## DISCLAIMER

The full text of certain NPDES permits and the asso ciated fact sheets has been made available to provide online access to this public information. EPA is making permits and fact sheets available electronically to provide convenient access for inte rested public parties and as a reference for permit writers. The ownership of these documents lies with the permitting authority, typically a State with an authorized NPDES program.

While EPA makes every effort to ensure that this web site remains current and contains the final version of the active permit, we cannot guarantee it is so. For example, there may be some delay in posting modifications made after a permit is i ssued. Also note that not all active permits are currently available electronically. Only permits and fact sheets for which the full text has been provided to Headquarters by the permitting authority may be made available. Headquarters has requested the full text only for permits as they are issued or reissued, beginning November 1, 2002.

Please contact the appropriate permitting authority (either a State or EPA Regional office) prior to acting on this information to ensure you have th e most up-to-date permit and/or fact sheet. EPA recognizes the official version of a permit or fact sheet to be the version designated as such and appropriately stored by the respective permitting authority.

The documents are gathered from all permitting au thorities, and all documents thus obtained are made available electronically, with no screening for completeness or quality. Thus, availability on the website does not constitute endorsement by EPA.

## E. I. du Pont de Nemours & Company NPDES Permit No. DE 0000051 Chemical & Pigments Department State Permit No. WPCC 3193C/76 104 Hay Road Edge Moor, Delaware 19809

The E. I. du Pont de Nemours & Company Edge Moor (DuPont ) facility has applied for reissuance of its National Pollutant Discharge Elimination System (NPDES) pe rmit No. DE 0000051 issued on September 29, 1989 and amended on March 8, 1990 and October 20, 1993 to dischar ge noncontact cooling water, treated process waste waters, and storm water to the Delaware River and Shellpot Creek.

DNREC published public notice for re issuance of this permit on June 10, 1998. EPA Region III at that time rescinded intake provisions in Delaware’s SWQS, and objec ted to the draft permits inclusion of allowances forpollutants, total suspended solids (TSS) and iron, in the intake from the Delaware River water used in the site’s noncontact cooling water system. The reissued Delaware “Regulations Governing the Control of Water Pollution” 1 

## (RGCWP) include the required provisions addressing pollutants in the intake in § 8.04(d).

This permit expired on September 28, 1994. In accordan ce with State and federal regulations, their NPDES permit renewal application was submitted 3/20/94. That application information is old, and the discussion below reflects that. Where available (e.g., DMR data), more recent data were used in the following permit renewal review. 

# Proposed Changes 2

1. PCBs, dioxins, and furans.

a. Add numeric limits for Outfall 001 for the total of congeners of PCBs, dioxins and furans, as “Toxic Equivalents to 2,3,7,8 TCDD”. b. Require quarterly monitoring for outfall 001 and annual monitoring for Outfall 004.

c. Require maintenance of a ”Pollutant Minimization Plan” (PMP) 3 

## for PCBs, dioxins, and furans for entire site. 2. Outfalls 001, 002, and 003 – Grant request for changes in temperature and flow limits.- In a letter dated August 14, 2006, DuPont requested increases in temperature limit s. The increased temperat ure limits will be offset by decreases in flow limits, such that the total permitted heat discharge (measured as BTU) will be reduced slightly. See Table below for existing and proposed limits:

1

2 

## Effective Date May 14, 2003. Changes are compared to the currently effective permit, not the 6/10/98 Public Notice draft permit. 3 

## From §4.30.0.E.6.C of DRBC’s “Rule For Establishing Pollutant Minimization Plan (PMP) Requirements For Point

And Non-Point Source Dischargers Of Toxic Pollutants Fo llowing Issuance Of A TMDL Or Assimilative Capacity Determination, 4.30.9 Pollutant Minimization Plans for Toxic Pollutants,” adopted May 18, 2005. See http://www.state.nj.us/drbc/PMPrule-May05.pdf

.



# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 2 of 11 Pages

Table 1 -- Proposed Flow and Temperature Limit Changes

Outfall Temperature (°F) Flow (mgd) Change in Heat Discharged (BTU) Current Proposed Current Proposed 001 110 112 5.20 5.20 88 002 110 110 3.00 2.89 -100 003 110 112 6.00 5.90 7 Total 14.2 13.99 -6

3. Outfall 001 – Discharge of treated process wastewater

a. Considering treatment plant performance and RGCWP §7.03(a), i. Reduce the average iron limit from 3.0 to 2.0 mg/L. ii. Delete Special Condition No. 3. It required six months monitoring of Outfall 001 for ammonia, aluminum, copper, silver, mercury, hardness, chlorides, conductivity, and alkalinity. The monitoring has been completed. iii. Grant request (in 3/20/94 renewal appl ication) to reduce chromium monitoring from weekly to monthly. iv. Delete Special Condition No. 4. It required the permittee to “identify valance equilibrium coefficients typical for chromium in discharge 001". That is , identify total vs. hexavalent chromium (chromium +6 

## , the much more toxic form) in the 001 discharge. b. Whole Effluent Toxicity i. Add a compliance schedule to eliminate acute whole effluent toxicity within three years. ii. Acute biomonitoring should remain at quarterly frequency. iii. Add chronic biomonitoring, per the DRBC’s request. iv. Add final limits for acute whole effluent toxicity.

c. Add quarterly monitoring for 1,2 dichloroethane, trichloroethene, Tetrachloroethene, using U.S. EPA test method 601 GC/HAL for purgeable halocarbons, as requested by the Delaware River Basin Commission (DRBC). The DRBC is gathering information regarding loads of these pollutants from multiple potential sources to the Delaware River. 4. Outfalls 002 and 003 - Intake is from the Delaware River. Both discharges are predominantly single-pass noncontact cooling water, with some storm water.

a. For total suspended solids (TSS) and iron, i. Delete current permit’s final limits based on “intake + analytical variability” for iron and TSS. ii. Current monitoring frequency is once per month. Increase frequency to twice per month simultaneous samples on intake, 002, and 003 for TSS and iron. iii. Add a reopener clause into the special conditions that specifically allows reopening the permit to update the iron and TSS limits for 002 and 003, based on analysis of data if needed iv. Require yearly submittal of paired sample results (s ince the permit effective date) in electronic format (Excel, Lotus, etc.).

v. Add Special Condition requiring PMP for iron to iden tify and reduce possible iron sources to the river for outfall 002 and 003. b. Delete Special Condition No. 11. It required controls for storm water runoff from the ilmenite storage pile in the area of Outfall 003. In the future, these contro ls should be included in the Storm Water Plan (SWP). 5. Outfall 004 – Added monitoring requirements for dissolved organic carbon, total organic carbon, and total suspended solids. This monitoring is intended to ev aluate the usefulness of these parameters as surrogate indicators of the presence of PCBs, dioxins, and furans. 6. Require submittal of updated NPDES application Forms 2C and 2F, considering the date of the original permit application (1994). 7. Add Special Condition requiring a storm water plan (SWP) to prevent and minimize contamination of storm water runoff from the site.



# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 3 of 11 Pages 

# Background Information

Activity Description

DuPont Edge Moor manufactures titanium dioxide, ferric chloride, and titanium tetrachloride. 

# Statutory and Regulatory Basis

The Delaware Department of Natural Resources and Environmental Control (DNREC) proposes to reissue an NPDES permit to discharge the wastewater subject to certain effluent discharge limitations, monitoring requirements and other terms and conditions identified in t he draft permit. Section 402 of the federal Clean Water Act, as amended, and 7 Del. C. Chapter 60 provide the authority for permit is suance. Federal and state regulations promulgated pursuant to these statutes are the regulatory bases for permit issuance. 

# Receiving Stream Classification

DuPont Edge Moor’s storm water and non-storm water effl uents discharge to the Delaware River. The Delaware River Basin Commission assesses attainment of desig nated uses for these receiving waters. Zone 5 of the Delaware River does show some nonattainment of designated uses.

Regulatory agencies classify water bodies according to their designated uses (e.g., aquatic life protection, fishing, swimming, etc.). Agencies assess whether each body suppo rts (“attains”) each of its designated uses, and report their assessments in “305(b)” Reports 1 

## (See Table 1, “Use Support in Estuary Assessment Units from 2004 Integrated Assessment”). When a stream is in non-attainment of a designated use, it must be listed on a “303(d) List” (See Table 2, “Final Determination For The State Of Delaware, 2002 Clean Water Act Section 303(d) List Of Waters Needing TMDLs”, for the Delaware Rive r waters), which shows the cause of the impairment, and a schedule for agencies to address thos e impairments, usually via the TMDL 5



