.0 to 6.5 SU could result in needed changes to facility operations in cases where existing treatment affects pH levels.
EPA reviewed data for six facilities that have permit limitations and detected effluent records for heavy metals (out of the total of 33 facilities discharging to waters in Indian lands or their tributaries). Five of these facilities can be expected to have little potential for costs based on their low flow, wastewater sources, and/or existing monitoring data. The remaining facility (Woodland Pulp) has a permit that allows for discharges of effluent within a wider pH range (5.0 to 9.0 SU) based on technology-based limits in Effluent Guidelines and Standards (ELGs) for the Pulp, Paper, and Paperboard Point Source Category (40 CFR 430). The facility adjusts the pH of its effluent before discharge and historical DMR data demonstrate that the facility has been able in the past to meet the proposed criterion. See Appendix D for summary of EPA's review.
Detailed information on neutralization methods employed by Woodland Pulp and their performance would be needed to evaluate the potential for additional costs related to treatment of acidic effluent. Given the limited information available and evidence that the facility already adjusts pH and achieves levels above 6.5, EPA assumed that any incremental costs would be minimal.
Temperature Criterion for Tidal Waters
MEDEP Chapter 582 establishes a not-to-exceed criterion of 85ºF outside of the discharge mixing zone in marine waters. Maine also limits discharges from causing the monthly mean of the daily maximum ambient temperatures in any tidal waterbody to be raised more than 4ºF at any time, or more than 1.5°F from June 1 to September 1 (summer months). 
In contrast, EPA proposed criteria include a maximum cumulative increase in weekly average temperature from all artificial sources of 1°C (1.8° F) year round, relative to baseline temperature, and provided that the summer weekly maximum of 18°C (64.4° F) is not exceeded; and requires that the natural temperature cycles be maintained. Accordingly, adoption of EPA's proposed temperature criteria could affect discharge permit thermal limits outside of the summer months, particularly because discharge temperatures resulting in a departure of 4°F on a monthly basis would be greater than those associated with a 1.5°F increase on a weekly basis. It would also affect discharges that cause the receiving water to exceed the summer maximum criterion. 
However, only four of the 33 dischargers to waters in Indian lands or their tributaries discharge into tidal or marine waters: Calais School (ME0102765), Washington County Community College (ME0102831), Passamaquoddy POTW (ME0100100773), and Calais POTW (ME0100129). The Calais POTW and the two schools discharge treated sanitary wastewater to the St. Croix River, and the Passamaquoddy POTW discharges to Passamaquoddy Bay. None of the facilities discharge heat. These discharges are not expected to have a noticeable effect on temperatures in the tidal waters near the Pleasant Point Reservation. Based on this assessment, EPA assumed there would be no incremental costs for the proposed temperature criterion for tidal waters.
Mixing Zone
EPA disapproval of Maine's mixing zone policy may affect dischargers for which MEDEP established mixing zones. Compared to the disapproved mixing zone policy, the proposed mixing zone policy provides greater protection for designated aquatic life uses by: 
clarifying the extent to which criteria may be exceeded in a mixing zone; 
specifying that mixing zone must be as small as necessary, and pollutant concentrations must be minimized and reflect the best practicable engineering design of the outfall to maximize initial mixing; 
requiring the use of methodologies in EPA's "Technical Support Document for Water Quality-based Toxics Control"; 
prohibiting the use of a mixing zone for bioaccumulative pollutants and for bacteria; and 
establishing a number of restrictions to protect designated uses, including requirements that the mixing zone not result in lethality to organisms passing through or within the mixing zone, and not endanger critical areas such as breeding and spawning grounds, habitat for threatened or endangered species, and areas with sensitive biota, shellfish beds, fisheries, and recreational areas.
EPA found only one permit that contains adjusted effluent limits based on a mixing zone (Woodland Pulp, with a mixing zone for heat). The implications for that discharger of changes in the mixing zone policy are uncertain, but could include the need to conduct more detailed assessments of thermal impacts, recalculate the spatial or volumetric limitations for the zone of initial dilution (ZID) and thermal mixing zone, and require zones of passage. A smaller available mixing zone resulting from the proposed rule may lead the discharger to seek a CWA section 316(a) thermal variance rather than having to meet otherwise applicable thermal limitations. To support such a variance request, the discharger would need to conduct a section 316(a) Demonstration Study during renewal of the discharge permit. Such field studies can require significant levels of effort. Further, if the thermal effluent variance request is denied, the discharger may be required to upgrade or install new technologies to reduce discharge thermal loading and/or modify discharge conditions or structures. Design, engineering and implementation of such new technologies or adoption of improved operational practices can represent major costs. 
To understand the potential implications for the discharger, EPA reviewed information available for this facility. Exhibit 3-5 summarizes key information regarding the thermal mixing zone at this facility. 
 Exhibit 3-5. Discharger with Thermal Mixing Zone Affecting Waters in Indian Lands 
Facility
Permit Conditions
Woodland Pulp LLC 
(ME 0001872)
1.  Thermal discharge to the St. Croix River with seasonal limits (June 1  -  September 30)
2.  Permit defines a zone of initial dilution (ZID) over a 5.3 mile segment of river (to Baring railroad trestle) and a mixing zone extending 4.0 mile downstream from the edge of the ZID (from Baring railroad trestle to Milltown dam) 
3.  Thermal survey conducted by GPC in 1989 indicated >2[o]F increase below the discharge point. ME Division of Environmental and Assessment (ME DEA) developed QUAL2E model using GPC data to calibrate the model. The model predicted a temperature increase of 1.1[o]F at end of ZID. ME DEA and GPC concurred that separation of discharge impacts from natural diurnal temperature fluctuations was difficult and that it was preferable to establish a formal mixing zone.
4.  The 1996 WDL established the original average and daily maximum thermal load limitations and ZID and thermal mixing zone. 
5.  The 1996 WDL stated that no testing shall be conducted for thermal violations within designated ZID or established mixing zone. The 1996 WDL also contained special conditions requiring the plant to investigate ways to reduce heat loads. 
6.  Four cooling towers were installed in 1997. Plant ceased using two of them in 1998 due to operation and maintenance problems.
7.  2005 permit required continuous in-stream monitoring between June and September but requirements were discontinued in 2012.
8.  Based on its review of the monitoring report for 2012, MEDEP concluded that "the thermal discharge resulted in temperature greater than would be allowed under DEP's temperature rule, if not for the existence of a mixing zone where the rule does not apply"
Sources: 
Woodland Pulp LLC: MEPDES Permit #ME0001872; Maine WDL Application #W002766-5N-J-R, June 28, 2014

Section 4.4 details EPA's analysis of the cost impacts of the proposed mixing zone policy for waters in Indian lands.
Proposed Dissolved Oxygen Criteria for All State Waters
The proposed rule includes the same year-round criteria for Class A fresh waters that Maine uses, but adds more protective DO criteria for spawning areas in winter months. Specifically, the proposed rule requires that the 7-day mean DO concentration be no less than 9.5 ppm (9.5 mg/L), and the 1-day minimum DO concentration be no less than 8 ppm (8.0 mg/L)  --  for spawning areas in winter months.
The proposed rule may potentially affect 26 facilities with draft or final permits to discharge in Class A waters. EPA's review of permits for the 26 facilities affected by the proposed DO criteria shows several facilities for which MEDEP determined a potential for impacts to DO levels in receiving waters and set daily minimum DO concentrations for the effluent. These limits are applicable from June 1[st] to September 30[th]. Because monitoring is limited to the period when the limits apply, no effluent monitoring data for DO were available for winter months. As described in Section 2.2.8, EPA also reviewed ambient monitoring data for Class A waters, but EPA noted that of the 193 samples collected by MEDEP on Class A waters (not all of which would have a permitted discharger), none were collected during the winter months.
According to Maine law, granting of discharge permits in Class A waters is predicated on the discharged effluent being equal to or better than the existing water quality of the receiving water (38 M.R.S §465(2.C)). This requirement means that in cases where ambient water quality is equal to or better than what the proposed criteria would require (i.e., ambient water quality is already above 8.0 mg/L daily minimum and 9.5 mg/L for the 7-day mean) during the winter months, the proposed criteria would not result in incremental costs to the facilities.
As discussed in Section 2.2.8, nonpoint sources are an important contributor to DO impairments by increasing organic loads into the streams. Effects of the proposed DO criteria for winter months on these nonpoint sources are difficult to assess given the lack of existing data. EPA assumed that these effects would be minimal given the limited scope of the proposal to Class A waters. 
Proposed Phenol Criteria for State Waters Outside of Indian Lands
EPA disapproved the criterion for phenol (for the consumption of water and organisms), which was 10,514 ug/l, for Maine waters outside of Indian lands due to a mathematical error. EPA's proposed criterion of 4,000 ug/L corrects the mathematical error and is based on EPA's 2015 national recommended criterion but adjusted to use Maine's FCR of 32.4 g/day. 
Very little data are available on ambient concentrations or discharges of phenol in Maine waters. Public data sources EPA reviewed showed no analytical results for phenol in surface waters. EPA's DMR data list only two facilities in Maine (Brunswick Graham Rd Landfill (ME0102113) and Presque Isle Landfill (MEU508088)) that monitor for, and report, total phenols in their effluent. Of these two dischargers, only the Brunswick Graham Rd Landfill facility had non-zero concentrations. The reported maximum effluent concentration (MEC) for this facility was 2.1 ug/L, which is below both the baseline and proposed criteria before accounting for dilution. 
Based on this information, EPA concluded that the proposed criterion is unlikely to result in incremental costs. 

Method for Estimating Potential Costs: Point Sources
This section describes the method for estimating the potential costs to point sources associated with compliance with the proposed criteria, including available data. Compliance costs for municipal and industrial point sources may result from changes to MEPDES permit requirements and associated effluent limitations. As discussed in Section 3, proposed criteria for pH and temperature (for waters in Indian lands), proposed criteria for phenol (for state waters outside Indian lands) and proposed criteria for DO (for all state waters) are not expected to result in incremental costs to permitted dischargers. The cost analysis, therefore, focuses specifically on the impacts of:
proposed HHC for waters in Indian lands (Section 4.1), 
proposed bacteria criteria for waters in Indian lands (Section 4.2),
proposed aquatic life ammonia criteria for waters in Indian lands (Section 4.3), and 
proposed mixing zone policy for waters in Indian lands (Section 4.4).
EPA notes that the analysis is based on information from publicly available data, permit fact sheets, and priority pollutant scans conducted in accordance with existing permits. While the analysis generally follows the approach a permit writer would use to evaluate and set discharge permit conditions, reliance on available data involves uncertainty and limitations not present during actual permit development, such as more site-specific data (e.g., ambient water quality samples, priority pollutant scans using lower detection limits). See Section 6.3 for further discussion of the uncertainty associated with the use of existing data. 
Except as otherwise noted, the assumed life of capital investments is 20 years, and EPA used a discount rate of 3 percent for the main analysis. Results using a 7 percent discount rate are provided in Appendix E.
Costs from Proposed Human Health Criteria for Waters in Indian Lands 
EPA estimated costs to municipal and industrial dischargers under the proposed criteria by estimating costs to each of the 33 facilities that discharge to waters in Indian lands or their tributaries. This section describes the reasonable potential analysis, identification of limits under the proposed criteria and comparison to baseline criteria, and estimation of costs to meet proposed criteria. 
Unless otherwise noted, EPA updated all cost estimates to 2014 dollars.
Dischargers to Waters in Indian Lands or Tributaries
Factors that may affect the potential magnitude of compliance costs include effluent flow and type of facility. Larger flows are typically associated with the largest treatment costs, although per-unit costs may decrease due to economies of scale. A facility's industrial category may also be indicative of the potential to incur costs. 
As described in Section 1.2, EPA determined that 33 facilities (major and non-major) discharge to waters in Indian lands or their tributaries. Exhibit 4-1 provides a summary of the facilities that discharge to waters in Indian lands or their tributaries. Appendix A provides additional information on these facilities.
EPA notes that almost all (29) facilities discharge to fresh waters, to which the proposed HHC for the consumption of water and organisms would apply. Some of these facilities discharge directly to the waters in Indian lands to which EPA's proposed criteria would apply. Many of the facilities, however, discharge upstream of the waters in Indian lands (including tributaries of such waters), and limits on those discharges would need to ensure that EPA's proposed criteria are met at the boundary of the waters in Indian lands, not at the point of discharge. Four facilities discharge to estuarine or marine waters, to which the HHC for the consumption of organisms only would apply. Only one of these (the Passamaquoddy POTW) discharges directly to waters in Indian lands to which EPA's proposed criteria would apply. The other three facilities (Calais School, Calais POTW, and Washington County Community College) discharge to the St Croix River significantly upstream of the waters in Indian lands at Pleasant Point. 
Exhibit 4-1. Summary of Dischargers to Waters in Indian Lands or Their Tributaries
MEPDES Number
Facility Name
Facility Type
Receiving Surface Waters (Class)
Permitted Monthly Average Flow (MGD)
ME0101320
Baileyville POTW
POTW
St. Croix River (C)
0.6
ME0102784
Brownville
POTW
Pleasant River (B)
                                   no limit
ME0100129
Calais POTW
POTW
St. Croix River (SC/C[2])
1.5
ME0102765
Calais School
Other (school)
Penobscot River (SC)
0.013
ME0001104
Cobb State Fish Hatchery
Other (fish hatchery)
Cold Stream (A)
5.0
ME0023213
Covanta Maine
Industrial (biomass energy)
Penobscot River (B)
0.189
ME0036528
Dolby Hydro Project
Industrial (hydroelectric)
West Branch of the Penobscot River (C)
0.365
ME0102229
Dover-Foxcroft Water District
Utility (drinking water treatment)
Piscataquis River (B)
0.15
ME0100501
Dover-Foxcroft WWTP
POTW
Piscataquis River (B)
0.8
ME0036511
East Millinocket Hydro Project 
Industrial (hydroelectric)
Penobscot River (C)
0.3024[1]
ME0000175
East Millinocket POTW
POTW
Penobscot River (C)
2.0
ME0036625
Eustis Hydro Project
Industrial (hydroelectric)
North Branch Dead River (A)
0.0072[1]
ME0001082
Grand Lake Stream Fish Hatchery
Other (fish hatchery)
Grand Lake Stream (A)
2.9
ME0102032
Guilford-Sangerville WWTF
POTW
Piscataquis River (B)
0.465
ME0101290
Houlton WWTF
POTW
Menuxdekeag River (B)
1.5
ME0036633
Howland Hydro Project
Industrial (hydroelectric)
Piscataquis River (B)
0.0014
ME0101788
Howland POTW
POTW
Penobscot River (B)
0.30
ME0101796
Lincoln Sanitary District
POTW
Penobscot River (B)
1.07
ME0036552
Mattaceunk Hydro Project
Industrial (hydroelectric)
Penobscot River (C)
0.144[1]
ME0102245
Mattawamkeag WWTF
POTW
Penobscot River (B)
0.09
ME0102695
Milford
Utility (combined sewer overflow)
Penobscot River (B)
                                  unspecified
ME0037371
Millinocket Hydro 
Industrial (hydroelectric)
West Branch of the Penobscot River (C)
0.022
ME0100803
Millinocket POTW
POTW
West Branch of the Penobscot River (C)
1.34
ME0100439
Milo POTW
POTW
Piscataquis River (B)
0.39
ME0102211
Passamaquoddy Water District
Utility (drinking water treatment)
Boydon Stream (B)
0.045
ME0100773
Passamaquoddy Tribal Council
POTW
Passamaquoddy Bay (SB)
0.15
ME0101311
Penobscot Indian Nation
POTW
Penobscot River (B)
0.1
ME0002216
Tate and Lyle Ingredients
Industrial (food manufacturer)
Menuxdekeag River (B)
0.04
ME0102831
Washington County Community College
Other (college)
St. Croix River (SB)
0.0105
ME0036668
West Enfield Hydro Project
Industrial (hydroelectric)
Penobscot River (B)
0.403
ME0036668
Woodland Hydro
Industrial (hydroelectric)
St. Croix River (C)
0.194
ME0001872
Woodland Pulp
Industrial (pulp mill)
St. Croix River (C)
30
ME0022063
Woodland Pulp: North Site
Industrial (logging)
St. Croix River (C)
16.16
MGD = million gallons per day
POTW = publicly owned treatment works
WWTP = wastewater treatment plant
STP = sewage treatment plant
 1. The flow is a design maximum rather than an average monthly flow limitation.
 2. This permit authorizes discharges from the Calais POTW and four combined sewer overflows (CSOs) to Class SC waters and one CSO to Class C waters.