## . Table 2 -- 2 Use Support in Estuary Assessment Units from 2004 Integrated Assessment

Parameter Assessment Unit
5A 5B 5C Designated Use Use Support Level Aquatic Life ID Not Supported Not Supported Recreation Supported Supported Supported Drinking Water NA NA NA Fish Consumption Not Supported Not Supported Not Supported Final Assessment Category 3 5 5 5 Notes : NA: Ambient criteria not applied in these zones ID: Insufficient Data Aquatic Life Use Support Assessed by: DO, Temperature, pH, TDS, Alkalinity, Turbidity, Toxicity 4 , Toxic Parameters Recreation Use Support Assessed by: Fecal Coliform Drinking Water Use Assessed by: TDS, Turbidity, Chloride in Zones 2 and 3, Sodium in Zone 3, Toxic Parameters Fish Consumption Use Assessed by : Presence of Advisories. See “ 2004 Delaware River and Bay Integrated List Water Quality Assessment", Tables 3.14 through 3.16, beginning on Pages 57, September 2004, DRBC ( http://www.state.nj.us/drbc/04IntegratedList/EntireReport.pdf ).

1 Called “305(b) Reports” because they are required under Section 305(b) of the Federal Clean Water Act.
2

3 “2004 Delaware River and Bay Integrated List Water Quality Assessment", Table 1.2, Page 4, September 2004, DRBC.

“The water quality standard is not attained. The AU is impair ed or threatened for one or more designated uses by a pollutant( s), and requires a TMDL.” From “2004 Delaware River and Bay Integrated List Water Quality Assessment", §3.3.5, “Method For Assigning Assessment U nits to Integrated List Categories”, Page 47, September 2004, DRBC.
4 The protocol for gathering chronic toxicity data and relat ed information has been questioned. There is a need to collect suppl ementary data in

order to determine the validity of the data used for this listi ng and the extent of the impairment, which may exist in the rive r segment. 5 

## “ TMDL” is the “Total Maximum Daily Load” from point, nonpoint, and natural background sources that a water body can assimilate a nd still

support designated uses. 

# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 4 of 11 Pages

Maps of Assessment Units are available at http://www.state.nj.us/drbc/04I ntegratedList/background2.2.pdf , "Figure 2.3: Main Stem Water Quality Zones for the Delaware River".
Table 3. 2004 Delaware Surface Water Attainment for Shellpot Creek 1

Watershed Segment ID Segment Name Segment Length (miles) or area (acres or sq. miles) Attainment Fish advisory contaminants,

metals or ammonia Min DO Avg DO Bacterial N P Overall

Shellpot Creek DE 300- 001-01 Lower Shellpot Creek 1.0m 1 3 5 5 5 5 PCBs, Chlordane

KEY for Attainment Code 2 1 = Fully Supporting for this parameter 3 = Information is insufficient to make a determination 4a = TMDL has been completed and approved by EPA 4B = Management Actions are ex pected to solve impairment 5 = TMDL Needed



## Table 4 -- 2006 Delaware Fish Consumption Advisories

Waterbody Species Geographical Extent Contaminants of Concern* ** Advice

Delaware River All Finfish Delaware State Line to the C&D Canal PCBs, Dioxin, Mercury, Chlorinated Pesticides No Consumption

Lower Delaware River and Delaware Bay Weakfish-all sizes; Bluefish-14 inches or less Chesapeake & Delaware Canal to the Mouth of the Delaware Bay PCBs No more than one 8­ ounce meal per month

Striped Bass, White Perch, American Eel, Channel Catfish, White Catfish, Bluefish-greater than 14 inches Chesapeake & Delaware Canal to the Mouth of the Delaware Bay PCBs, Mercury No more than one 8­ ounce meal per year***

Shellpot Creek All Finfish Philadelphi a Pike to the De. River PCBs No

From http://www.fw.delaware.gov/Fisheries/AdvisoriesChart.htm


## Notes: * The pollutant listed first is of the greatest concern in this system. ** Proper trimming and cooking of fish can reduce but not eliminate the risk associated with PCBs, dioxins, and chlorinated pesticides. Trimming and cooking does not reduce the risk associated with mercury. *** Women of childbearing age and children should not consume any amount of these fish.