Reasonable Potential Analysis
For each facility, EPA conducted a reasonable potential analysis to determine whether there is reasonable potential for the effluent to cause or contribute to a water quality violation for any of the pollutants for which EPA is proposing new criteria. For consistency with state implementation procedures, EPA determined reasonable potential using an approach that is consistent with the procedures described in 06-096 CMR 530(3)(E) and U.S. EPA (1991); Section 3.3.2 and Table 3-2), as well as EPA's NPDES Permit Writer's Manual (U.S. EPA, 2010a), and reflecting the fact that, in some cases, the proposed criteria would not apply to the immediate receiving waters but instead would apply to waters in Indian lands downstream from the receiving waters.
EPA conducted the reasonable potential analysis for each proposed criterion and facility, using the last five years (October 2010 to October 2015) of priority pollutant scan monitoring data. Since these data are more recent than the effluent monitoring data used to establish limitations in the facilities' existing permits, it is possible for EPA's reasonable potential analysis to indicate reasonable potential under the baseline criteria even when there is no permit limit. However, as shown in the analyses for each permitted facility in Appendix A, there were no such cases. 
Effluent monitoring data are a key input for determining reasonable potential. There were not sufficient and adequate data available for all facilities to perform reasonable potential analyses for all pollutants for which HHC are proposed. For example, MEDEP requires annual priority pollutant scans for only nine facilities out of the 33 facilities that discharge to waters in Indian lands or their tributaries. The remaining 24 facilities do not have monitoring requirements due to the facility classification or the nature of the discharge. Appendix A summarizes the status of these 24 facilities in more detail. Additionally, for the nine facilities with priority pollutant scan requirements, the associated scan reports did not provide data for all pollutants for which EPA is proposing HHC. 
EPA did not assess reasonable potential for pollutants for which data were unavailable. Instead, EPA assumed that the facilities do not have the potential to discharge pollutants in quantities that could lead to exceedances of HHC. EPA considers this assumption to be reasonable given the rationale provided by MEDEP in permit fact sheets for not requiring monitoring in the first place; specifically the expectation that discharges from each of these facilities were unlikely to contain priority pollutants. While this determination was based on the potential to exceed Maine's baseline HHC, EPA assumes that the same conclusion would be reached when considering the potential to exceed the proposed criteria. Additional data would be needed to confirm or refute this finding under the proposed rule. EPA recognizes that this assumption does not account for the possibility of a pollutant being present in quantities below the reporting levels but above the proposed criteria.
For each facility with priority pollutant scan data available in the last five years, EPA identified each relevant pollutant that had at least one detected value (i.e., a measured concentration above the lab detection level). For the purpose of this analysis, for pollutants with only non-detects EPA assumed no reasonable potential, whereas for pollutants with at least one detected value, EPA assumed the value of any non-detects equal to half the detection limit stated in the scan report. EPA then calculated the number of observations and maximum and average effluent concentrations. 
To determine whether a facility would have reasonable potential to exceed the proposed criteria for a pollutant, EPA multiplied the maximum concentration by a multiplier from US EPA (1991; Table 3-2; determined based on the number of observations and the coefficient of variation) and divided by the facility-specific harmonic mean dilution factor. As discussed earlier, the reasonable potential was evaluated at the point where the proposed criteria apply, i.e., the point where the discharge reaches waters in Indian lands, which may be downstream from the immediate receiving waters. For each facility, EPA determined whether the immediate receiving waters are in Indian lands, and if not, EPA obtained flow information for waters in Indian lands downstream from the discharge location and used the data to calculate the concentrations at that location. For example, for facilities discharging to the Piscataquis River, EPA determined whether the discharge would have reasonable potential to cause an exceedance above the proposed criteria at the confluence of the Piscataquis and Penobscot rivers, where flows from the Piscataquis River enter waters in Indian lands.
EPA added each facility's expected contribution to background concentrations present in the receiving water to calculate the total receiving water concentration (RWC), as shown in the equation below. To determine whether the facility would have reasonable potential to exceed a particular proposed criterion, EPA compared the RWC to the assimilative capacity of the receiving water, which was based on the proposed criterion and the receiving water mean harmonic flow. If the RWC exceeded the assimilative capacity, then the facility would have reasonable potential for that pollutant.
RWC=FlowR  x ConcR+FlowF  x ConcF xMult(FlowR+ FlowF)
where:
    RWC	=	The receiving water concentration including the background concentration and the facility's contribution (ug/L)
    FlowR	=	The harmonic mean flow of the receiving water in Indian lands (MGD) upstream of the discharge
    ConcR	=	The background concentration in the receiving water (upstream of discharge) (ug/L)	
    FlowF	=	The facility average flow limitation (MGD)
    ConcF	=	The facility's maximum effluent concentration (ug/L)
    Mult	=	Multiplier from U.S. EPA (1991); based on number of observations and coefficient of variation
The RWC reflects the contribution of an individual facility to the receiving water. However, in some cases multiple dischargers affect the same water. In those cases, EPA evaluated reasonable potential to exceed the proposed criteria by accounting for the cumulative impacts of discharges. For example, if two dischargers that are very close to each other both discharge a particular pollutant, EPA allocated a share of the receiving water's assimilative capacity for that pollutant to each facility (based on historical average loading). In other cases, a facility's effluent may mix with that of other facilities further downstream; in such cases EPA also evaluated reasonable potential cumulatively at the most downstream location along waters in Indian lands. The equation below shows how EPA calculated the share for each facility.
Sharei=Flowi*Concii=1nFlowi*Conci 
where:
    Sharei  	=	The share of the receiving water assimilative capacity for the pollutant that is allocated to facility i
    Flowi	=	Monthly average flow limitation for facility i
    Conci	=	Average effluent concentration of the pollutant for facility i
    n		= 	Number of facilities discharging the pollutant to the given receiving water
Exhibit 4-2 illustrates this by showing facilities discharging to the Penobscot River or its tributaries upstream of Indian Island. For these facilities, EPA looked at the potential for any individual facility to exceed the proposed criteria at the point where its flow enters Indian lands (either at the point of discharge for facilities on the Penobscot River, or at the confluence of the Piscataquis River and the Penobscot River for facilities on the Piscataquis River), as well as the potential for the combination of all dischargers to exceed the proposed criteria at the location of the most downstream facility on the Penobscot River (e.g., Penobscot Housing Indian Island) discharging the pollutant of concern. In both cases, EPA considered the cumulative impact of the discharger's effluent combined with the effluent of all upstream dischargers.
Exhibit 4-2: Facilities discharging to the Penobscot River in Indian lands or its tributaries.

Note that EPA's approach for determining reasonable potential increases the likelihood of finding reasonable potential and setting more stringent effluent limits, relative to MEDEP's procedure. 
According to 06-096 CMR 530(3)(F)(3), if all values are below Maine's reporting limits, then the facility is deemed to have no reasonable potential to exceed criteria. However, in many cases, actual laboratory detection levels are more sensitive than Maine's reporting limits. For this analysis, EPA used the laboratory's stated detection limit in lieu of Maine's reporting limit to determine reasonable potential. 
Additionally, it is unclear whether MEDEP typically includes consideration of background concentrations in determining reasonable potential. None of the permits reviewed in preparing this Economic Analysis discussed the background concentrations for toxic pollutants (although several permits did account for background nutrient concentrations). For the purpose of this analysis, EPA incorporated consideration of the background concentration of pollutants when comparing facility contributions to receiving waters. In the absence of monitoring data for reference sites, for the purposes of this report, EPA followed Maine's practice (see 06-096 CMR 530(4)(C)) of assuming background levels equal to 10 percent of the criteria. This assumption tends to overstate the potential for exceeding the water quality criterion, relative to assuming no background level. 
Appendix A provides facility-specific reasonable potential results under the baseline and proposed rule scenarios and additional information on the specific data sources used for each facility. Exhibit 4-3 summarizes, for each facility, the pollutants with detected effluent data (i.e., the pollutants for which EPA conducted a reasonable potential analysis), and the pollutants for which EPA determined that the facility has reasonable potential to exceed baseline or proposed criteria for waters in Indian lands. One facility has a reasonable potential to exceed one proposed criterion. 
Exhibit 4-3. Summary of Dischargers with Detected Effluent Data and Reasonable Potential Analysis
MEPDES Number
Facility Name
Pollutants with Detected Effluent Data Available[1]
Pollutants with Reasonable Potential
ME0101320
Baileyville POTW
Mercury
None
ME0102784
Brownville
None
None
ME0100129
Calais POTW
Cyanide, dichloro-bromomethane, mercury, toluene
None
ME0102765
Calais School
None
None
ME0001104
Cobb State Fish Hatchery
None
None
ME0023213
Covanta Maine
None
None
ME0036528
Dolby Hydro Project
None
None
ME0102229
Dover-Foxcroft Water District
None
None
ME0100501
Dover-Foxcroft WWTP
Mercury
None
ME0036511
East Millinocket Hydro Project
None
None
ME0000175
East Millinocket POTW
None
None
ME0036625
Eustis Hydro Project
None
None
ME0001082
Grand Lake Fish Hatchery
None
None
ME0102032
Guilford-Sangerville WWTF
Antimony, mercury, phenol
None
ME0101290
Houlton WWTF
Mercury
None
ME0036633
Howland Hydro Project
None
None
ME0101788
Howland POTW
Mercury
None
ME0101796
Lincoln Sanitary District
Cyanide, mercury 
None
ME0036552
Mattaceunk Hydro 
None
None
ME0102245
Mattawamkeag
None
None
ME0102695
Milford
None
None
ME0037371
Millinocket Hydro 
None
None
ME0100803
Millinocket POTW
Mercury
None
ME0100439
Milo POTW
Mercury
None
ME0100773
Passamaquoddy
None
None
ME0101311
Penobscot Indian Nation
Mercury
None
ME0002216
Tate and Lyle Ingredients
Bis(2-ethylhexyl) phthalate, cyanide, mercury
Bis(2-ethylhexyl)phthalate (proposed criteria) 
ME0102831
Washington County Community College
None
None
ME0036668
West Enfield Hydro Project
None
None
ME0036668
Woodland Hydro
None
None
ME0001872
Woodland Pulp
Mercury
None
ME0022063
Woodland Pulp: North Site
None
None
1. Pollutants for which there was at least one detected value in priority pollutant scan data (if required) between October 2010 and October 2015.

Projecting Effluent Limitations
There is one facility, Tate and Lyle Ingredients, that has a reasonable potential to exceed the proposed criteria and may require more stringent effluent limitations for one pollutant (bis(2-ethylhexyl)phthalate). EPA calculated an average monthly effluent limitation (AMEL) based on procedures described in 06-096 CMR 530(3) and 06-096 CMR 530(4). For a detailed description of the assumptions and methodologies used, see Appendix A.
First, EPA calculated the assimilative capacity (in pounds per day) of the receiving water based on the harmonic mean flow and the applicable HHC. Before allocating the assimilative capacity to the discharger, MEDEP accounts for background concentrations using site-specific data, listed default background conditions for a particular region, watershed, or statewide basis, or some other method. The permit fact sheet for Tate and Lyle Ingredients states that, lacking information about background conditions, MEDEP applies a default background concentration of 10 percent of the applicable criterion, and EPA used this same assumption in this analysis to calculate effluent limits.
Additionally, MEDEP holds a portion of the total assimilative capacity in an unallocated water quality reserve to allow for new or changed discharges and nonpoint source contributions. According to 06-096 CMR 530(4)(E), this reserve amount must be no less than 15 percent of the total assimilative quantity. The Tate and Lyle Ingredients permit fact sheet states that MEDEP applies a 15 percent reserve in establishing effluent limitations, and EPA used this same assumption in this analysis to calculate effluent limits. After accounting for the 10 percent background and 15 percent reserve allocations, 75 percent of the receiving water's assimilative capacity is available to allocate to the discharger. 
EPA calculated a pollutant allocation based on the receiving water assimilative capacity minus the background and reserve. This facility allocation represents the pounds per day that the facility is allowed to discharge to the waterbody. EPA then calculated the AMEL by dividing the allocation by the monthly average flow limitation (in MGD) and converting from pounds per million gallons to ug/L. Using this approach, EPA calculated a bis(2-ethylhexyl)phthalate AMEL for Tate and Lyle Ingredients of 17.675 ug/L, which represents a reduction from the facility's maximum concentration of 32 ug/L. 
Identifying Compliance Scenarios and Costs
Analysis of the available data for the facilities indicates that there is likely to be exceedances of the projected effluent limit for bis(2-ethylhexyl)phthalate (i.e., instances where the facility will need to reduce effluent concentrations to meet the projected effluent limits under the proposed criteria) for one facility. There are a number of potential alternatives for compliance with effluent limits for this pollutant, including:
Process optimization;
Source control (e.g., P2 program);
Installing end-of-pipe treatment technology (e.g., granular activated carbon (GAC)); and
Alternative compliance mechanisms (e.g., site-specific criterion, TMDL, or variance).
In theory, dischargers will pursue the lowest cost means of compliance with effluent limitations. 
Process Optimization
The lowest cost option is likely the adjustment of existing treatment (process optimization). This option would be most feasible when relatively low pollutant reductions are needed or monitoring data indicate that pollutant loads increase throughout the treatment process as a result of chemical additions or treatment techniques. 
Process optimization usually involves process analysis and process modifications. Process analysis is an investigation of the performance-limiting factors of the treatment process and is a key factor in achieving optimum treatment efficiency. Performance-limiting factors for common wastewater treatment processes may include operator training, response to changes in wastewater quality, maintenance activities, automation, and process control testing. The cost of process analysis includes the cost of additional or continuous monitoring throughout the treatment process and a treatment performance evaluation. These costs vary based on the number of treatment processes utilized and the magnitude of the reductions needed. 
Process modifications include activities short of adding new treatment technology units (conventional or unconventional) to the treatment train. For increasing pollutant removal efficiencies, process modifications could include adjusting coagulant doses to increase settling, equalizing flow if pollutant concentrations spike during  particular times, increasing filter maintenance activities or backwash cycles, training operators, and installing automation equipment including necessary hardware and software. Several months of adjustments may be needed to achieve a desired level of process optimization. In practice, the process modifications necessary would be determined by the process analysis study.
The effectiveness of process optimization largely depends on the efficiency of current operations, the pollutant needing reductions, the existing treatment processes, and the fate and transport of the pollutant through the treatment train. For example, if a facility is already well maintained and operated, implementing process optimization may not result in sufficient pollutant reductions because the existing treatment processes are already performing at feasible limits. Also, because the design of most conventional treatment technologies maximizes removal of suspended solids, process optimization aimed at increasing those removal efficiencies may not result in sufficient reductions for pollutants existing primarily in dissolved form. Given the available information, it is generally not possible to determine the reductions achievable with process optimization; rather, a detailed, site-specific study would be necessary. Therefore, EPA did not estimate costs for process optimization among the compliance strategies considered in this analysis. 
Source Controls
If adjusting existing operations would not be feasible or would not be sufficient to achieve the necessary reductions, source controls would likely be the next most cost-effective control option. Source control could be used alone, or in conjunction with process optimization. The feasibility of source control efforts depends on the makeup of the influent and potential sources of the pollutant. In the case of wasted industrial ingredients or chemical byproducts, such as bis(2-ethylhexyl)phthalate, it is possible that the production process could be adjusted to use or generate a smaller waste stream of the pollutant. 
P2 programs can be a cost-effective means of reducing toxic pollutants in wastewater effluents. However, as contributing sources are identified and controlled, the cost-effectiveness and efficacy that a P2 program would provide will diminish, and a discharger may need to pursue alternative compliance mechanisms (i.e., a variance) if compliance with permit conditions has not been achieved. Successful P2 programs will likely include at least some of the following steps:
Identify sources;
Define program goals  -  including a statement of how the facility intends to reduce pollutant levels in its effluent, the purpose for doing so, and a time line for completion;
Develop an approach  -  including selecting sources for P2 efforts and targets (e.g., size of the source loading, time required to produce desired results);
Estimate program costs;
Implement program  -  starting with the most cost-effective measures and modifying activities and approach based on measured results;
Assess progress; 
Provide follow-up; and
Develop a contingency plan  -  including a description of actions to be taken if planned efforts are unsuccessful.
P2 plans vary in complexity and in the resources necessary to achieve the goals set forth. To estimate costs, EPA relied on estimates previously developed for the economic analysis of WQS for the State of Oregon (U.S. EPA, 2008). EPA escalated these costs to 2014 dollars using the Consumer Price Index (CPI), resulting in estimated costs of $28,000 per year for the individual industrial discharger.
End-of-Pipe Treatment
For end-of-pipe treatment for bis(2-ethylhexyl)phthalate, EPA assumed that the facility would use GAC treatment, which is capable of reliably controlling this pollutant at levels below the projected effluent limits. EPA estimated the costs for GAC treatment using its WBS cost model for GAC treatment of drinking water (model release date August 12, 2014). The WBS model for GAC treatment is a spreadsheet-based engineering model that divides the treatment process into discrete components in order to build up a cost estimate, as described in more detail in Khera et al. (2013) and U.S. EPA (2014a). 
To apply the WBS model for GAC treatment in this analysis, EPA selected facility- and pollutant-specific inputs and assumptions as documented in Appendix A. Because the model estimates costs in 2013 dollars, EPA escalated the model output capital costs and operating costs to 2014 dollars using the Engineering News-Record construction cost index (ENR CCI) and CPI, respectively. EPA annualized all capital costs over 20 years using a 3 percent discount rate (see Appendix E for results using a 7 percent discount rate).
EPA designed the WBS model for GAC to estimate costs for drinking water, not wastewater, treatment. However, the process equipment needed for GAC treatment of wastewater is essentially the same as that required for drinking water. Also, although the model allows for the input of site-specific data and assumptions (such as flow rates and operating parameters), its primary purpose is to generate national average costs. Thus, although EPA selected facility-specific inputs and assumptions for this analysis (as documented in Appendix A), the model outputs rely on national average, not facility- or region-specific, unit costs (e.g., equipment prices, labor rates). Because of these limitations, the GAC treatment cost estimates presented here should be considered order-of-magnitude estimates, not definitive facility-specific estimates.
Alternative Compliance Mechanisms
If GAC treatment discussed above would not result in compliance with revised effluent limitations, or if the costs of this technology would be prohibitive, the discharger would likely need some form of relief from the requirements. Alternative compliance mechanisms that can offer some form of relief can include site-specific criteria, designated use removal or modification, and variances. EPA included the costs of obtaining variances among the compliance strategies considered in this analysis. Data were not available to evaluate the applicability or cost of other alternative compliance mechanisms.
To estimate costs for a variance, EPA relied on estimates previously developed for economic analysis of WQS for the State of Oregon (U.S. EPA, 2008). EPA escalated these costs to 2014 dollars using the CPI, resulting in an estimated one-time cost of $180,000. EPA annualized these costs over 20 years using a 3 percent discount rate (see Appendix E for results using a 7 percent discount rate).
Costs from Proposed Bacteria Criteria for Waters in Indian Lands
As discussed in Section 3.1.2, while the proposed bacteria criteria for waters in Indian lands are not expected to result in treatment processes being added to facilities, year round applicability of the criteria will require facilities to operate disinfection systems year round  rather than for a fraction of the year as currently done. Accordingly, EPA estimated potential costs for the proposed criteria based on typical disinfection costs for POTWs based on the effluent flow rate and type of treatment (chlorination/dechlorination), and monitoring costs. 
Fifteen of the 33 facilities discharging to waters on Indian lands have existing limitations for bacteria. Exhibit 4-4 identifies these facilities, along with information from their permits on their current disinfection and, where applicable, dechlorination practices.
Exhibit 4-4. Summary of Current Disinfection and Dechlorination Practices at Facilities with Bacteria Limitations
                                 Facility Name
                          Current Disinfection Method
                         Current Dechlorination Method
Baileyville
Sodium hypochlorite
Sodium bisulfite
Calais POTW
Sodium hypochlorite
None
Calais School
Unspecified chlorination
No information
Dover-Foxcroft WWTF
Sodium hypochlorite
Sodium bisulfite
Guilford-Sangerville Sanitary District
Sodium hypochlorite
Sodium bisulfite
Houlton POTW
Sodium hypochlorite
Sodium bisulfite
Lincoln Sanitary District
Sodium hypochlorite
No information
Millinocket POTW
Sodium hypochlorite
No information
Milo WWTF
Sodium hypochlorite
Sodium bisulfite
Passamaquoddy Tribal Council POTW
Unspecified chlorination
Unspecified dechlorination
Penobscot Indian Nation WPCF
Sodium hypochlorite
No information
Town of Brownville Subsurface WWTF
None[1]
None
Washington Comm. College
Calcium hypochlorite[2]
None
East Millinocket POTW
Unspecified chlorination
No information
Howland WWTF
Sodium hypochlorite
No information
1. It appears this facility is able to meet its seasonal bacteria limitations without disinfection.
2. Based on description of the disinfection process as a "chlorine tablet" system.

EPA estimated potential costs associated for the proposed criteria assuming facilities would extend the operation of their current disinfection processes year-round. The permits for three facilities (Calais School, Passamaquoddy Tribal Council POTW, and East Millinocket POTW) identified chlorination as the disinfection method, but did not identify the chemical source of the chlorine (e.g., elemental chlorine gas, sodium hypochlorite, calcium hypochlorite). EPA assumed these facilities currently use sodium hypochlorite, based on the typical practice at the majority of facilities that identified the chlorination chemical. EPA used the following assumptions to estimate incremental costs associated with extended operation of disinfection processes:
Because no information was available on the chlorine dosage used at any of the facilities, EPA developed upper- and lower-bound estimates assuming chlorine doses of 20 mg/L and 5 mg/L, respectively, based on the typical range for POTWs of 5 to 20 mg/L (U.S. EPA, 1999).
EPA used a price of $2.26 per gallon for sodium hypochlorite solution of 12.5 percent strength as chlorine, based on data from EPA's WBS model for GAC. 
EPA used a price of $1.29 per pound for dry calcium hypochlorite with 65 percent availability as chlorine, also based on data from EPA's WBS model for GAC. 38
EPA also assumed that facilities that currently dechlorinate their effluent would extend the operation of dechlorination processes year-round. As shown in Exhibit 4-4, six of the facilities are known to dechlorinate. The permit for Passamaquoddy indicated that the facility dechlorinates, but did not identify the method used. EPA assumed this facility uses sodium bisulfite, based on the typical practice at the majority of facilities that identified the dechlorination chemical. The permits for an additional six facilities (see Exhibit 4-4) did not provide information on whether or not dechlorination is currently required. In its upper-bound estimate, EPA included dechlorination costs for twelve facilities (the six known to dechlorinate, plus the six where current dechlorination practices are unknown). In its lower-bound estimate, EPA included dechlorination costs only for the six facilities known to dechlorinate currently. EPA used the following assumptions to estimate incremental costs associated with extended operation of dechlorination processes:
Because no information was available on the dechlorination dosage used at any of the facilities, EPA assumed a sodium bisulfite dose of 4.38 mg/L, based on a need to neutralize 3 mg/L excess residual chlorine and 1.46 parts sodium bisulfite per part residual chlorine (U.S. EPA, 2000).
EPA used a price of $2.30 per gallon for 38 percent sodium bisulfite solution, based on data from EPA's WBS model for GAC. 38
EPA assumed disinfection and dechlorination processes would operate for an additional 226 days per year, based on extending operation during October 1 through May 14. EPA did not include incremental costs for operating labor, maintenance materials, or electricity associated with extended operation of the processes, because these costs would be expected to be minimal in comparison to chemical costs. Finally, EPA included costs for seven additional monthly bacteria analyses, using a laboratory cost of $45 per analysis (Maine Water, 2012; online price assumed to be current). EPA assumed there would be no incremental costs for collection or shipping of the samples, beyond the existing costs for other monthly sampling during these seven months. EPA also assumed no one-time or capital costs would be incurred (i.e., that extending the period of disinfection and dechlorination would not require any upgrades to physical equipment). Therefore, the resulting costs are already in annual terms and unaffected by the discount rate (i.e., 3 percent or 7 percent).
Costs from Proposed Ammonia Criteria for Waters in Indian Lands 
EPA used a similar approach to that used for HHC to identify the dischargers with reasonable potential for exceedances of the proposed ammonia criteria. The AWQC depends on both temperature and pH. To assess reasonable potential, EPA used a threshold of 1.4 mg/L N, which corresponds to the proposed chronic ammonia criterion for a water temperature of 25ºC and pH of 7.0 SU and is consistent with the approach used by MEDEP in setting effluent limits in existing discharge permits that address ammonia. Note that at the colder water temperature typical of Maine waters outside of summer months, the criterion value is higher (see Exhibit 3-4). 
As discussed in Section 3.1.3, ammonia monitoring data for the last five years (October 2010 through October 2015) are available for 9 of the 33 facilities discharging to waters in Indian lands or their tributaries. Exhibit 4-5 summarizes available ammonia effluent data for these facilities. 
Exhibit 4-5. Summary of Ammonia Effluent Data
Facility[1]
Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Calais POTW
                                                                              2
                                                                               
                                                                            800
                                                                            500
Dover-Foxcroft WWTP
                                                                             15
                                                                            125
                                                                         35,700
                                                                         14,317
Guilford-Sangerville WWTF
                                                                             11
                                                                               
                                                                          5,730
                                                                          2,104
Houlton WWTF
                                                                              9
                                                                            100
                                                                            472
                                                                            197
Lincoln Sanitary District
                                                                              2
                                                                               
                                                                          1,200
                                                                            795
Millinocket POTW
                                                                              6
                                                                               
                                                                         17,500
                                                                         12,062
Milo POTW
                                                                             12
                                                                               
                                                                         19,400
                                                                         13,813
Tate and Lyle Ingredients
                                                                              4
                                                                               
                                                                          9,080
                                                                          2,810
Woodland Pulp
                                                                              9
                                                                               
                                                                         11,200
                                                                          3,122
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only facilities for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified (i.e. all observations were above detection).
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

For each of the facilities with ammonia monitoring data, EPA conducted a reasonable potential analysis to determine whether the facility has reasonable potential to contribute to an exceedance of the baseline or proposed criteria in the receiving waterbody. As with the HHC analysis described in Section 4.1, EPA assessed the reasonable potential based on the cumulative impact of all dischargers to the relevant receiving waters (i.e., waters in Indian lands). 
First, EPA calculated the individual facility contribution to ammonia loadings based on the MEC, a multiplier from U.S. EPA (1991; Table 3-2), and the monthly average flow limitation. Next, EPA calculated the relative share of each facility to ammonia loadings in the waterbody based on historic effluent concentrations and monthly average flow limitations, using the following equation.
Sharei=Flowi*Concii=1nFlowi*Conci 
where:
    Sharei  	=	The share of the receiving water assimilative capacity for ammonia that is allocated to Facility i
    Flowi	=	Monthly average flow limitation for Facility i
    Conci	=	Average effluent concentration of ammonia for Facility i
This calculation yields the facility share of allowable daily ammonia loadings to the waterbody.
Based on the receiving water flow, the criterion, a background concentration of 10 percent of the applicable criterion, and the relative share of loadings for the facility, EPA calculated the amount of ammonia that the receiving water can assimilate daily from each facility while remaining under the applicable criterion. If the facility's calculated contribution exceeds its associated share of the assimilative capacity, then the facility is determined to have reasonable potential to exceed the ammonia criteria. 
Exhibit 4-6 summarizes this reasonable potential analysis. Based on facility effluent concentrations, flow limitations, receiving water chronic flows, and facility allocations, no facility has reasonable potential under baseline or proposed criteria (i.e., all RWC values are less than corresponding assimilative capacity values).
Exhibit 4-6. Summary of Ammonia Reasonable Potential Analysis
Location
(7Q10 Flow)
Facility
RWC (lb/day)[1]
Facility Share[2]
Assimilative Capacity (lb/day)[3]

Proposed
Baseline
Penobscot Upstream 
(1,555 MGD)
Millinocket POTW
                                                                            714
                                                                         100.0%
                                                                         16,226
                                                                         35,021
Penobscot at Lincoln 
(1,824 MGD)
Millinocket POTW
                                                                            714
                                                                          97.1%
                                                                         18,473
                                                                         39,869

Lincoln Sanitary District
                                                                             41
                                                                           2.9%
                                                                            559
                                                                          1,207
Penobscot at Confluence 
(1,961 MGD)
Millinocket POTW
                                                                            714
                                                                          58.9%
                                                                         12,042
                                                                         25,991

Lincoln Sanitary District
                                                                             41
                                                                           1.8%
                                                                            365
                                                                            787

Dover-Foxcroft WWTF
                                                                            429
                                                                          24.0%
                                                                          4,908
                                                                         10,593

Guilford-Sangerville
                                                                             93
                                                                           4.1%
                                                                            838
                                                                          1,809

Milo POTW
                                                                             82
                                                                          11.3%
                                                                          2,308
                                                                          4,982
St. Croix River 
(549 MGD)
Woodland Pulp
                                                                          5,044
                                                                         100.0%
                                                                          5,732
                                                                         12,372
Passamaquoddy Bay 
(24,333 MGD)
Calais POTW
                                                                             38
                                                                           0.8%
                                                                          2,017
                                                                          4,352

Woodland Pulp
                                                                          5,044
                                                                          99.2%
                                                                        251,858
                                                                        543,578
Meduxnekeag River 
(8 MGD)
Houlton
                                                                             11
                                                                          63.7%
                                                                             55
                                                                            118

Tate and Lyle
                                                                             12
                                                                          36.3%
                                                                             31
                                                                             67
1. The facility's receiving water contribution (RWC) is the maximum effluent concentration (converted from ug/L to lbs/gallon based on a conversion factor of 0.00834) times multiplier from US EPA (1991; Table 3-2) times maximum average monthly flow limit.
2. Facility's average concentration (converted from ug/L to lbs/day using a conversion factor of 0.00834) times maximum average monthly flow limit divided by the total ammonia contribution to the waterbody from all sources.
3. Applicable criterion (1.4 mg/L under proposed criterion; 3 mg/L under baseline) minus the background concentration (10 percent of the applicable criterion) converted from mg/L to lbs/gallon (based on a conversion factor of 8.34) times the downstream flow times the facility share. 

Costs from the Proposed Mixing Zone Policy
As discussed in Section 3.1.6, one facility discharging to waters in Indian lands (or their tributaries) has an existing permit that establishes a mixing zone (Woodland Pulp LLC, which has a thermal mixing zone). The impacts of proposed WQS are difficult to predict and will depend on how the policy is implemented for this permit. Possible outcomes include: various revisions to permit conditions that could require recalculating thermal discharge limits; the need for facility-specific studies to define a mixing zone consistent with the proposed mixing zone policy; or changes in the facility processes or operations to reduce the effluent thermal load.
There were too many unknowns for EPA to be able to assess low end of the cost implications of the proposed mixing zone policy. Therefore, to assess potential cost impacts of the proposed mixing zone policy, EPA considered a worst-case scenario in which the facility would need to retrofit cooling towers to meet more stringent thermal limits. 
Specifically, EPA estimated the costs of retrofitting cooling towers at the facility using the same approach from its analysis of the Final Section 316(b) Existing Facilities Rule (U.S. EPA, 2014b) and assuming costs for "difficult" retrofits. In applying that approach in this analysis, EPA approximated the maximum reported intake flow (MRIF; used in calculating the costs) as equal to the total monthly average permitted flows for process and non-cooling water (MGD). EPA annualized all capital costs using a 3 percent discount rate (see Appendix E for results using a 7 percent discount rate), and, consistent with U.S. EPA (2014b), assuming a cooling tower useful life of 30 years.
Exhibit 4-7 presents rough cost estimates for the facility. Total annualized costs are approximately $273,000. Note that the estimates do not account for potential cost savings from water and energy efficiency improvements.
Exhibit 4-7. Estimates of Cooling Tower Retrofit Costs at Facility with Thermal Mixing Zone for Discharges to Waters in Indian Lands or Tributaries 
Facility Name
(Flow Rate)[1]
Cost Component[2]
Estimated Costs (Thousand Dollars)
                                       
                                       
Component Costs (2009$)
Component Costs (2014$)
Annualized Costs (2014$)[3]
Woodland Pulp[4]
(15.0 MGD)
Capital costs[5]
                                                                         $4,281
                                                                         $4,899
                                                                           $243

Fixed O&M costs
                                                                            $13
                                                                            $15
                                                                            $15

Variable O&M costs - chemicals
                                                                            $13
                                                                            $15
                                                                            $15

Variable O&M costs  -  Pump and Fan Power
                                                                             $0
                                                                             $0
                                                                             $0

Total
                                                                           $273
1. Maximum intake flow rate is assumed to be equal to the total monthly average non-contact cooling water flow rate in each permit, assuming that cooling towers would be sized based on that flow.
2. Cost components from U.S. EPA (2014b), Exhibit 8-9. Capital cost = $411/gpm; fixed O&M costs = $1.27/gpm; variable O&M costs for chemicals = $1.25/gpm; Variable O&M costs for pump and fan power = $0.0000237/gpm.
3. EPA annualized capital costs using a 3 percent discount rate (see Appendix E for results using a 7 percent discount rate), and, consistent with U.S. EPA (2014b), assuming a cooling tower useful life of 30 years.
4. Information provided in the 2014 WDL suggests that Woodland Pulp operates two cooling towers of the total four cooling towers constructed at the plant. Accordingly, retrofit costs are expected to be overstated. 
5. EPA notes that the cost estimates for Woodland Pulp are generally consistent with anecdotal information EPA found on the construction costs of the four cooling towers at the Woodland Pulp facility in 1996: $3.5 to $7.2 million (after adjusting to 2014 dollars), as compared to $4.9 million estimated by EPA.

As discussed above, cooling tower retrofits represent an upper bound scenario for potential impacts. The cost estimate for the Woodland Pulp facility may be further overstated since EPA assumed that new cooling towers would be required whereas the plant already has four cooling towers and operates two of these towers. For the purpose of this analysis, EPA assumed that the Woodland Pulp may need to take additional measures to reduce the heat load of its effluent, for which the cost of constructing the cooling towers provides an upper bound. 

Methods for Identifying Potential Costs: Nonpoint Sources
The proposed water quality standards could result in incremental impacts on nonpoint sources of pollution, such as agriculture, urban areas, and forestry, through TMDLs or other pollution cleanup plans. Section 2.1 discusses the nonpoint sources of pollution. Ambient water quality data can be used to determine the impact that the proposed HHC may have on the attainment of the criteria and thus the potential for incremental control strategies and costs for nonpoint sources.
Identifying Exceedances
EPA reviewed the available ambient water quality monitoring data to assess potential incremental exceedances of the proposed WQS. As discussed in Section 2.2, monitoring data for waters in Indian lands are extremely limited. EPA did not find any indication, based on these very limited observations, that existing pollutant levels would exceed the proposed criteria for toxic pollutants, ammonia, or other pollutants.
--------------------------------------------------------------------------------
Identifying Compliance Actions and Costs
EPA does not have data on all pollutants for all waterbodies, or data on the sources of loadings to potentially impaired waterbodies. Additionally, MEDEP recently completed development of a management plan for nonpoint source pollution (see MEDEP, 2014). Reductions in nonpoint source pollution loadings arising from this plan will occur in the absence of the proposed rule and represent baseline requirements. 
If the proposed criteria lead to additional waters being listed on the state's 303(d) list for exceedances of water quality criteria, the magnitude of cost impacts to nonpoint sources depends on the extent to which additional practices are needed for compliance with the proposed criteria in comparison to compliance with baseline criteria. 
If nonpoint sources are the primary cause of some incremental impairments (e.g., DO), then the proposed criteria may result in some state-imposed costs to nonpoint sources, including: 
Agricultural and forest lands  -  sediment and erosion controls beyond those specified under existing state and federal regulations and plans;
Non-MEPDES regulated urban runoff  -  increased or additional nonstructural BMPs (e.g., institutional, education, or P2 practices designed to limit generation of runoff or reduce the pollutants load of runoff); and structural controls (e.g., engineered and constructed systems designed to provide water quantity or quality control). 
Control of nonpoint sources of the pollutants of concern could reduce costs to point sources. In the context of a TMDL, load and wasteload allocations reflecting the sources of the pollutant could result in less stringent limits for point sources than anticipated through the analysis of the facilities as described in Section 4. 
If an additional number of TMDLs are needed under the proposed criteria, there may be an increase in government regulatory costs. EPA (2001b) estimates the average cost to develop a TMDL to be about $27,000 to $29,000, depending on the level of complexity and the extent to which impaired waters are clustered together for TMDL development. 