“State of Delaware 2004 Combined Watershed Assessment Report (305(b)) and Determination for the Clean Water Act Section 303(d) List of

Waters Needing TMDLs”, Delaware Department of Natural Resources and Environmental Control, February 25, 2005, Table III-5: (http://www.dnrec.state.de.us/water2000/Sections/Watershed/TMDL/2004%20305_b.pdf, pg 130 of 254 of .pdf file)
2 Ibid. pg 163 of 254 of the .pdf file



# Permit Effective Date: January 1, 2007 1

## DuPont Edge Moor, Fact Sheet Page 5 of 11 Pages

Table 5 -- “Final Determination for The State of Delaware, 2004 Clean Water Act Section 303(d) List Of Waters Needing TMDLs”

SEGMENT (TOTAL SIZE) DESCRIPTION SIZE AFFECTED POLLUTANT(S) AND / OR STRESSOR(S) PROBABLE SOURCE(S) YEAR LISTED TARGET DATE FOR TMDL Pollutant CALM Code Shellpot Creek Lower Shellpot Creek (1.0 mile) From the head of tide below the east set of railroad tracks to the mouth of the Delaware River 1.0 mile Nutrients, DO NPS Delaware

River 1996 2004 (Nutrients, DO and Bacteria) 2009 (PCBs, Chlordane) 5

Bacteria, PCBs,

Chlordane 2002 5

Shellpot Creek Upper Shellpot Creek (14.2 miles) From the headwaters to the head of tide below the east set of railroad tracks 7.7 miles Bacteria, Nutrients, NPS 1996 2004 5

Western tributary of the headwaters to the confluence of the next larger stream order 1.4 miles Biology and Habitat NPS 1998 2009 5

From the headwaters of Matson Run to the confluence with mainstem Shellpot Creek 1.3 miles Biology and Habitat NPS 1998 2009 5

Delaware River DRBC

Zone 5 1 (59.0 sq. mi.) From the PennsylvaniaDelaware line to Liston Point, Delaware. 59.0 sq. mi. Bacteria PS, NPS 1996 2006 (Bacteria) 5

PCBs
PS, NPS, SF 2005 (PCBs) 5 Arsenic, Dioxin, Mercury, Chlorinated Pesticides 2002 2011 (Arsenic, Dioxin, Mercury, Chlorinated Pesticides) 5

Chronic Toxicity PS, NPS, SF 2002 (See Note 1) 3

Iron 2004 (See Note 2) 3 Delaware Bay DRBC Zone 6

(782.0 sq. mi.) From Liston Point to the confluence with the Atlantic Ocean 782.0 sq. mi. PCBs, Bacteria PS, NPS, SF 1996 2005 (for Bacteria) 2006 (for PCBs) 5

Mercury, Dieldrin 2002 2012 5

KEY for Probable Source(s): NPS = Nonpoint Source(s) PS = Point Source(s) SF = Superfund Site(s) KEY for CALM Codes: 1= Fully Supporting for this parameter 3= Information is insufficient to make a determination Note 1. The protocol for gathering chronic toxicity data and related information has been questioned. There is a need to colle ct

supplementary data in order to determine the validity of the dat a used for this listing and the extent of impairment which may exist in the river segment. Note 2. Surface water levels of iron in the segment someti mes exceed the applicable criterion. The Department believes further study of surface water iron levels and a determination of whether a use im pairment is resulting from those levels is an appropriate resp onse to the available information.



# Discharge Description

Ten discharges (Outfalls 001, 002, 003, 004, 005, 006, 007, 008, 009, and 010) are identified in the permit. All of the discharges go directly to the Delaware River except outfall 005 and 010 which discharge to Shellpot Creek then to the Delaware River. Page 2 of the permit lists the constituents of these outfalls:

Outfall 001 - Effluent from the wast ewater treatment system. Outfall 002 - Noncontact cooling water from the fe rric chloride heat exchanger and storm water. Outfall 003 - Noncontact cooling water from Line II (reacti on, purification, oxidation, finishing activities, and hydrocyclone) operations and storm water. Outfall 004 - Storm Water discharge from plant areas to Delaware River Outfall 005 - Storm Water discharge from plant areas to ditch along I 495; the ditch discharges into Shellpot Creek. Outfalls 006, 007, 008, and 009 - Storm Water disc harge from plant areas to Delaware River. Outfall 010 - Storm Water discharge from plant areas to highway catch basin; the catch basin discharges into Shellpot Creek.