Potential Compliance Costs
This section summarizes the potential costs to point sources and nonpoint sources, and discusses the limitations and uncertainties associated with the analyses. Except as otherwise noted, the assumed life of capital investments is 20 years, and EPA used a discount rate of 3 percent for the main analysis. Results using a 7 percent discount rate are provided in Appendix E.
Point Sources
As described in Sections 4.1 through 4.4, EPA estimates that one facility may incur some incremental costs to meet the proposed HHC for waters in Indian lands, 14 facilities could incur costs due to proposed bacteria criteria for waters in Indian lands, and one facility could incur costs due to the proposed mixing zone policy. 
Exhibit 6-1 summarizes EPA's estimates of facility-specific compliance costs and the total costs that may result from the proposed HHC. The cost estimates reflect a range of potential compliance scenarios as documented in Section 4.1.4 and Appendix A. The low end of the cost estimates represents P2 measures, while the high end of the cost estimates represents end-of-pipe treatment (GAC). End-of-pipe treatment is included in this report as a worst-case option which would be needed only if these other approaches were likely to be unsuccessful. While EPA has reported this as a range, facilities will have better information and be able to decide. Similar possibilities exist at other facilities as well.
Exhibit 6-1. Summary of Estimated Compliance Costs for Proposed Human Health Criteria for Waters in Indian Lands[1]
Facility Name
Pollutant
Estimated Annual Costs
(Thousands; 2014$)[2]
Tate and Lyle Ingredients
bis(2-exylhethyl)phthalate
                                                                      $28 - $43
Total
--
                                                                      $28 - $43
1. See Section 4.1.4 and Appendix A for a description of the methods and assumptions used to develop the facility-specific cost estimates.
2. One-time costs annualized over 20 years using a 3 percent discount rate; see Appendix A for costs annualized using a 7 percent discount rate.

Exhibit 6-2 summarizes estimates of facility-specific costs and total costs for the proposed bacteria criteria, based on the assumption that facilities would need to disinfect their effluent year-round. The upper-bound estimate includes disinfection at a high chlorine dose and dechlorination at twelve facilities (six known to dechlorinate, plus six where current dechlorination practices are unknown). The lower-bound estimate includes disinfection at a lower chlorine dose and dechlorination at only the six facilities known to dechlorinate currently.  
Exhibit 6-2. Summary of Estimated Compliance Costs for Proposed Criteria for Bacteria[1]
Facility Name
Mean Flow (MGD)
Incremental Annual Cost[2] (thousands; 2014$)

Lower-Bound 
Upper-Bound 
Baileyville
                                                                           0.33
                                                                           $9.0
                                                                          $29.3
Calais POTW
                                                                            0.6
                                                                          $12.6
                                                                          $49.3
Calais School
                                                                       0.004446
                                                                           $0.4
                                                                           $0.7
Dover-Foxcroft WWTF
                                                                           0.29
                                                                           $8.0
                                                                          $25.8
Guilford-Sangerville Sanitary District
                                                                          0.284
                                                                           $7.8
                                                                          $25.2
Houlton POTW
                                                                            1.5
                                                                          $39.9
                                                                         $131.9
Lincoln Sanitary District
                                                                           1.07
                                                                          $22.2
                                                                          $94.2
Millinocket POTW
                                                                           1.34
                                                                          $27.7
                                                                         $117.9
Milo WWTF
                                                                           0.25
                                                                           $6.9
                                                                          $22.2
Passamaquoddy
                                                                           0.15
                                                                           $4.3
                                                                          $13.5
Penobscot Indian Nation WPCF
                                                                          0.057
                                                                           $1.5
                                                                           $5.3
Town of Brownville Subsurface WWTF[3]
                                                                            N/A
                                                                           $0.0
                                                                           $0.0
Washington Comm. College
                                                                       0.003077
                                                                           $0.4
                                                                           $0.5
East Millinocket POTW
                                                                              2
                                                                          $41.2
                                                                         $175.7
Howland WWTF
                                                                          0.152
                                                                           $3.4
                                                                          $13.6
Total
                                                                             --
                                                                         $185.3
                                                                         $705.2
1. See Section 4.2 for a description of methods, assumptions, and uncertainties.
2. No one-time costs are included; costs are calculated directly in annual terms and unaffected by assumptions about the discount rate (i.e., 3 percent or 7 percent).
3. It appears this facility is able to meet its seasonal bacteria limitations without disinfection; accordingly, EPA assumed no additional cost to meet the criteria year-round.

Finally, Exhibit 6-3 summarizes upper bound estimates of facility-specific and total costs related to the proposed mixing zone policy.
Exhibit 6-3. Summary of Upper Bound Estimated of Compliance Costs for Proposed Mixing Zone Policy[1]
Facility Name
Flow Rate (MGD)
Annualized Costs 
(thousands; 2014$)[2]
Woodland Pulp
                                                                           15.0
                                                                           $273
Total (Upper Bound)
                                                                             --
                                                                           $273
1. See Section 4.4 for a description of methods, assumptions, and uncertainties.
2. One-time costs annualized over 30 years using a 3 percent discount rate; for costs annualized using a 7 percent discount rate, see Appendix E.

As summarized in Exhibit 6-4, in total, EPA estimated that point source dischargers may incur costs ranging between $213,000 and $1 million as a result of the proposed rule, depending on compliance approaches for meeting potentially more stringent permit conditions. As discussed throughout the report and highlighted in Section 6.3 below, these costs are subject to significant uncertainty and the estimated range reflects some of this uncertainty. 
Exhibit 6-4. Summary of Estimated Point Source Compliance Costs[1]
Proposed WQS
Annualized Costs (thousands; 2014$)[2]
Human health criteria for waters in Indian lands
$28 
                                       
$43
Bacteria criteria for waters in Indian lands
$185
                                       
$705
Mixing zone policy 
Not Estimated
                                       
$273
Total[3]
$213 
                                       
$1,021
1. Excludes costs for proposed ammonia criteria, for which EPA expects costs to be zero. See Section 4.3.
2. Except as otherwise noted (see Section 4.4 for assumptions regarding expected useful life of cooling towers), one-time costs are annualized over 20 years using a 3 percent discount rate. See Appendix E for results using a 7 percent discount rate.
3. Lower bound of total costs excludes costs associated with the mixing zone policy for which EPA estimated only the upper bound scenario. See Section 4.4 for details. 

--------------------------------------------------------------------------------
Nonpoint Sources
As noted in Section 5, EPA had very limited information with which to assess potential impacts of the proposed criteria on ambient water quality. Given the scope of the proposed rule on certain waters and pollutants (notably toxic pollutants) and existing controls on wide-ranging nonpoint source pollution sources including in state-wide TMDLs, EPA determined that any incremental costs on nonpoint sources are unlikely to be significant.
Uncertainties and Quality Assurance
As noted previously, the proposed rule does not establish any requirements directly applicable to regulated entities or other sources of pollution. State implementation of the proposed rule may result in new or revised MEPDES permit conditions for point source dischargers, and incremental control requirements for nonpoint sources. For point sources, EPA has estimated these impacts as the difference between compliance with permit limits based on the baseline (disapproved) WQS and compliance with permit limits based on the proposed WQS. 
The proposed rule could also result in a need for additional controls on nonpoint sources of pollutant loadings to attain WQS. EPA estimated potential incremental impairments using readily available ambient water quality data. However, data are too limited to identify specific incremental control actions and costs that may be required of nonpoint sources.
Exhibit 6-5 summarizes additional uncertainties and limitations in the analysis.
Exhibit 6-5. Uncertainties in Analysis of Costs
Uncertainty / Assumption
Direction of Effect on Cost Estimate
Notes
Baseline controls
Uncertain
EPA did not conduct extensive site-specific review of facility plans and information for addressing baseline water quality issues; thus, facility analyses could under- or overstate baseline and incremental actions and costs.
Use of models or curve fits to estimate end-of-pipe treatment costs for bis(2-ethylhexyl)phthalate
Uncertain
These cost estimating methods produce estimates that should be order-of-magnitude estimates, not definitive, facility-specific estimates.
No reasonable potential for facilities without effluent monitoring requirements or data
Underestimate
For facilities that do not have effluent monitoring requirements or available data, EPA assumed that they would have no reasonable potential to exceed baseline or proposed criteria, and that they would not incur any costs. 
Use of DCP methodology to estimate concentrations in Passamaquoddy Bay
Uncertain
The DCP methodology provides a rough approximation of mixing and flushing in an estuary based on freshwater inflows. The method assumes complete mixing and steady-state conditions. Actual concentrations near Indian lands at Pleasant Point may be lower or higher than estimated using the DCP, but are expected to be significantly lower than estimated at the point of discharge on the St. Croix River 20-30 miles upstream from Pleasant Point.
Detection limits used in existing priority pollutant scan data
Underestimate
EPA relied on data from existing priority pollutant scans completed by permitted dischargers. Some laboratory detection limits may be insufficiently sensitive to detect pollutants present in the effluent. This may understate reasonable potential for these pollutants with relatively low criteria values.
Cost estimates for bacteria compliance do not include incremental operating labor, maintenance, or electricity costs
Underestimate
These costs are expected to be minimal in comparison to the chemical costs that are included in the estimate.
Use of background concentrations in reasonable potential analyses
Uncertain
EPA assumed background concentrations of 10 percent of the applicable criterion when determining reasonable potential. Actual background concentrations could be higher or lower than the assumed level.
No costs associated with proposed dissolved oxygen criteria
Underestimate
Effluent and ambient monitoring data are not available for DO in winter months, and as such EPA was not able to determine whether any facilities would incur costs to meet more stringent limitations during those months. However, given the limited scope of the proposed DO criteria to Class A waters, EPA assumed the effects would be minimal. 
Flow conditions for establishing effluent limitations
Overestimate
For all facilities, EPA calculated effluent limits and estimated costs based on the most stringent flow conditions (i.e., the flow conditions that allow for the lowest dilution for a facility).
Means of addressing incremental impairments
Overestimate
Under a TMDL, load and wasteload allocations may result in less stringent requirements for point sources if nonpoint sources are the cause of impairments.
  
EPA conducted quality assurance checks on the data, analyses, and results, consistent with the project-specific quality assurance plan. In addition, the Agency followed permit development procedures for determining the reasonable potential and calculating effluent limits to ensure consistency with existing permit conditions in developing the baseline and projecting the potential effects of the proposed rule. EPA also used Maine-specific data sources as available, and for all data entry, EPA confirmed the accuracy of data sources and documentation following procedures described in the quality assurance plans. These procedures include checks on all inputs and calculations, and using multiple approaches to confirm results.

References
Chen, W.F. and J.Y. Richard Liew. 2003. The Civil Engineering Handbook, Second Edition. Boca Raton, FL: CRC Press.
ENSR. 2009. Maine Statewide Bacteria TMDL (Total Maximum Daily Loads). Report # DEPLW-1002. Prepared for the Maine Department of Environmental Protection, August 2009.
Khera, Rajiv, Pat Ransom, and Thomas F. Speth. 2013. Using work breakdown structure models to develop unit treatment costs. Journal AWWA 105(11): E628-E641.
Maine Department of Environmental Protection (MEDEP). 2012. 2012 Integrated Water Quality Monitoring and Assessment Report. DEPLW-1246.
Maine Department of Environmental Protection (MEDEP). 2014. Maine Nonpoint Source Management Program Plan: 2015-2019.
Maine Department of Environmental Protection (MEDEP). 2013. General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems.
Maine Department of Environmental Protection (MEDEP). 2011. Multi-Sector General Permit: Stormwater Discharge Associated with Industrial Activity.
Maine Division of Environmental Health (MEDEH). 2015a. Maine Subsurface Wastewater Team: Home. (available from: http://www.maine.gov/dhhs/mecdc/environmental-health/plumb/index.htm)
Maine Division of Environmental Health (MEDEH). 2015b. About the Subsurface Wastewater Team. (available from: http://www.maine.gov/dhhs/mecdc/environmental-health/plumb/about.htm)
Maine Water. 2012. About Us: Lab Services. (available from: http://www.mainewater.com/en/About%20Us/Lab%20Services.aspx) 
National Oceanic and Atmospheric Administration (NOAA) and Environmental Protection Agency Team on Near Coastal Waters (EPA). 1989. Strategic Assessment of Near Coastal Waters: Susceptibility of East Coast Estuaries to Nutrient Discharges: Passamaquoddy Bay to Chesapeake Bay. Summary Report. June 1989.
United States Census Bureau. 2014. Table PEPANNHU: Annual Estimates of Housing Units for the United States, Regions, Divisions, States, and Counties: April 1, 2010 to July 1, 2014.
United States Census Bureau. 1990. Historical Census of Housing Tables: Sewage Disposal. (available from: https://www.census.gov/hhes/www/housing/census/historic/sewage.html)
United States Environmental Protection Agency (U.S. EPA). 2015a. Human Health Ambient Water Quality Criteria: 2015 Update. (available from: http://water.epa.gov/scitech/swguidance/standards/criteria/current/loader.cfm?csModule=security/getfile&PageID=717763)
United States Environmental Protection Agency (U.S. EPA). 2015b. NLFA Technical Advisories Search. (available from: http://fishadvisoryonline.epa.gov/Advisories.aspx; accessed October 29, 2015)
United States Environmental Protection Agency (U.S. EPA). 2014a. Work Breakdown Structure-Based Cost Models for Drinking Water Treatment Technologies. EPA 815-B-14-007. May.
United States Environmental Protection Agency (U.S. EPA). 2014b. Technical Development Document for the Final Section 316(b) Existing Facilities Rule. EPA 821-R-14-002. May.
United States Environmental Protection Agency (U.S. EPA). 2013. Aquatic Life Ambient Water Quality Criteria for Ammonia  -  Freshwater. EPA 822-R-13-001. April
United States Environmental Protection Agency (U.S. EPA). 2012. Water: Contaminated Sediments. Basic Information. (available from: http://water.epa.gov/polwaste/sediments/cs/aboutcs.cfm)
United States Environmental Protection Agency (U.S. EPA). 2010a. NPDES Permit Writer's Manual. EPA-833-K-10-001.
United States Environmental Protection Agency (U.S. EPA). 2010b. Guidance for Implementing the January 2001 Methylmercury Water Quality Criterion. EPA 823-R-10-001.
United States Environmental Protection Agency (U.S. EPA). 2008. Cost of Compliance with Water Quality Criteria for Toxic Pollutants for Oregon Waters. Prepared by Science Applications International Corporation.
United States Environmental Protection Agency (U.S. EPA). 2002. National Recommended Water Quality Criteria: 2002. Human Health Criteria Calculation Matrix. EPA 822-R-02-012. November.
United States Environmental Protection Agency (U.S. EPA). 2001a. Water Quality Criterion for the Protection of Human Health: Methylmercury. EPA-823-R-01-001. January.
United States Environmental Protection Agency (U.S. EPA). 2001b. The National Costs of the Total Maximum Daily Load Program (Draft Report). EPA 841-D-01-003. August.

United States Environmental Protection Agency (U.S. EPA). 2000. Wastewater Technology Fact Sheet: Dechlorination. EPA 832-F-00-022. September.

United States Environmental Protection Agency (U.S. EPA). 1999. Wastewater Technology Fact Sheet: Chlorine Disinfection. EPA 832-F-99-062. September.
United States Environmental Protection Agency (U.S. EPA). 1991. Technical Support Document for Water Quality-Based Toxics Control. EPA/505/2-90-001.
United States Environmental Protection Agency (U.S. EPA). 1980. Guidelines and Methodology Used in the Preparation of Health Effect Assessment Chapters of the Consent Decree Water Criteria Documents. Federal Register 45: 79347, Appendix 3.

Facility-level Analyses of Implication of Proposed Human Health and Ammonia Criteria 
This appendix provides detailed analyses of the implications of the proposed HHC for facilities that discharge to waters in Indian lands or their tributaries, in alphabetical order. Unless otherwise noted, all information and assumptions are based on information in the facility permits and fact sheets. The methods for the reasonable potential analyses, effluent limitation calculations, and cost estimates are described in Section 4, and are generally consistent with Maine's existing permitting practices. 
EPA determined the reasonable potential and effluent limits based on each facility's water quality impacts on receiving waters in Indian lands both individually, and where multiple facilities discharge to the same waters, cumulatively.
EPA annualized all one-time costs over 20 years using two alternative discount rates: three percent and seven percent. This approach with two discount rates are used in order to comply with EPA's Guidelines for Preparing Economic Analyses.
Baileyville POTW
The Town of Baileyville Publicly Owned Treatment Works (POTW; NPDES permit ME0101320) treats wastewater from 700 residential and commercial customers. There are no significant industrial customers. The facility is authorized to discharge a monthly average flow of 0.60 million gallons per day (MGD), with an actual average (November 2008 through February 2013) of 0.33 MGD. Discharge is to the St. Croix River (Class C). The facility's treatment process is comprised of secondary treatment via a mechanical bar screen, a grit removal system, an oxidation ditch, and two secondary clarifiers. 
The facility has a chronic dilution factor of 917 and a permitted flow of 0.60 MGD; prior testing of the effluent showed no toxic compounds present. As such, this facility is categorized as Level IV and does not have priority pollutant scan requirements besides mercury (as described below). For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Effluent Data
The facility has an interim mercury monthly average effluent concentration limit of 16.6 ng/L, and a monitoring frequency of two tests per year. Exhibit A-1 summarizes the available effluent data.
Exhibit A-1. Summary of Effluent Data: Baileyville POTW
Pollutant
Number of Observations[1]
DL (ug/L)[2]
Effluent Concentrations (ug/L)[3]

Maximum
Average
Mercury
                                       9
                                     0.001
                                     0.006
                                    0.0019
Source: 2013 Permit Attachment B; for the period 2008 to 2012.
1. Number of observations includes results above and below detection levels.
2. DL = detection level; blanks indicate that no detection level was specified.
3. Nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
This facility and Woodland Pulp (Section A.32) both discharge to the St. Croix River, a water in Indian lands. Effluent monitoring data for both facilities show detected levels of mercury. Additionally, the flow meets with discharge from the Calais POTW downstream, eventually reaching Passamaquoddy Bay which is a water in Indian lands at Pleasant Point. As such, EPA conducted the reasonable potential analysis considering the impacts of dischargers to waters in Indian lands, both at the point of discharge (for Baileyville POTW and Woodland Pulp) and cumulatively downstream where the discharges from all three facilities meet in Passamaquoddy Bay. Exhibit A-2 summarizes the load allocation among the facilities based on permitted flows and average effluent concentrations.
Exhibit A-2. Mercury Load Allocation for St. Croix River and Passamaquoddy Bay
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Discharge Point
Woodland Pulp
                                                                           30.0
                                                                        0.00206
                                                                        0.00051
                                                                          98.1%
Baileyville POTW
                                                                            0.6
                                                                        0.00194
                                                                        0.00001
                                                                           1.9%
Total
                                                                              