1 

## Also see “2004 Delaware River and Bay Integrated List Water Quality Assessment", T able 1.7, Page 8, September 2004, DRBC ( http://www.state.nj.us/drbc/04I ntegratedList/EntireReport.pdf ). 

# Permit Effective Date: January 1, 2007--

-- --

-- --

-- -- -- 

## DuPont Edge Moor, Fact Sheet Page 6 of 11 Pages

The following table summarizes general types of discharge constituents.

Table 6 – Summary of Discharges Constituents

Outfall Flow Limit (mgd) Intake Discharge Components

Process Sanitary Wastewater Noncontact Cooling Water Storm Water

15.9% Public Water 001 5.2 Supply & 84.1% De. Yes -- Yes River Water

002 3.0 De. River Yes Approximately

 2%

003 6.0 De. River Yes Approximately 20% 004, 005, 006, 007, 008, 009, & 010 NA (Storm Water Discharge Only) 100%



## In October 2004, DuPont ceased discharging non-contact cooling water through outfall 002. DuPont has requested keeping Outfall 002 listed as non-contact cooling water based on the current flow basis, to retain an option to send non-contact cooling water through outfall 002 again. The Department agrees to leave Outfall 002 in the permit as requested. Stormwater monitoring requirements will apply to Outfall 002, as long as it consists only of stormwater. DuPont must notify the Department if it will restart nonstormwater discharges via Outfall 002, and the permit’s requirements for nonstormwater discharges via Outfall 002 will become effective.


# Bases for Effluent Limitations

DNREC has examined the application, rece nt discharge monitoring data, and rela ted information. The Department proposes to reissue the facility’s NPDES permit for a period not to exceed five (5) years, subject to the effluent discharge limitations and monitoring requirements shown in the attached permit. The following table outlines the bases for the proposed effluent limitations. Table 7 -- Summary of Bases for Proposed Effluent Limitations and Monitoring

Outfall Parameter Limits or Monitoring Only Water QualityBased 1 Technology-Based

DRBC 2 Effluent Limitation Guidelines PerformanceBased 3 RGCWP 4

001 Flow Limits 9 BOD5 Limits §7.03(a) TSS Limits 40 CFR §415.222 9 Lead Limits 9 Iron Limits 9 §7.03(a) Chromium Limits 40 CFR §415.222 §7.03(a) Nickel Limits 9 40 CFR §415.222
pH 5 Limits 9 40 CFR §415.222 & 40 CFR §401.17 Temperature Limits 9 PCBs Narrative Limits 9 9 Dioxins and Furans Limits 9 Biomonitoring Limits 9 “Free from ...” Limits 9

1

2 

## State of Delaware Surface Water Quality Standards, as amended August 11, 1999. Delaware River Basin Commission 3 

## Performance-based limits are based on t he provisions of 40 CFR 122.45(b)(2)(i).

4 

## “State of Delaware Regulations Governing the Contro l of Water Pollution” (RGCWP), effective May 14, 2003:

§7.03(a), “Effluent Limitations Based on a Practicable Lev el of Pollutant Removal Technology”; and §8.04(d ) “Consideration for Pollutants in Intake Waters When Asse ssing Reasonable Potential”.



# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 7 of 11 Pages

Table 7 -- Summary of Bases for Proposed Effluent Limitations and Monitoring(Continued)

Outfall Parameter Limits or Monitoring Only Water QualityBased 1 Technology-Based

DRBC 2 Effluent Limitation Guidelines PerformanceBased 3 RGCWP 4

002 Flow Limits 9 TSS Monitor 9 §8.04(d) Iron Monitor 9 §8.04(d) pH Limits 9 40 CFR §401.17 Temperature Limits 9 PCBs Narrative Limits 9 Dioxins and Furans 9 “Free from ...” Limits 9

003 Flow Limits 9 TSS Monitor 9 §8.04(d) Iron Monitor 9 §8.04(d) pH Limits 9 40 CFR §401.17 Temperature Limits 9 PCBs Narrative Limits 9 Dioxins and Furans 9 “Free from ...” Limits 9

004 Dissolved Organic Carbon Monitor 9 Total Organic Carbon Monitor 9 Total Suspended Solids Monitor 9 004, 005, 006, 007, 008, 009,

& 010 PCBs Narrative Limits 9 Dioxins and Furans 9

“Free from ...“ Limits 9 ELG’s exist under 40 CFR §415.222 for TSS, Chromium, Nickel, and pH. Stricter criteria exist for TSS, Chromium, and Ni, so the ELG’s are not the bases for the limit numbers, although the existenc e of ELG’s does mean that numeric limits are required.

For Outfalls 001, 002, and 003, the allowable pH range of 6.0 to 9.0 SU. is based on SWQS. 40 CFR §401.17 allows the discharge to be outside the 6.0 to 9.0 S.U. range 1% of the time and is the bas is for the “individual excursion ti me” (I.E.T.) and “total excu rsion time” (T.E.T.) provisions of the pH limit.


# Bases for Effluent Limitations – Discussion

The following provides additional details beyond the m ention under “Proposed Changes” section, beginning on page 1 of this Fact Sheet. 

# PCBs, Dioxins, and Furans

New permit requirements for PCBs, dioxins, and furans (PD& F) affect the entire site. The permit includes a general requirement for a “Pollutant Minimization Plan” to track do wn and eliminate discharges of PD&F. Further, the permit includes numeric limits for PD&F discharge from Outfall 001.

On December 15, 2003 the US EPA Regions II and II adopt ed a Total Maximum Daily Load (TMDL) for PCBs) for Zones 2,3,4, and 5 of the tidal Delaware River. This TMDL requires that facilities identified as discharging PCBs to the Delaware River prepare and implement a Pollutant Minimization Plan (PMP). DRBC has issued guidance documents for completing the PMPs.

Narrative limits for PCBs follow the DRBC’s pollutant minimization plan 5 

## (PMP) requirements for point and nonpoint discharges of toxic pollutants following issuance of a TMDL or assimilative capacity determination. The TMDL for PCBs, “Stage 1 Total Maximum Daily Loads (TMDLs) for polychlorinated biphenyls (PCBs) for Zones 2 through

1

2 

## State of Delaware Surface Water Quality Standards, as amended August 11, 1999. Delaware River Basin Commission 3 

## Performance-based limits are based on t he provisions of 40 CFR 122.45(b)(2)(i).

4 

## “State of Delaware Regulations Governing the Contro l of Water Pollution” (RGCWP), effective May 14, 2003:

§7.03(a), “Effluent Limitations Based on a Practicable Lev el of Pollutant Removal Technology”; and §8.04(d ) “Consideration for Pollutants in Intake Waters When Asse ssing Reasonable Potential”.
5 

## DRBC’s Resolution No. 2005-9 was adopted on May 18, 2005 ( http://www.state.nj.us/drbc/PMP_info.htm ), 

# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 8 of 11 Pages 5 of the Delaware Estuary”, was established on December 15, 2003 by The United States Environmental Protection Agency (EPA) Regions II and III. Promulgation of a TMDL for dioxins and furans is scheduled off 2011. The TMDLs will establish Waste Load Allocations (WLAs) and load allocations for point sources and non-point sources, respectively, and will result in achieving the water quality standards for the waterbody. The Department will reevaluate effluent limitations for this Discharger, to be consistent with WLAs that are derived from new TMDLs.

40 CFR § 122.4(k)(4) allows the use of non-numeric, BMP-ba sed water quality-based effluent limitations where a BMP approach is the most appropriate means to control pollutants to achieve the goals of the Clean Water Act. Minimizing the sources of these PCBs is an effective and e fficient method by which to reduce PCB loading to the Delaware River. A PMP approach that includes sensit ive monitoring, pollutant trackdown, and mitigation of contamination is the most appropriate means to protec t water quality and achieve the goals of the Clean Water Act.

The permit also includes new numeric limits for tota l PCBs, dioxins and furans as “toxic equivalents”, which considers the toxicity of the different congeners of PCBs, dioxins and furans. The PD&F limit is based on the “Human Carcinogens, Fish Ingestion” water quality standard, as promulgated in the July 11, 2004 amendments to the “State of Delaware Surface Water Quality Standards” 1 

## (DeSWQS). Federal NPDES regulations at 40 CFR 122.44(d)(1) specify that water quality based limits must be included in the permit when the regulatory agency determines that a discharge causes, has the reasonable pot ential to cause, or contributes to an excursion above a numeric or narrative water quality criterion within a State water quality standard. Monitoring results from Outfall 001 and DuPont’s landfill waste indicate t hat PCBs, dioxins, and furans are produced in the process and have the potential to generate PCBs, dioxins, and furans in t heir effluent greater than the water quality criteria.