                                                                              
                                                                        0.00052
                                                                         100.0%
Downstream
Woodland Pulp
                                                                           30.0
                                                                        0.00206
                                                                        0.00051
                                                                          78.7%
Calais POTW
                                                                            1.5
                                                                        0.01033
                                                                        0.00013
                                                                          19.8%
Baileyville POTW
                                                                            0.6
                                                                        0.00194
                                                                        0.00001
                                                                           1.5%
Total
                                                                              
                                                                              
                                                                        0.00065
                                                                         100.0%
1. Based on permit fact sheets.
2. See Exhibit A-1 for Baileyville POTW, Exhibit A-4 for Calais POTW, and Exhibit A-35 for Woodland Pulp.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

At the point of Baileyville POTW's discharge, where its flow enters waters in Indian lands, the St. Croix River has a harmonic mean flow of 1,171 MGD. Downstream in Passamaquoddy Bay, EPA estimated an equivalent receiving water flow of 24,333 MGD (see Appendix C). EPA calculated the river's assimilative mercury capacity from the facility at that point based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-3, the facility has no reasonable potential to exceed the proposed mercury criteria.
Exhibit A-3. Reasonable Potential Analysis for Baileyville POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury, discharge point
                                                                            1.8
                                                                       0.000050
                                                                           1.9%
                                                                       0.000088
                                                                             NA
Mercury, downstream
                                                                            1.8
                                                                       0.000054
                                                                           1.5%
                                                                       0.001469
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration from Exhibit A-1 (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-2 for mercury load allocation.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times receiving water flow in Indian lands (1,171 MGD at discharge point; 24,333 downstream) times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Brownville
The Town of Brownville (NPDES permit ME0102784) provides wastewater treatment to residential and commercial users, and has no industrial users. The facility discharges wastewater primarily to groundwater via 11 subsurface septic tanks and wastewater disposal systems. The permit authorizes minor discharges from an underdrain to Pleasant River, which is a Class B water. 
DMRs submitted by the facility during the period of 2008 through 2011 indicated that the average quarterly discharge to Pleasant River is 2.6 million gallons. According to the 2012 permit fact sheet, "The Department has made the determination that monitoring the flow from the underdrain is of little value and not necessary to determine compliance with WQS. Therefore, the flow monitoring requirement is being removed from this permit" (p. 5).
Since the facility has no flow limitations, effluent limitations, or monitoring requirements, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Calais POTW
The Calais POTW (NPDES permit ME0100129) serves approximately 3,500 people. The facility has a monthly average flow limitation of 1.5 MGD and an average flow (March 2006 through March 2011) of 0.6 MGD. It discharges treated wastewater to the St. Croix River, which at the point of discharge is classified as a Class SC marine water and outlets to Passamaquoddy Bay. The facility also discharges an unspecified quantity of excess combined sanitary and storm water receiving primary treatment only (and seasonal disinfection) and an unspecified quantity of untreated combined sanitary and stormwater from five combined sewer overflow (CSO) outfalls to the St. Croix River. Four of the CSO outfalls discharge to tidal waters (Class SC) and one discharges to freshwater (Class C).
The permit fact sheet reports that the facility employs a primary and secondary treatment process which includes a headworks section with influent bar screen, a Parshall flume structure for flow measurement, a grit removal system, primary sediment clarifiers, and gravity sludge thickener. After primary clarification, wastewater flows to the secondary biological treatment which includes reactors, mechanical surface aerators, and settling clarifiers.
Effluent Data 
Exhibit A-4 summarizes the last five years of effluent monitoring data for priority pollutants for which data are available and at least one observation was above the detection level. 
Exhibit A-4. Summary of Effluent Data: Calais POTW
Pollutant[1]
Total Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Cyanide
                                       2
                                      2.0
                                      2.0
                                      1.5
Dichlorobromomethane
                                       1
                                       
                                      1.6
                                      1.6
Mercury
                                       9
                                       
                                     0.022
                                    0.0103
Toluene
                                       1
                                       
                                      26
                                      26
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
This facility discharges to the St. Croix River, downstream of the Baileyville POTW and Woodland Pulp facilities. Downstream of Calais, the river enters Passamaquoddy Bay at Pleasant Point. As noted in Section A.1.2, Baileyville POTW and Woodland Pulp both have detected mercury concentrations in their effluent, as does the Calais POTW. EPA conducted the reasonable potential analysis considering the cumulative impact of the three dischargers at the point where the flow enters waters in Indian lands. Exhibit A-2 shows the mercury allocation among the three dischargers.
At the point where the facility's flow reaches waters in Indian lands (Passamaquoddy Bay at Pleasant Point), EPA estimated that the flow is 24,333 MGD (see Appendix C). EPA calculated the receiving water's assimilative capacity from the facility at that point based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-5, the facility does not have reasonable potential to exceed the proposed or baseline criteria.
Exhibit A-5. Reasonable Potential Analysis for Calais POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Cyanide
                                                                            3.8
                                                                         0.0951
                                                                           100%
                                                                             NA
                                                                             NA
Dichlorobromomethane
                                                                            6.2
                                                                         0.1241
                                                                           100%
                                                                       365.2870
                                                                      1698.5845
Mercury
                                                                            1.8
                                                                         0.0005
                                                                          19.8%
                                                                         0.0195
                                                                             NA
Selenium
                                                                            6.2
                                                                         0.8532
                                                                           100%
                                                                     10593.3229
                                                                             NA
Toluene
                                                                            6.2
                                                                         2.0166
                                                                           100%
                                                                      7123.0964
                                                                   1479412.3338
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration from Exhibit A-4 (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-2 for load allocations.
4. Based on the applicable marine criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times receiving water flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Calais School
The Calais School Department (NPDES permit ME0102765) provides wastewater treatment to 356 students and 42 staff. The school is authorized to discharge a flow of up to 13,000 GPD and has an average flow (January 2008 through December 2011) of 4,446 GPD. Discharge is to the St. Croix River, which is classified as a Class SC marine water at the point of discharge. The treatment process consists of primary treatment from a septic tank and secondary treatment from a sand filter bed with chlorine disinfection. 
The school has a chronic dilution factor of 38,000 based on a permitted flow of 13,000 GPD; prior testing showed that toxic compounds are not present in the effluent. As such, this facility is exempt from priority pollutant scan requirements under 06-096 CMR 530(2)(A). For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Cobb State Fish Hatchery
The Cobb State Fish Hatchery (NPDES permit 0001104) is operated by the Maine Department of Inland Fisheries and Wildlife (MDIFW). It discharges wastewater associated with hatching and rearing facilities to Cold Stream, a Class A tributary to Passadumkeag River, and has a monthly average flow limitation of 5.0 MGD. The hatchery does not have any limits on human health related pollutants, or any priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this discharger to exceed the proposed criteria, and that it will not have any costs.
Covanta Maine 
Covanta Maine (NPDES permit ME0023213) is a base-loaded biomass energy production facility that burns wood chips as fuel, generating approximately 24.5 megawatts of electricity daily. Wastewaters produced include cooling tower blowdown, building and equipment drain water, and minor quantities of stormwater. These wastewaters are collected and discharged to the Penobscot River, a Class B water. Before discharge, the drain water and some stormwater are treated via an oil/water separator.
Exhibit A-6 summarizes the flow data for outfalls at the facility. Collectively, the facility is limited to discharge 187,000 GPD. The facility does not have any limits on human health related pollutants, or any priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not incur incremental costs.
Exhibit A-6. Outfall Data for Covanta Maine Facility[1]
Outfall
Wastewater Characterization
Maximum Allowable Flow (gallons per day)
Average Flow (gallons per day)
Outfall #001
Cooling tower blowdown waters
                                                                        150,000
                                                                         17,553
Outfall #002
Low-volume drain waters
                                                                          1,000
                                                                            765
Outfall #003
Sand filter backwash
                                                                         36,000
                                                                         18,926
Outfalls #004 through #008
Storm water runoff
Stormwater pollution prevention plan and visual inspections of discharge

Dolby Hydro Project
The Dolby Hydro Project (NPDES permit ME0036528) is a hydroelectric generating facility owned by Great Lakes Hydro America. It discharges non-contact cooling water to the Penobscot River, a Class C water. The facility's flow rate is variable, with a daily maximum of approximately 364,320 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 4). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Dover-Foxcroft Water District
The Dover-Foxcroft Water District (NPDES permit ME0102229) is a drinking water treatment plant serving approximately 2,400 customers. It withdraws an average of 0.3 MGD of water (0.8 MGD maximum) from Salmon Stream Pond. Effluent is discharged after water treatment and clarification process to the Piscataquis River, a Class B water. The monthly average flow limitation for the facility is 0.15 MGD and the average (October 2009 through October 2012) is 0.1 MGD. Due to the nature of the wastewater (filter backwash), the facility does not have any limits on human health related pollutants, nor any priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not incur any incremental costs.
Dover-Foxcroft WWTP
The Dover-Foxcroft WWTP (NPDES permit ME0100501) serves approximately 3,100 people. The facility has a monthly average flow limitation of 0.8 MGD and an average flow (January 2011 through June 2014) of 0.29 MGD. It discharges treated wastewater to the Piscataquis River, which is classified as a Class B water. The permit fact sheet reports that the facility employs secondary treatment consisting of aeration lagoons.
Effluent Data 
Exhibit A-7 summarizes the last five years of effluent data for the treated wastewater for the pollutants of concern for which data are available and at least one observation was above the detection level, based on priority pollutant monitoring data. 
Exhibit A-7. Summary of Effluent Data: Dover-Foxcroft WWTP
Pollutant[1]
Number of Observations
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Mercury
                                       9
                                       
                                     0.006
                                    0.0024
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
This facility, as well as the Guilford-Sangerville WWTF, the Milo POTW, and the Dover-Foxcroft Water District facility all discharge to the Piscataquis River upstream of waters in Indian lands. Of the four facilities, three (Dover-Foxcroft WWTP, Guilford-Sangerville WWTF, and Milo POTW) have detected mercury in their effluent. Additionally, at the point where the facilities' flow enters waters in Indian lands, at the confluence with the Penobscot River, it mixes with discharges from facilities on the Penobscot River above the confluence. As such, EPA conducted the reasonable potential analysis considering the cumulative impact of all dischargers at the point where the Piscataquis River enters waters in Indian lands at the confluence with the Penobscot River. Exhibit A-8 summarizes the load allocation at that point.
Exhibit A-8. Mercury Load Allocation for Penobscot River (Piscataquis Confluence)
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Howland POTW
                                                                            0.3
                                                                        0.00240
                                                                        0.00001
                                                                           3.2%
Lincoln Sanitary District
                                                                           1.07
                                                                        0.00230
                                                                        0.00002
                                                                          10.9%
Millinocket POTW
                                                                           2.33
                                                                        0.00625
                                                                        0.00012
                                                                          64.6%
Guilford-Sangerville
                                                                           0.93
                                                                        0.00210
                                                                        0.00002
                                                                           8.7%
Milo POTW
                                                                           0.39
                                                                        0.00238
                                                                        0.00001
                                                                           4.1%
Dover-Foxcroft
                                                                            0.8
                                                                        0.00244
                                                                        0.00002
                                                                           8.5%
Total
                                                                              
                                                                              
                                                                        0.00019
                                                                         100.0%
1. Based on permit fact sheets for all facilities. For Guilford-Sangerville, the highest permitted flow.
2. Based on priority pollutant scan data for the last 5 years or data from permit fact sheets.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

Additionally, after it meets the Penobscot River, discharge from these facilities mixes with discharges from other facilities on the Penobscot River further downstream. The most downstream of these facilities is the Penobscot Indian Nation facility. As such, EPA also calculated the mercury allocation among all facilities on the Penobscot River (and the Piscataquis River tributary), as shown in Exhibit A-9.
 Exhibit A-9. Mercury Load Allocation for Penobscot River, Downstream
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Howland POTW
                                                                            0.3
                                                                         0.0024
                                                                       0.000006
                                                                           3.1%
Lincoln Sanitary District
                                                                           1.07
                                                                         0.0023
                                                                       0.000021
                                                                          10.7%
Millinocket POTW
                                                                           2.33
                                                                         0.0063
                                                                       0.000121
                                                                          63.4%
Penobscot Indian Nation
                                                                            0.1
                                                                         0.0044
                                                                       0.000004
                                                                           1.9%
Guilford-Sangerville
                                                                           0.93
                                                                         0.0021
                                                                       0.000016
                                                                           8.5%
Milo POTW
                                                                           0.39
                                                                         0.0024
                                                                       0.000008
                                                                           4.0%
Dover-Foxcroft
                                                                            0.8
                                                                         0.0024
                                                                       0.000016
                                                                           8.4%
Total
                                                                              
                                                                              
                                                                      0.0001917
                                                                         100.0%
1. Based on permit fact sheets for all facilities. For Guilford-Sangerville, the highest permitted flow.
2. Based on priority pollutant scan data for the last 5 years or data from permit fact sheets.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

At the confluence of the Piscataquis River and the Penobscot River, where the facility's flow reaches waters in Indian lands, EPA estimated the harmonic mean flow to be 5,328 MGD (based on USGS stream gage data; see Appendix C). At the most downstream point, where the Penobscot Indian Nation discharges, the harmonic mean flow is 5,374 MGD. EPA calculated the river's assimilative mercury capacity from the facility at both points based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-10, the facility does not have reasonable potential for mercury under either criteria.
Exhibit A-10. Reasonable Potential Analysis for Dover-Foxcroft WWTP
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury, confluence
                                                                            1.8
                                                                        0.00007
                                                                           8.5%
                                                                        0.00184
                                                                             NA
Mercury, downstream
                                                                            1.8
                                                                        0.00007
                                                                           8.4%
                                                                        0.00182
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration from Exhibit A-7 (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-8 and Exhibit A-9 for mercury load allocations.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands (5,328 MGD at the confluence; 5,374 MGD downstream) times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

East Millinocket Hydro Project
The East Millinocket Hydro Project (NPDES permit ME0036511) is a hydroelectric generating facility owned by Great Lakes Hydro America. It discharges non-contact cooling water to the West Branch of the Penobscot River, a Class C water. The facility's flow rate is variable, with a daily maximum of approximately 30,240 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 4). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
East Millinocket POTW
The Town of East Millinocket (NPDES permit ME0000175) took over sanitary wastewater treatment at the site of the previous Katahdin Paper Company. The facility also treats landfill leachate from the Dolby landfill as well as stormwater runoff from surrounding areas. The facility discharges to the West Branch of the Penobscot River, a Class C water. The 2015 permit establishes a monthly average flow limitation of 2.0 MGD, and a harmonic mean dilution factor of 775. The facility was first permitted in October 2015, with monitoring requirements established at that time. As such, monitoring data are not yet available, and EPA did not conduct a reasonable potential analysis for this facility, nor identify any effluent limits or costs.
Eustis Hydro Project
The Eustis Hydro Project (NPDES permit ME0036625) is a hydroelectric generating facility owned by KEI (Maine) Power Management (I). It discharges non-contact cooling water to the North Branch Dead River, a Class A water. The facility's flow rate is variable, with a daily maximum of approximately 7,200 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 5). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Grand Lake Stream Fish Hatchery
The Grand Lake Stream Fish Hatchery (NPDES permit 0001082) is operated by the MDIFW. It discharges wastewater associated with filtration, hatchery, and rearing facilities to Grand Lake Stream, and has a monthly average flow limitation of 2.9 MGD. Due to the nature of its discharge, the hatchery does not have any limits on human health related pollutants, or any priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this discharger to exceed the proposed criteria, and that it will not have any costs.
Guilford-Sangerville WWTF
The Guilford-Sangerville WWTF (NPDES permit ME0102032) serves approximately 1,200 residential and commercial users and an average flow (January 2012 to January 2015) of 0.284 MGD. It discharges treated wastewater to the Piscataquis River, a Class B freshwater. The permit fact sheet reports that the facility employs secondary treatment consisting of aeration lagoons. 
The facility has one industrial user, True Textiles, which is a polyester/woolen products manufacturer that contributes approximately 73 percent of inflows to the WWTF. Discharge limitations for the Guilford-Sangerville WWTF are based on discharge flows and production regimes at True Textiles, as summarized in Exhibit A-11. 
Exhibit A-11. Summary of Flow and Limitation Tiers: Guilford-Sangerville WWTF[1]

Tier I
Tier II
A
Subpart G production <42,000 lb/day
Monthly average dry weather flow <=0.465 MGD
Subpart G production >=42,000 lb/day
Monthly average dry weather flow <=0.465 MGD
B
Subpart G production <42,000 lb/day
Monthly average dry weather flow >0.465 MGD
Subpart G production >=42,000 lb/day
Monthly average dry weather flow >0.465 MGD
1. Source: based on 2015 permit fact sheet; "Subpart G" refers to stock and yarn finishing.

Under Tier IA and IIA, the WWTF has a monthly average flow limitation of 0.465 MGD and a dilution factor of 189. Under Tier IB and IIB, the WWTF has a monthly average flow limitation of 0.93 MGD and a dilution factor of 94. The permit fact sheet notes that the facility operated under the Tier IA criteria during the full term of the 2004 permit (2004 to 2010). However, flow monitoring data for 2012 to 2015 indicates that the monthly average flow may have exceeded "A" Tier limitations at some points, with the maximum monthly average flow being 0.536 MGD (2015 permit fact sheet). As such, EPA assumes that the WWTF operates under "B" Tier limitations at least part of the time.
Effluent Data 
Exhibit A-12 summarizes the last five years of effluent data for the treated wastewater for the pollutants of concern for which data are available and at least one observation was above the detection level, based on priority pollutant monitoring data. 
Exhibit A-12. Summary of Effluent Data: Guilford-Sangerville WWTF
Pollutant[1]
Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Antimony
                                       3
                                       
                                      323
                                   226.3333
Mercury
                                      10
                                       
                                     0.004
                                    0.0021
Phenol
                                       6
                                      4.7
                                      5.1
                                    3.8917
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
As described in Section A.9.2, Guilford-Sangerville WWTF, Dover-Foxcroft WWTP, and Milo POTW all discharge to the Piscataquis River upstream of waters in Indian lands, and all three have detected mercury concentrations in their effluent. Exhibit A-8 shows the mercury load allocation for facilities at the confluence of the Piscataquis and Penobscot Rivers, and Exhibit A-9 shows the allocation for all facilities discharging to the Penobscot River at the most downstream point. Guilford-Sangerville WWTF is the only facility with detected concentrations of the other pollutants shown in Exhibit A-12; as such, EPA allocated 100 percent of the assimilative capacity of those pollutants to the Guilford-Sangerville WWTF for this analysis. 
At the confluence of the Piscataquis River and the Penobscot River, where Guilford-Sangerville WWTF's flow reaches waters in Indian lands, EPA estimated the river's harmonic mean flow at 5,328 MGD (based on USGS stream gage data; see Appendix C). EPA calculated the river's assimilative capacity from the facility at that point for each pollutant based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential.
EPA calculated Guilford-Sangerville WWTF's RWC based on its B Tier flow limitation, 0.93 MGD. As shown in Exhibit A-13, the facility does not have reasonable potential to exceed any baseline or proposed criteria.
Exhibit A-13. Reasonable Potential Analysis for Guilford-Sangerville WWTF
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Confluence with Penobscot River
Antimony
                                                                            3.0
                                                                        7.51576
                                                                           100%
                                                                      191.96145
                                                                      219.95582
Mercury
                                                                            1.5
                                                                        0.00005
                                                                           8.7%
                                                                        0.00187
                                                                             NA
Phenol
                                                                            2.1
                                                                        0.08307
                                                                           100%
                                                                   119975.90400
                                                                   420475.55155
Downstream
Mercury
                                                                            1.5
                                                                        0.00005
                                                                           8.5%
                                                                        0.00185
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-8 and Exhibit A-9 for mercury load allocations.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Houlton Water Company POTW
The Houlton Water Company POTW (NPDES permit ME0101290) serves approximately 6,500 people. The facility has a monthly average flow limitation of 1.5 MGD, discharging treated wastewater to the Meduxnekeag River, which is classified as a Class B freshwater. The 2011 permit fact sheet reports that the facility employs secondary treatment consisting of an extended air activated sludge process.
Effluent Data 
Exhibit A-14 summarizes the last five years of effluent monitoring data for priority pollutants for which data are available and at least one observation was above the detection level. 
Exhibit A-14. Summary of Effluent Data: Houlton POTW
Pollutant[1]
Total Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Mercury
                                       8
                                       
                                    0.0030
                                    0.0014
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
This facility and Tate and Lyle Ingredients both discharge to the Meduxnekeag River upstream of waters in Indian lands. Both facilities have detected mercury in their effluent. As such, EPA conducted the reasonable potential analysis considering the cumulative impact of both dischargers at the point where the river enters waters in Indian lands. Exhibit A-15 summarizes the load allocation between the facilities based on permitted flows and average effluent concentrations.
Exhibit A-15. Mercury Load Allocation for Meduxnekeag River
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Houlton POTW
                                                                           1.50
                                                                         0.0014
                                                                       0.000017
                                                                          82.7%
Tate and Lyle Ingredients
                                                                           0.12
                                                                         0.0036
                                                                       0.000004
                                                                          17.3%
Total
                                                                              
                                                                              
                                                                       0.000021
                                                                         100.0%
1. Based on permit fact sheets; for Tate and Lyle Ingredients, the highest permitted flow.
2. See Exhibit A-14 for Houlton POTW and Exhibit A-29 for Tate and Lyle Ingredients.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

At the point where the facility's flow reaches waters in Indian lands, EPA estimated the river's harmonic mean flow of 101 MGD (based on USGS stream gage data; see Appendix C). EPA calculated the river's assimilative capacity from the facility at that point based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-16, the facility does not have reasonable potential to exceed mercury criteria.
Exhibit A-16. Reasonable Potential Analysis for Houlton POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury
                                                                            1.9
                                                                        0.00007
                                                                          82.7%
                                                                        0.00034
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration from Exhibit A-14 (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-15 for load allocations.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Howland Hydro
The Howland Hydro Project (NPDES permit ME0036633) is a hydroelectric generating facility owned by the Penobscot River Restoration Trust. It discharges non-contact cooling water to the Piscataquis River, a Class B water. The facility's flow rate is variable, with a daily maximum of approximately 1,440 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 5). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs. 
Howland POTW
The Town of Howland POTW (NPDES permit ME0101788) treats wastewater from 650 residential and commercial customers (with a population of approximately 1,500 people). The facility is authorized to discharge a monthly average flow of 0.30 million gallons per day (MGD), with an actual average (January 2007 through January 2010) of 0.152 MGD. Discharge is to the Penobscot River (Class B). The facility's treatment process is comprised of two primary and two secondary facultative lagoons operated in series. 
The facility has a chronic dilution factor of 2,997, a permitted flow of 0.30 MGD, and no evidence of toxic compounds present. As such, this facility is categorized as Level IV and does not have priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Effluent Data
The facility has an interim mercury monthly average effluent concentration limit of 12.1 ng/L, and a monitoring frequency of two tests per year. Exhibit A-17 summarizes the available effluent data.
Exhibit A-17. Summary of Effluent Data: Howland POTW
Pollutant
Number of Observations[1]
DL (ug/L)[2]
Effluent Concentrations (ug/L)[3]

Maximum
Average
Mercury
                                      11
                                       
                                    0.0037
                                    0.0024
Source: 2011 Permit (prior 60 months).
1. Number of observations includes results above and below detection levels.
2. DL = detection level; blanks indicate that no detection level was specified.

Reasonable Potential Analysis
This facility discharges directly to waters in Indian lands on the Penobscot River (above the confluence with the Piscataquis River), which also receives mercury discharges from a number of other facilities, as described in Section A.9.2. As such, EPA conducted the reasonable potential analysis both at the point of discharge, where discharges from Howland mix with those from upstream Penobscot River facilities, and considering the downstream cumulative impact of all dischargers to waters in Indian lands. Exhibit A-18 summarizes the load allocation among the facilities at the point of discharge; Exhibit A-9 summarizes the allocation downstream.
Exhibit A-18. Mercury Load Allocation for Penobscot River at Howland POTW
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Howland POTW
                                                                            0.3
                                                                         0.0024
                                                                       0.000006
                                                                           4.1%
Lincoln Sanitary District
                                                                           1.07
                                                                         0.0023
                                                                       0.000021
                                                                          13.9%
Millinocket POTW
                                                                           2.33
                                                                         0.0063
                                                                       0.000121
                                                                          82.1%
Total
                                                                              
                                                                              
                                                                       0.000148
                                                                         100.0%
1. Based on permit fact sheets.
2. See Exhibit A-17 for Howland POTW, Exhibit A-20 for Lincoln Sanitary District, and Exhibit A-23 for Millinocket POTW.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

At the point of Howland POTW's discharge above the confluence with the Piscataquis River, the Penobscot River has a flow of 4,894 MGD. At the point of the Penobscot Indian Nation facility's discharge (at the most downstream facility), the Penobscot River has a flow of 5,374 MGD. EPA calculated the river's assimilative mercury capacity for this facility at both points based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-19, the facility has no reasonable potential to exceed mercury criteria under any scenario.
Exhibit A-19. Reasonable Potential Analysis for Howland POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury, discharge point
                                                                            1.7
                                                                       0.000016
                                                                           4.1%
                                                                       0.000805
                                                                             NA
Mercury, downstream
                                                                            1.7
                                                                       0.000016
                                                                           3.1%
                                                                       0.000683
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration from Exhibit A-1 (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-9 for downstream allocation; Exhibit A-18 for allocation at the discharge point.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands (4,894 MGD at discharge point; 5,374 MGD downstream) times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Lincoln Sanitary District
The Lincoln Sanitary District (NPDES permit ME0101796) serves approximately 4,200 people. The facility has a monthly average flow limitation of 1.07 MGD and discharges treated wastewater to the Penobscot River, which is classified as a Class B freshwater. The 2011 permit fact sheet reports that the facility employs secondary treatment via aeration and chlorine clarification.
Effluent Data 
Exhibit A-20 summarizes the last five years of effluent monitoring data for priority pollutants for which data are available and at least one observation was above the detection level. 
Exhibit A-20. Summary of Effluent Data: Lincoln Sanitary District
Pollutant[1]
Total Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Cyanide
                                       3
                                       5
                                     10.00
                                     6.03
Mercury
                                      10
                                       
                                    0.0030
                                    0.0023
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
As described in Section A.17, Lincoln Sanitary District and several other facilities discharge to the Penobscot River in Indian lands, with the Millinocket POTW upstream of Lincoln Sanitary District. Exhibit A-21 shows the mercury load allocation between the two facilities at the point of Lincoln Sanitary District's discharge. Exhibit A-9 summarizes the load allocation for mercury at the most downstream point for these facilities. 
Exhibit A-21. Mercury Load Allocation for Penobscot River at Lincoln Sanitary District
Facility
Permitted Flow (MGD)[1]
Avg Effluent Conc. (ug/L)2
Loading (lb/day)[3]
Share of Loading[4]
Lincoln Sanitary District
                                                                           1.07
                                                                         0.0023
                                                                       0.000021
                                                                          14.5%
Millinocket POTW
                                                                           2.33
                                                                         0.0063
                                                                       0.000121
                                                                          85.5%
Total
                                                                              
                                                                              
                                                                       0.000142
                                                                         100.0%
1. Based on permit fact sheets.
2. See Exhibit A-20 for Lincoln Sanitary District and Exhibit A-23 for Millinocket POTW.
3. Permitted flow times average effluent concentration times 0.00834 (conversion from ug/L to lb/gallon).
4. Facility loading divided by total loading.

For the purpose of the reasonable potential analysis, EPA considers the impacts of mercury cumulatively at the point where the facility discharges, and downstream where discharges mix with those of other facilities. This calculation is based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-22, the facility does not have reasonable potential to exceed any criteria.
Exhibit A-22. Reasonable Potential Analysis for Lincoln Sanitary District
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Discharge Point
Cyanide
                                                                            3.0
                                                                        0.26771
                                                                           100%
                                                                      110.19586
                                                                             NA
Mercury
                                                                            1.3
                                                                        0.00003
                                                                          14.5%
                                                                        0.00215
                                                                             NA
Downstream
Mercury
                                                                            1.3
                                                                        0.00003
                                                                          10.7%
                                                                        0.00233
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-21 for mercury allocation at the point of discharge and Exhibit A-9 for downstream mercury load allocation.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands (3,670 MGD at discharge point, 5,328 MGD at the confluence with the Piscataquis River, and 5,374 MGD at the most downstream point) times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Mattaceunk Hydro Project
The Mattaceunk Hydro Project (NPDES permit ME0036552) is a hydroelectric generating facility owned by Great Lakes Hydro. The facility discharges non-contact cooling water and miscellaneous non-process waste water from four separate outfalls to the Penobscot River, a Class C water. The facility has a discharge limit of 144,000 gallons per day. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 4). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Mattawamkeag WWTF
The Mattawamkeag WWTF (NPDES permit ME0102245) discharges wastewater to the Penobscot River. It uses an aerated lagoon system and has a design flow of 0.09 MGD. Given this flow and a harmonic mean dilution factor of 40,782, this facility is categorized as Level IV and does not have priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that it will not have any costs.
Milford
The Town of Milford (NPDES permit ME0102695) collects sanitary wastewaters from residential and commercial users, and conveys them to the Town of Old Town's wastewater treatment facility (WWTF) (NPDES permit ME0100471). During rainfall events, untreated sanitary wastewater combines with stormwater from the Bangor Hydro Electric and discharges overflow to the Penobscot River. The Town is authorized to discharge an unspecified amount of untreated sanitary waste during such events, and is required to monitor the flow and number of overflow events, periodically update the Town's CSO Master Plan, and submit annual reports documenting progress toward eliminating overflow events. 
There are no limits on human health related pollutants, nor any priority pollutant scan requirements associated with this permit. For this analysis, EPA assumes that there is no reasonable potential for this discharger to exceed the proposed criteria, and that it will not have any costs.
Millinocket Hydro
The Millinocket Hydro Project (NPDES permit ME0037371) is a hydroelectric generating facility owned by Great Lakes Hydro America. It discharges non-contact cooling water to the Penobscot River, a Class C water. The facility's flow rate is variable, with a daily maximum of approximately 22,000 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 5). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs. 
Millinocket POTW
The Millinocket POTW (NPDES permit ME0100803) serves approximately 5,200 people. The facility has a monthly average flow limitation of 2.33 MGD and an average flow (June 2003 through November 2008) of 1.34 MGD. It discharges treated wastewater to the Penobscot River, which is classified as a Class B freshwater. The permit fact sheet reports that the facility employs secondary treatment consisting of aeration lagoons.
Effluent Data 
Exhibit A-23 summarizes the last five years of effluent data for the treated wastewater for the pollutants of concern for which data are available and at least one observation was above the detection level, based on priority pollutant monitoring data. 
Exhibit A-23. Summary of Effluent Data: Millinocket POTW
Pollutant[1]
Number of Observations
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Mercury
                                       8
                                       
                                     0.017
                                     0.006
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
The Millinocket POTW discharges to the Penobscot River upstream of waters in Indian lands. At the point where the facility's flow enters Indian lands, EPA estimated the river's harmonic mean flow at 3,053 MGD (based on USGS stream gage data; see Appendix C). Further downstream, discharges from this facility mix with those of other facilities along the Penobscot River, as described in Sections A.9 and A.17. At the most downstream point, the Penobscot Indian Nation facility's discharge point, the flow is 5,374 MGD. Exhibit A-9 shows the mercury allocation among the facilities at this most downstream point.
EPA calculated the river's assimilative capacity from the facility at the point where the receiving waters enter waters in Indian lands, and at this most downstream point on the Penobscot River where the facility's discharge mixes with that of seven other facilities. This calculation is based on the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-24, the facility does not have any reasonable potential to exceed the criteria under any scenario.
Exhibit A-24. Reasonable Potential Analysis for Millinocket POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury
                                                                            1.9
                                                                        0.00005
                                                                         100.0%
                                                                        0.00096
                                                                             NA
Mercury, downstream
                                                                            1.9
                                                                        0.00005
                                                                          63.4%
                                                                        0.00107
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-9.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Milo POTW
The Milo POTW (NPDES permit ME0100439) serves approximately 740 residential and commercial users. The facility has a monthly average flow limitation of 0.39 MGD and an average flow (January 2011 through June 2014) of 0.25 MGD. It discharges treated wastewater to the Piscataquis River, which is classified as a Class B freshwater. The permit fact sheet reports that the facility employs secondary treatment consisting of aeration lagoons.
Effluent Data 
Exhibit A-25 summarizes the last five years of effluent data for the treated wastewater for the pollutants of concern for which data are available and at least one observation was above the detection level, based on priority pollutant monitoring data. 
Exhibit A-25. Summary of Effluent Data: Milo POTW
Pollutant[1]
Number of Observations
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Mercury
                                       8
                                       
                                     0.004
                                     0.002
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
As described in Section A.9.2, Guilford-Sangerville WWTF, Dover-Foxcroft WWTP, and Milo POTW all discharge to the Piscataquis River upstream of waters in Indian lands, and all three facilities have detected mercury concentrations in their effluent. At the point where the facilities' flow enters waters in Indian lands, at the confluence with the Penobscot River, it mixes with discharges from facilities on the Penobscot River above the confluence. Exhibit A-8 shows the mercury load allocation at the confluence of the Piscataquis and Penobscot Rivers, and Exhibit A-9 shows the allocation at the most downstream point. 
At the confluence of the Piscataquis River and the Penobscot River, where the facility's flow reaches waters in Indian lands, EPA estimated the river's harmonic mean flow at 5,328 MGD (based on USGS stream gage data; see Appendix C). At the most downstream point, the Penobscot Indian Nation facility's discharge point, the flow is 5,374 MGD. EPA calculated the river's assimilative capacity from the facility at each point based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-26, the facility does not have any reasonable potential to exceed the criteria under any scenario.
Exhibit A-26. Reasonable Potential Analysis for Milo POTW
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury, confluence
                                                                            1.9
                                                                        0.00002
                                                                           4.1%
                                                                        0.00089
                                                                             NA
Mercury, downstream
                                                                            1.9
                                                                        0.00002
                                                                           4.0%
                                                                        0.00088
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-8 and Exhibit A-9.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Passamaquoddy POTW 
The Passamaquoddy POTW (NPDES permit ME0100773) collects sanitary wastewaters from approximately 1,874 residential and commercial users in the Passamaquoddy Pleasant Point Indian Reservation. It discharges treated wastewater to the Passamaquoddy Bay (Class SB coastal waters), and has a monthly average flow limitation of 0.15 MGD. There are no limits on human health related pollutants, nor any priority pollutant scan requirements associated with this permit. For this analysis, EPA assumes that there is no reasonable potential for this discharger to exceed the proposed criteria, and that it will not have any costs.
Passamaquoddy Water District
The Passamaquoddy Water District (NPDES permit ME0102211) operates a drinking water treatment plan supplying approximately 900 customer connections. It withdraws water from an impoundment in Perry Stream (created by the Perry Station Dam). Effluent is discharged after water treatment and clarification process to the Boyden Stream, a Class B water. The monthly average flow limitation for the facility is 0.045 MGD and the average (January 2012 through March 2015) is 0.029 MGD. Due to the nature of the wastewater (filter backwash), the facility does not have any limits on human health related pollutants, or any priority pollutant scan requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not incur any incremental costs.
Penobscot Indian Nation
The Penobscot Indian Nation Water Pollution Control Facility (NPDES permit ME0101311) collects and treats wastewater for 550 residential and commercial users. There are no significant industrial users. The facility uses secondary treatment via screening, filaments control (in an anoxic selector basin), oxidation, and chlorine disinfection. After treatment, wastewater is discharged to the Penobscot River (Class B).
The facility has a permitted monthly average flow limitation of 0.1 MGD and a chronic dilution factor of 20,227; This facility is categorized as Level IV and does not have WET, analytical chemistry or priority pollutant testing requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Effluent Data
The facility has an interim mercury monthly average effluent concentration limit of 7.2 ng/L, and a monitoring frequency of one test per year. Exhibit A-27 summarizes the available effluent data. 
Exhibit A-27. Summary of Effluent Data: Penobscot Indian Nation
Pollutant
Number of Observations[1]
DL (ug/L)[2]
Effluent Concentrations (ug/L)[3]

Maximum
Average
Mercury
                                       3
                                       
                                    0.00635
                                    0.0044
Source: 2013 Permit Attachment B; for the period 1999 to 2012.
1. Number of observations includes results above and below detection levels.
2. DL = detection level; blanks indicate that no detection level was specified.
3. Nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
As discussed in Section A.17, several facilities with detected mercury effluent concentrations discharge to the Penobscot River in or upstream of waters in Indian lands. The Penobscot Indian Nation is the most downstream facility. Exhibit A-9 summarizes the load allocation for mercury among these facilities. At the point of where the Penobscot Indian Nation facility discharges, the Penobscot River has a flow of 5,374 MGD. EPA calculated the river's assimilative mercury capacity from the facility at its point of discharge based on the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-28, the facility has no reasonable potential to exceed mercury criteria under any scenario.
Exhibit A-28. Reasonable Potential Analysis for Penobscot Indian Nation
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury
                                                                            3.0
                                                                       0.000016
                                                                           1.9%
                                                                       0.000417
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-9 for mercury load allocation.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Tate and Lyle Ingredients
Tate and Lyle Ingredients (NPDES permit ME0002216) chemically modifies, dewaters, and redries tapioca, potato, and corn starches. It discharges treated wastewater to the Meduxnekeag River, a Class B freshwater. The permit fact sheet reports that the facility utilizes primary clarification, sludge dewatering, activated sludge basins, secondary clarification, and dissolved air flotation. 
The facility's flow limitation depends on the flow of the Meduxnekeag River. When the receiving water flow is at or above 15 cfs, then the facility has a monthly average flow limitation of 0.06 MGD. During high flows in the Meduxnekeag River (above 50 cfs), the facility's monthly average flow limitation is 0.12 MGD. 
Effluent Data 
Exhibit A-29 summarizes the last five years of effluent data for the treated wastewater for the pollutants of concern for which data are available and at least one observation was above the detection level, based on priority pollutant monitoring data. 
Exhibit A-29. Summary of Effluent Data: Tate and Lyle
Pollutant[1]
Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Bis(2-ethylhexyl)phthalate
                                       1
                                       
                                      32
                                      32
Cyanide
                                       1
                                       
                                       5
                                       5
Mercury
                                       5
                                       
                                     0.007
                                    0.0036
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
As described in Section A.15.2, this facility and the Houlton POTW both discharge to the Meduxnekeag River upstream of waters in Indian lands, and both have detected mercury concentrations in their effluent. Exhibit A-15 shows the load allocations for the two facilities for mercury based on flow limitations and average effluent concentrations. Tate and Lyle Ingredients is the only Meduxnekeag River discharger with detected concentrations of the other pollutants shown in Exhibit A-29; as such, EPA allocated 100 percent of the assimilative capacity of those pollutants to Tate and Lyle Ingredients for this analysis. 
At the point where the facility's flow reaches waters in Indian lands, EPA estimated that the river's harmonic mean flow to be 101 MGD (based on USGS stream gage data; see Appendix C). EPA calculated the river's assimilative capacity from the facility at that point for each pollutant based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential.
EPA calculated Tate and Lyle Ingredients' RWC based on its high-flow limitation, 0.12 MGD. As shown in Exhibit A-30, the facility has reasonable potential to exceed the proposed bis(2-ethylhexyl) phthalate criteria.
Exhibit A-30. Reasonable Potential Analysis for Tate and Lyle Ingredients
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Bis(2-ethylhexyl) phthalate
                                                                            6.2
                                                                        0.19856
                                                                           100%
                                                                        0.02123
                                                                        0.60648
Cyanide
                                                                            6.2
                                                                        0.03102
                                                                           100%
                                                                        3.03242
                                                                             NA
Mercury
                                                                            2.3
                                                                        0.00002
                                                                          17.3%
                                                                        0.00007
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-15 for mercury load allocations; assumed 100 percent for all other pollutants since Tate and Lyle Ingredients is the only discharger with detected concentrations on the Meduxnekeag River.
4. Based on the applicable criterion (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. "NA" indicates that the aquatic life criterion is more stringent than the human health criterion, so no incremental costs are expected to result from the proposed human health criterion. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Effluent Limitations
Information in Tate and Lyle's permit fact sheet indicates that MEDEP establishes discharge limitations for this facility using an assumption that background concentrations are 10 percent of the applicable criteria. Additionally, 15 percent of the receiving waterbody's assimilative capacity (in lb/day) is reserved (i.e., not allocated to any facility). 
EPA calculated the load allocation based on the receiving water stream flow at the point where it reaches Indian lands downstream of the discharge. Exhibit A-31 shows the calculation of the load allocation based on the assimilative capacity for the Meduxnekeag River, the background concentration and reserve allocation, and the facility share of the loading. 
Exhibit A-31. Load Allocation for Tate and Lyle Ingredients
Pollutant
Stream Assim. Capacity (lb/day)[1]
Facility Share[2]
Facility Allocation (lb/day)[3]
                                       
Proposed
Baseline

Proposed
Baseline
Bis(2-ethylhexyl) phthalate
                                                                        0.02359
                                                                               
                                                                           100%
                                                                        0.01769
                                                                               
1. Applicable criterion (see Section 3), converted from ug/L to pounds per million gallons (multiplying by a conversion factor of 0.00834) times the stream harmonic mean flow.
2. See Exhibit A-15 for mercury load allocations; assumed 100 percent for all other pollutants since Tate and Lyle Ingredients is the only discharger with detected concentrations on the Meduxnekeag River.
3. Calculated as stream assimilative capacity minus background and reserve (10 percent and 15 percent of applicable criteria, respectively) times the facility share.

Exhibit A-32 summarizes the calculated effluent limits for Tate and Lyle Ingredients, based on the facility allocation and the permitted monthly flow, compared with the detection level and the maximum and average effluent concentration. 
Exhibit A-32. Effluent Limitations for Tate and Lyle Ingredients
Pollutant
Average Monthly Effluent Limitation (ug/L)[1]
DL[2]
Effluent Conc. (ug/L)[2]
                                       
Proposed
Baseline

Max
Average
Bis(2-ethylhexyl) phthalate
                                                                       17.67500
                                                                               
                                                                             10
                                                                             32
                                                                             32
DL = detection limit. 
1. Facility load allocation (Exhibit A-31) divided by monthly average flow limitation (0.12 under high flow conditions) converted from pounds per million gallons to ug/L (dividing by a conversion factor of 0.00834).
2. See Exhibit A-29; if all effluent observations were above detection, then the detection level is the lowest of either a) Maine's stated reporting limit or b) the lowest detected level.

Compliance Costs
As shown in Exhibit A-32, limits are not needed for this facility under the baseline scenario. However, under the proposed criteria, EPA calculated bis(2-ethylhexyl)phthalate limitations that are below the facility's maximum effluent concentrations. Therefore, EPA estimated costs for a set of compliance strategies that would be expected to reduce pollutant concentrations below the calculated limitations.
Data are not available identifying the sources of bis(2-ethylhexyl)phthalate at Tate and Lyle Ingredients. However, bis(2-ethylhexyl)phthalate is a plasticizer used in manufacturing plastic packaging. Therefore, wash water from packaging or unpackaging operations is a potential source. A pollution prevention (P2) program that identifies likely sources of bis(2-ethylhexyl)phthalate in the facility's wastewater could provide adequate levels of control through updated source control and best management practices. EPA estimated the cost of a P2 program to be $28,000 per year.
If P2 proves ineffective and the other available compliance strategies (i.e., end-of-pipe treatment) would result in substantial and widespread economic and social impacts, the facility might also apply for a variance for bis(2-ethylhexyl)phthalate. EPA estimated the one-time cost associated with pursuing a variance to be $180,000, with minimal costs associated with subsequent renewal of the variance. 
In an upper bound scenario where other compliance strategies are insufficient to reduce bis(2-ethylhexyl)phthalate to the necessary levels (and a variance is not an option), the facility might need to install end-of-pipe treatment to remove bis(2-ethylhexyl)phthalate. For this scenario, EPA has assumed the use of granular activated carbon (GAC) treatment for bis(2-ethylhexyl)phthalate control. GAC is capable of reliably controlling bis(2-ethylhexyl)phthalate at levels below the calculated effluent limitations. To estimate the cost of GAC treatment, EPA used its work breakdown structure (WBS) cost model for GAC with the input values identified in Exhibit A-33.
Exhibit A-33. Input Parameters Used to Estimate Granular Activated Carbon Treatment Costs for Tate and Lyle Ingredients
                                Input Parameter
                                  Input Value
                             Justification/Source
Contaminant
                                     Other
Bis(2-ethylhexyl)phthalate is not among the contaminants with standard designs built into the model
Design Type
                                   Pressure
A small packaged pressure system is more cost-effective for this design flow
Design Flow (MGD)
                                     0.120
Assumes the treatment system would be designed to treat the facility's maximum flow limitation
Average Flow (MGD)
                                     0.032
The facility's actual average flow
Carbon Life Input Type
                     Calculation from Freundlich Isotherm
Data from Chen and Liew, 2003
1[st] Freundlich Constant (Kf) [(ug/g)(L/ug)[1/n]]
                                     11.3

2[nd] Freundlich Constant (1/n)
                                      1.5

Influent Concentration (mg/L)
                                     0.032
See Exhibit A-32
Breakthrough Concentration (proposed criteria) (mg/L)
                                   0.017675

Contaminant Removal Input Type
                                     EBCT
Typical for a readily adsorbed contaminant like bis(2-ethylhexyl)phthalate
Total Theoretical Empty Bed Contact Time (EBCT) (minutes)
                                      15

Minimum number of contactors in series
                                       1
Series operation unlikely to be necessary for a readily adsorbed contaminant like bis(2-ethylhexyl)phthalate
Bed Depth (feet)
                                      6.7
Selected using model's automatic sizing procedure
Vessel Geometry
                                    Upright

Height (feet)
                                      11

Diameter (feet)
                                       4

Interval Between Backwashes (hours)
                                      48
Conservatively selected a short interval given uncertainties about the relevant characteristics of the facility's wastewater
Discharge Option for Spent Backwash
                                    Recycle
Assumed recycling to avoid impacts on facility's discharge flow or characteristics
Management Option for Spent Carbon
                     Regeneration off-site (non-hazardous)
Typical for a small packaged treatment system
GAC Transfer Method
                                Manual transfer
Mechanical transfer would not be required given small system size and long bed life
Characteristic of Holding Tank Solids
                                 Non-hazardous
Hazardous contaminants are unlikely to accumulate in backwash solids
Number of Booster Pumps
                                       1
Assumes pumping required to account for head loss through contactors
Backwash Pumping
                                   New pumps
Conservatively assumes addition of new equipment to backwash the treatment system
Backwash Storage
                                  New storage

Component Level
                                   High Cost
Consistent with an upper-bound estimate of treatment costs

Based on these inputs and after escalating the model results to 2014 dollars, EPA estimated a GAC treatment cost under the proposed criteria of $54,280 per year assuming a discount rate of 7 percent over 20 years. At a 3 percent discount rate, the costs are $43,096 per year. These estimates are conservative because a detailed study of Tate and Lyle Ingredient's internal process operations could result in a more targeted treatment strategy -- for instance, if only a single internal process flow was the source of the bis(2-ethylhexyl)phthalate, then only the contaminated stream would require treatment.
In summary, to bound the estimated compliance costs for bis(2-ethylhexyl)phthalate, EPA estimated costs for a range of compliance strategies. Exhibit A-34 shows the estimated costs for each of these strategies. 
Exhibit A-34. Range of Compliance Costs for Bis(2-ethylhexyl)phthalate for Tate and Lyle Ingredients

                              Compliance Strategy
                             One-Time Cost ($2014)
                       Ongoing Annual Cost ($2014/year)
                          Annualized Cost[1] ($2014)
                                       
                                       
                                       
                                  3% Discount
                                  7% Discount
Pollution prevention
                                                                            $- 
                                                                       $28,000 
                                                                       $28,000 
                                                                       $28,000 
Pollution prevention plus variance
                                                                      $180,000 
                                                                       $28,000 
                                                                       $40,099 
                                                                       $44,991 
Granular activated carbon treatment 
                                                                       $411,519
                                                                        $15,435
                                                                       $43,096 
                                                                       $54,280 
Lower Bound Compliance Cost 
                                                                       $28,000 
                                                                        $28,000
Upper Bound Compliance Cost 
                                                                        $43,096
                                                                        $54,280
1. One-time costs annualized over 20 years at 3 percent and 7 percent.

Washington County Community College
The Washington County Community College (NPDES permit ME0102831) treats sanitary wastewater from approximately 500 students and 60 faculty and staff employees. Treatment consists of a septic tank, a sand filtration system, and a chlorine disinfection system. The College is permitted to discharge up to 10,500 gallons per day to the St. Croix River (Class SB), with average flow of 3,077 gallons per day.
The College has a chronic dilution factor of 30,692 and a permitted flow of 10,500 gallons per day. This facility is categorized as Level IV and does not have WET, analytical chemistry or priority pollutant testing requirements. For this analysis, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
West Enfield Hydro
The West Enfield Hydro Project (NPDES permit ME0036633) is a hydroelectric generating facility owned by Bangor-Pacific Hydro Associates, with discharges of non-contact cooling water to the Penobscot River (Class B). The facility's flow is variable, with a maximum daily discharge of 403,200 gallons. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 5). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs. 
Woodland Hydro
The Woodland Hydro Project (NPDES permit ME0036668) is a hydroelectric generating facility owned by Woodland Pulp, with discharges of non-contact cooling water and other miscellaneous discharges from 6 separate outfalls to the St. Croix River (Class C). The facility has a discharge limit of 194,000 gallons per day. According to the permit fact sheet for the facility, "the Department has determined that neither effluent limitations nor monitoring requirements are necessary to ensure that applicable water quality standards are met" (p. 4). As such, EPA assumes that there is no reasonable potential for this facility to exceed the proposed criteria, and that this facility will not have any costs.
Woodland Pulp
Woodland Pulp (NPDES permit ME0001872) is a kraft pulp mill. The facility has a monthly average flow limitation of 30 MGD and an average monthly flow (January 2010 through July 2013) of 24.8 MGD. The facility discharges treated wastewater to the St. Croix River, which is classified as a Class C freshwater at the point of discharge. The 2014 permit fact sheet reports that the facility employs treatment via primary clarification, sand filters, and sludge separation.
Effluent Data 
Exhibit A-35 summarizes the last five years of effluent monitoring data for priority pollutants for which data are available and at least one observation was above the detection level. 
Exhibit A-35. Summary of Effluent Data: Woodland Pulp
Pollutant[1]
Total Number of Observations[2]
DL (ug/L)[3]
Effluent Concentrations (ug/L)[4]

Maximum
Average
Mercury
                                                                             18
                                                                               
                                                                          0.004
                                                                          0.002
Source: Priority pollutant scan report for October 2010 through October 2015.
1. Includes only pollutants for which there was at least one detected value (all others were unmonitored or all nondetects).
2. Number of observations includes results above and below detection levels.
3. DL = detection level; blanks indicate that no detection level was specified.
4. For pollutants with some detected values, nondetects were assumed to be half the detection level.

Reasonable Potential Analysis
This facility discharges directly to waters in Indian lands. As such, EPA conducted the reasonable potential analysis for this facility at the point of discharge. Based on effluent concentrations in Exhibit A-35, a receiving water harmonic mean flow of 1,171 MGD, a monthly average flow limit of 30 MGD, and a background concentration equal to 10 percent of the applicable criterion (see 2014 permit fact sheet), there is no reasonable potential to exceed the HHC.
As described in Section A.15.2, this facility and the Baileyville POTW both discharge to the St. Croix River in Indian lands, and both have detected mercury concentrations in their effluent. Exhibit A-2 shows the mercury load allocations for the two facilities based on flow limitations and average effluent concentrations. 
At its point of discharge, where Woodland Pulp's effluent reaches waters in Indian lands, the St. Croix River has a harmonic mean flow of 1,171 MGD. EPA calculated the river's assimilative capacity from the facility at that point for each pollutant based on the flow, the applicable criterion (see Section 3), a background concentration equal to 10 percent of the criterion, and the facility share. If the facility's contribution to the receiving water is higher than the associated assimilative capacity, then there is reasonable potential. As shown in Exhibit A-36, the facility does not have reasonable potential to exceed any criteria.
Exhibit A-36. Reasonable Potential Analysis for Woodland Pulp
Pollutant
Multiplier[1]
RWC (lb/day)[2] 
Share[3]
Assimilative Capacity from Facility (lb/day)[4]
                                       

Proposed
Baseline
Mercury, discharge point
                                                                            1.3
                                                                        0.00130
                                                                          98.1%
                                                                        0.00466
                                                                             NA
Mercury, downstream
                                                                            1.3
                                                                        0.00130
                                                                          78.7%
                                                                        0.07767
                                                                             NA
1. Multiplier from US EPA (1991; Table 3-2) based on number of observations and coefficient of variation.
2. RWC = receiving water contribution. Based on the maximum observed concentration (converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) times the multiplier times facility flow limitation. 
3. See Exhibit A-2 for mercury load allocation.
4. Based on the applicable criterion (freshwater at the point of discharge and marine downstream; converted from ug/L to pounds per million gallons using a conversion factor of 0.00834) minus background concentration (10 percent of criterion) times stream flow in Indian lands times the facility share. "NA" indicates that the aquatic life criterion is more stringent than the human health criterion, so no incremental costs are expected to result from the proposed human health criterion. Bolded red values indicate that the calculated facility RWC is higher than the assimilative capacity from that facility, and there is reasonable potential.

Woodland Pulp: North Site
Woodland Pulp also has a separate permit for its North Site (NPDES permit ME0022063). This permit is for non-contact cooling water and miscellaneous non-process wastewaters discharged to the St. Croix River (Class C). The facility is authorized to discharge up to 15.0 MGD of cooling water (with an average reported discharge of approximately 14 MGD) and 160,000 gallons per day of non-process wastewaters (with an average daily flow of approximately 60,000 gallons). However, the non-process wastewater discharge is not active. Additionally, due to the nature of other discharges (cooling water only), there are no limits on human health related pollutants, nor any priority pollutant scan requirements associated with this permit. For this analysis, EPA assumes that there is no reasonable potential for this discharger to exceed the proposed criteria, and that it will not have any costs. 

Derivation of Mercury Water Column Concentration for Use in Evaluating Reasonable Potential
EPA's proposed criterion for methylmercury is in terms of mg of dissolved methylmercury per kilogram of fish tissue, calculated using the following equation (US EPA, 2001a):
TRC=BWx(RfD-RSC)FI
where:
    TRC		= 	tissue residual concentration in mg methylmercury/kg fish 
    BW	 	= 	human body weight [80 kg]
    RfD	 	= 	reference dose (noncancer human health effects) [0.0001 mg/kg BW-day]
    FI 		= 	human fish consumption rate [0.286 kg fish/day] 
    RSC		= 	relative source contribution [0.000027 mg methylmercury/kg BW-day]
EPA used these assumptions to calculate a total mercury water column concentration equivalent to the methylmercury fish tissue concentration criteria values for use in evaluating reasonable potential for exceedances of the proposed criteria. 
First, EPA calculated a dissolved methylmercury water column concentration based on the following equation (US EPA, 1980):
AWQC = (RfD-RSC) x 1000 x BWDI+(FIxBAF)
where:
    AWQC	= 	ambient water quality criterion in ug/L
    BW	 	= 	human body weight [80 kg]
    RfD	 	= 	reference dose (noncancer human health effects) [0.0001 mg/kg BW-day]
    FI 		= 	human fish consumption rate [0.286 kg fish/day] 
    RSC		= 	relative source contribution [0.000027 mg methylmercury/kg BW-day]
    DI	 		= 	drinking water intake [2.4 L/day]
    BAF 		= 	bioaccumulation factor [2700000 L/kg fish]
This calculation yields dissolved methylmercury criteria in ug/L. To translate these to total mercury water column criteria, EPA divided by 0.014, which is a default national methylmercury to total mercury translator for rivers from US EPA (2010b). For the purpose of the cost analysis described in Section 4, EPA applied a total mercury water column concentration of 0.00054 ug/L for the proposed criterion.
Note that, as discussed in Section 2.2.2, MEDEP established interim mercury effluent limits for each permittee. In accordance with 38 MRS Chapter 520, a facility does not violate the ambient criteria for mercury if the facility is in compliance with its interim discharge limit or with a remediation or corrective action plan, license or order approved either by MEDEP or EPA. EPA does not expect the proposed mercury criteria to affect baseline interim mercury effluent limits.
Estimated Flows for Selected Receiving Waters in Indian Lands
EPA obtained flow statistics for selected receiving waters in Indian lands, downstream from permitted facilities to assess the potential for exceeding proposed criteria for these waters. This appendix provides the relevant data, summarized in Exhibit C- 1.
Exhibit C- 1. Flow Statistics for Selected Receiving Waters in Indian Lands. 
Location
Stream Gage
Harmonic Mean Flow (MGD)[1]
7Q10 
(MGD)
Meduxnekeag River flow at Indian lands
USGS 01018035 Meduxnekeag River at Lowery Rd. nr Houlton, Maine
                                                                            101
                                                                              8
Passamoquoddy Bay flow at Indian lands
Based on DCP analysis (see Section C.2)
                                                                         24,333
                                                                         24,333
Penobscot River flow at upstream boundary for waters in Indian lands
USGS 01030000 Penobscot River Near Mattawamkeag, ME
                                                                          3,053
                                                                          1,555
Penobscot River flow at confluence with Piscataquis River
USGS 01034500 Penobscot River at West Enfield, Maine
                                                                          5,328
                                                                          1,961
1. See Section C.1.

Harmonic Mean Flow
The following equation is used to calculate the harmonic mean flow for any set of flow data:
                                       
where: 
   HM 	= 	harmonic mean flow
   Qi 		= 	nonzero flow
   NT 		= 	total number of flow values
   N0 		= 	number of zero flow values
Dissolved Concentration Potential
NOAA developed dissolved concentration potential (DCP) estimates for East Coast estuaries (NOAA and EPA, 1989) based on the rate and volume of freshwater inflows into the estuary, relative to the total volume of the estuary. The DCP reflects the effect of flushing and estuarine dilution on a load of a conservative, dissolved pollutant to an estuary, assuming average concentration throughout the estuary and steady-state conditions. 
For this analysis, EPA used the DCP for Passamaquoddy Bay to calculate a rough estimate of potential concentrations in the Bay from permitted discharges to the St. Croix River from Calais POTW and Woodland Pulp facilities about 20 and 30 miles upstream, respectively, from Indian lands at Pleasant Point. 
The DCP may be used to calculate the concentration in the Bay, Cbay, as follows:
[1]		CBay=LxDCP10000
Where L is the pollutant load in tons per year, calculated from the permitted flow rate and effluent concentration. 
NOAA/EPA estimated a DCP for Passamaquoddy Bay of 0.27. After replacing the pollutant load L in equation 1 by the product of the effluent concentration and flow rate, adding appropriate unit conversion factors, and rearranging the terms, we get the following ratio between concentration in the effluent and concentration in the Bay, i.e., dilution factor:
[2]		CeffluentCBay=100008.34 xQeffluentx365x0.0005xDCP
Where Qeffluent is the effluent discharge flow limit, in MGD.
The dilution factor is 16,222:1 for the Calais POTW, based on a permitted monthly average discharge flows of 1.5 MGD, and 811:1 for the Woodland Pulp facility, based on permitted monthly average discharge flows of 30 MGD.
Note that this approach to estimating dilution factors differs from that used by MEDEP in cases where a facility discharges directly to estuarine or coastal waters. EPA determined that the use of DCP is appropriate in this case since the discharge does not occur directly in estuarine waters but occurs in the St. Croix river 20 to 30 miles upstream from Passamaquoddy Bay; it can reasonably be assumed to be well-mixed by the time it reaches the Bay.
Review of pH Limitations in Existing Permits and Cost Potential
EPA reviewed the existing permits for facilities that discharge to waters in Indian lands and their tributaries to assess the potential for costs related to the proposed pH criteria. 
Because the treatment of effluent to reduce metals result in altered pH levels in the discharge, EPA focused its evaluation on the six dischargers with permit limitations and detected effluent records for heavy metals and/or arsenic. The sections below summarize EPA's evaluation of the implications of the proposed pH limit of 6.5 on each of the facilities. 
Calais POTW 
The September 29, 2006 permit authorized the monthly average discharge of up to 1.5 MGD of secondary treated sanitary wastewater, an unspecified quantity of excess combined sanitary and storm water receiving primary treatment only (and seasonal disinfection) from a municipal WWTF and an unspecified quantity of untreated combined sanitary and storm water from five (5) combined sewer overflow (CSO) outfalls to the St. Croix River, Class SC, in Calais, Maine.
Evaluation: The facility discharges mostly secondary or primary treated wastewater, with occasional stormwater from five CSO outfalls. The permit makes no mention of significant influx of industrial process water. Accordingly, EPA assessed this facility as unlikely to be affected by the proposed pH criterion. 
Guilford-Sangerville
The June 11, 2010 permit authorizes the discharge of up to a monthly average flow of 0.93 MGD of secondary treated sanitary waste waters to the Piscataquis River, Class B, in Guilford, Maine. The permit mentions that the facility receives wastewater output from one industrial contributor, True Textiles. True Textiles is a manufacturer of polyester/woolen products that at full production capacity, contributes approximately 73 percent of the total flow; 97 percent of the BOD5, 14 percent of TSS; and 92 percent of COD.
True Textiles pre-treats waste waters conveyed to the GSSD WWTF via flow equalization and neutralization utilizing an automated pH control system which adds acid or caustic chemical solutions as needed. The flow is measured using a parshall flume prior to being conveyed to the GSSD treatment facility
GSSD permit effluent limitations and monitoring requirements (ELMR) condition 6 (i), specify the pH range as 6.0 to 9.0 SU pursuant to a Department rule, 06-096 CMR Chapter 525(3)(III)(c) along with a 3/Week monitoring requirement. The limits are considered BPT. 
A review of the DMR data for the period January 2012  --  January 2015 indicates that the permittee met the pH range limits, with pH ranging between a minimum of 6.4 SU and a maximum of 8.6 SU. As a result, MEDEP reduced the monitoring frequency from 3/week to 2/week for Tier 1A (current production level) which is consistent with Department guidance on monitoring frequency reductions.
Evaluation: True Textiles is the source of the metals and other toxics monitored. Based on existing pre-treatment and DMR data, EPA judged this facility unlikely to incur incremental costs due to the proposed pH criterion. 
Houlton WWTF
The February 16, 2005 MEPDES permit authorized the monthly average discharge of up to 1.5 MGD of secondary treated wastewaters from a POTW to the Meduxnekeag River, Class B, in Houlton, Maine. There are no major commercial or industrial users of the system that contribute more than 10 percent of the flow or pollutant loading to the waste water treatment facility.
Permit ELMR Condition 6(g)... summary of pH data as reported on the monthly DMRs for the period of January 2007 through August 2010 (# DMRs = 44) indicates the facility has been incompliance with the pH range limitation 100 percent of the time during said reporting period. 
Evaluation: Effluent is secondary treated wastewater with little influx of industrial process water. EPA judged this facility unlikely to incur incremental costs due to the proposed pH criterion. 
Lincoln Sanitary District 
The permit authorizes the discharge of up to a monthly average flow of 1.07 MGD of secondary treated sanitary waste waters and an unspecified quantity of primary treated combined sanitary and storm water to the Penobscot River, Class C, in Lincoln, Maine. The pH range for the outfall is 6.0-9.0. 
Evaluation: The dilution factor for the receiving water is a minimum of 470:1. A review of the DMR data provided in the permit fact sheet for the period February 2006  -  February 2011 (n=59) indicates the pH range was 6.7 SU  -  7.4 SU. EPA judged this facility unlikely to incur incremental costs due to the proposed pH criterion. 
Tate and Lyle 
The facility utilizes approximately 94,000 GPD of municipal water from the Houlton Water Company for use in its manufacturing processes. The permit authorizes the discharge of: (1) 0.04 million gallons per day (MGD) of boiler blowdown and process waste waters to the Meduxnekeag River, Class B, via Outfall #001; (2) 0.05 MGD of non-contact cooling waters to the Meduxnekeag River, Class B, via Outfall #002; and (3) non-contact cooling waters, boiler blowdown and process waste waters to ground water, Class GW-A, via a surface wastewater disposal system (spray irrigation). The permit established a pH range limitation of 6.0  --  9.0 SU for Outfall 4001A which is considered best practicable treatment (BPT) and is consistent with the effluent guidelines established at 40 CFR Part 407.52.
Evaluation: No compliance history is given. The most stringent dilution factor is 43:1 in the winter. Most of the effluent is boiler blowdown which can have a high TDS content, but shouldn't significantly affect the pH in the receiving water. Based on the relatively small amount of discharge, EPA judged this facility unlikely to incur incremental costs due to the proposed pH criterion.
Woodland Pulp 
The permit authorizes the daily maximum discharge of 40 MGD of treated process waste water, treated sanitary waste waters, treated landfill leachate, treated residuals storage pads leachate and other miscellaneous waste waters associated with the kraft pulp and papermaking process and related operations, and a monthly average discharge of 5.6 MGD of treated storm water runoff and a non-contact cooling waters to St. Croix River. The most stringent dilution factor is 4.6:1.
The permit established a daily maximum pH range limitation of 5.0-9.0 SU, based on technology standards in 40 CFR part 430 (Effluent Guidelines and Standards for the Pulp, Paper, and Paperboard Point Source Category), with a footnote exempting the permittee from violations of the limit if the discharge is within 0.5 SU of the pH of the precipitation or the ambient receiving water pH. 
Evaluation: Within the facility is an "acid sewer" line with flow that must be treated and neutralized. The permit provides no indication of compliance problems with meeting the current pH permit conditions. Historical DMR data included in the fact sheet for Outfall 001 and the period of 2010-2013, shows pH ranging between 6.6 and 8.3 SU, whereas DMR data for the period of 2011-2015 show a range of 5.1 to 8.7 SU. While the facility operations could potentially be affected by the proposed pH criterion (which is more limiting that the existing pH range in effluent limits), the limited information available in the permit fact sheet suggests that the facility may already be able to meet the proposed pH criterion.
Potential Point Source Compliance Costs, 7% Discount Rate
This section summarizes the point source compliance costs using a 7 percent discount rate as an alternative to the main analysis, presented in Section 6.1, which uses a 3 percent discount rate. For more details on the methodology for these analyses, see Section 4.
Exhibit E-1 summarizes EPA's estimates of facility-specific compliance costs and the total costs that may result from the proposed HHC, using a 7 percent discount rate. 
Exhibit E-1. Summary of Estimated Compliance Costs for Proposed Human Health Criteria for Waters in Indian Lands[1]
Facility Name
Pollutant
Estimated Annual Costs
(Thousands; 2014$)[2]
Tate and Lyle Ingredients
bis(2-exylhethyl)phthalate
                                                                      $28 - $54
Total
--
                                                                      $28 - $54
1. See Section 4.1.4 and Appendix A for a description of the methods and assumptions used to develop the facility-specific cost estimates.
2. One-time costs annualized over 20 years using a 7 percent discount rate; see Section 6.1 for costs annualized using a 3 percent discount rate.

Exhibit E-2 summarizes estimates of facility-specific costs and total costs for the proposed bacteria criteria. Note that, since all costs are annual, the results do not depend on the discount rate, and the costs shown in Exhibit E-2 are the same as those shown in Section 6.1. 
Exhibit E-2. Summary of Estimated Compliance Costs for Proposed Criteria for Bacteria[1]
Facility Name
Mean Flow (MGD)
Incremental Annual Cost (thousands; 2014$)[2]

Lower-Bound 
Upper-Bound 
Baileyville
                                                                           0.33
                                                                           $9.0
                                                                          $29.3
Calais POTW
                                                                            0.6
                                                                          $12.6
                                                                          $49.3
Calais School
                                                                       0.004446
                                                                           $0.4
                                                                           $0.7
Dover-Foxcroft WWTF
                                                                           0.29
                                                                           $8.0
                                                                          $25.8
Guilford-Sangerville Sanitary District
                                                                          0.284
                                                                           $7.8
                                                                          $25.2
Houlton POTW
                                                                            1.5
                                                                          $39.9
                                                                         $131.9
Lincoln Sanitary District
                                                                           1.07
                                                                          $22.2
                                                                          $94.2
Millinocket POTW
                                                                           1.34
                                                                          $27.7
                                                                         $117.9
Milo WWTF
                                                                           0.25
                                                                           $6.9
                                                                          $22.2
Passamaquoddy
                                                                           0.15
                                                                           $4.3
                                                                          $13.5
Penobscot Indian Nation WPCF
                                                                          0.057
                                                                           $1.5
                                                                           $5.3
Town of Brownville Subsurface WWTF[3]
                                                                            N/A
                                                                           $0.0
                                                                           $0.0
Washington Comm. College
                                                                       0.003077
                                                                           $0.4
                                                                           $0.5
East Millinocket POTW
                                                                              2
                                                                          $41.2
                                                                         $175.7
Howland WWTF
                                                                          0.152
                                                                           $3.4
                                                                          $13.6
Total
                                                                             --
                                                                         $185.3
                                                                         $705.2
1. See Section 4.2 for a description of methods, assumptions, and uncertainties.
2. No one-time costs are included; costs are calculated directly in annual terms and unaffected by assumptions about the discount rate (i.e., 3 percent or 7 percent).
3. It appears this facility is able to meet its seasonal bacteria limitations without disinfection; accordingly, EPA assumed no additional cost to meet the criteria year-round.

Exhibit E-3 summarizes upper bound estimates of facility-specific and total costs related to the proposed mixing zone policy, annualized using a 7 percent discount rate.
Exhibit E-3. Summary of Upper Bound Estimated of Compliance Costs for Proposed Mixing Zone Policy[1]
Facility Name
Flow Rate (MGD)
Annualized Costs
(thousands; 2014$)[2]
Woodland Pulp
                                                                           15.0
                                                                           $399
Total (Upper Bound)
                                                                             --
                                                                           $399
1. See Section 4.4 for a description of methods, assumptions, and uncertainties.
2. One-time costs annualized over 30 years using a 7 percent discount rate; see Section 6.1 for costs annualized using a 3 percent discount rate.

As summarized in Exhibit E-4, using a 7 percent discount rate to annualize one-time costs, EPA estimated that point source dischargers may incur costs ranging between $213,000 and $1 million as a result of the proposed rule, depending on compliance approaches for meeting potentially more stringent permit conditions. As discussed throughout the report and highlighted in Section 6.3, these costs are subject to significant uncertainty and the estimated range reflects some of this uncertainty. 
Exhibit E-4. Summary of Estimated Point Source Compliance Costs[1]
Proposed WQS
Annualized Costs (thousands; 2014$)[2]
Human health criteria for waters in Indian lands
$28 
                                       
$43.1
Bacteria criteria for waters in Indian lands
$185.3
                                       
$705.2
Mixing zone policy 
Not Estimated
                                       
Up to $273
Total[3]
$213 
                                       
$1,158
1. Excludes costs for proposed ammonia criteria, for which EPA expects costs to be zero. See Section 4.3.
2. Except as otherwise noted (see Section 4.4 for assumptions regarding expected useful life of cooling towers), one-time costs are annualized over 20 years using a 7 percent discount rate. See Section 6.1 for costs annualized using a 3 percent discount rate
3. Lower bound of total costs excludes costs associated with the mixing zone policy for which EPA estimated only the upper bound scenario. See Section 4.4 for details.