Attachment A shows monitoring results for Outfall 001 monito ring for PD&F, both as total of concentrations of all congeners, and as total of toxic equivalents for all congeners. DuPont has achieved significant reductions of discharges of total PD&Fs, from a high of 879 pg/L 2 

## to the most recent value of 58.1 pg/L (“Sum of Conc’s” on the attachment A graph). DuPont has also managed to reduce Outfall 001 discharge of the more toxic congeners, as measured by total toxic equivalents (“Sum of TEQs” on the attachment A graph).

As for details regarding PD&F requirements, the permit requires the following: 1. Analyze all congeners for PCBs, and so me congeners for dioxins and furans. 2. Use draft Method 1668A for PCBs, per modifications from DRBC 3 

## . Because the method is still “draft”, PCBs will not count towards compliance with the “Toxic Equivalents” limits until the method is finalized and approved under 40 CFR 136, and the permit is modified to include requirements under that method. 3. Use Method 1613b for dioxins and furans. 4. A site-wide Pollutant Minimization Plan (PMP) to track down sources and implement Best Management Practices (BMPs) to reduce pollutant discharges to t he maximum extent practicable for PCBs, dioxins, and furans 5. PMP efforts may rely upon analytical methods other than draft Methods 1668A and 1613b as required above, for purposes of screening or identif ication of pollutant sources.



# Whole Effluent Toxicity

“Whole Effluent Toxicity” measures total toxicity of a wa stewater discharge by exposi ng organisms to the effluent at various dilutions with clean water, then measuring the effe cts. For example, if a sample with 10% effluent and 90% clean water kills all of the test organisms, it is much more toxic than a sample with 90% effluent and 10% clean water with the same effect. “Acute toxicity” tests measur e survival. “Chronic toxicity ” tests will measure additional effects, such as growth and reproduction.

After failing acute biomonitoring tests for Daphnia Magna, the DuPont completed a “Toxicity Identification Evaluation” (TIE) and “Toxicity Reduct ion Evaluation” (TRE), submitting their results to the Department in September, 1993. DuPont’s TIE identified calcium chloride (CaCl) as the cause of acute toxicity. The TRE

1 

## See pages 31 and 32 of the DeSWQS, pages 31 and 32, available at

http://www.dnrec.state.de.us/DNREC2000/Divis ions/Water/WaterQuality/WQStandard.pdf

. 2 

## A picogram (pg) is 0.000000001 milligrams (mg). 3 

## Monitoring, analyses, and reporting shall be according to DRBC requirements at

http://www.state.nj.us/ drbc/PCB_info.htm

. 

# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 9 of 11 Pages
suggested two alternatives to eliminate acute toxicity in the acute mixing zone: source reduction of the CaCl, or install a diffuser to increase dilution in the acute mixing zone. DuPont has elected to install the diffuser, and submitted a “Phase II Diffuser Design Study” Report in September, 2001.

The proposed diffuser will incl ude a multiport design using 3 ports, each wi th a diameter of 6 inches, spaced 7.5 meters apart. Applying the Department’s and the Delawa re River Basin Commission's (DRBC) most restrictive mixing zone criterion of 50 times the discharge length scale re sults in a mixing zone with a radius of 6.8 meters from each diffuser port. This diffuser design would achieve a diluti on ratio of 32.1 to 1 at the edge of this mixing zone at an effluent flow rate of 3.14 MGD.

Utilizing the DRBC’s acute whole effluent toxicity (WET) water quality criterion of 0.3 Toxic Units (acute) or TUa, the resulting wasteload allocation would be 9.6 TUa. Using the recommended permit deriv ation procedures contained in the EPA's Technical Support Document (“TSD”) for Wa ter Quality-Based Toxics Control (U.S. EPA, 1991) and a coefficient of variation (CV) of 0.443 based upon actual effluent data collected from the period 1993 to 2005, the calculated average limit is 5.5 TUa.

The permit includes an average limit of 5.5 TUa for w hole effluent toxicity, requires quarterly sampling for Daphnia magna, and determines compliance with the limit using a 4 quarter running average. The “Schedule of Compliance” under Part I.A.1.a) of this permit provid es three years, starting on the permit effective date, for the permittee to complete reduction of acute toxicity. “Acute Biomonitor ing, Interim Requirements” under Special Condition No. 6 refers to requirements that apply until the sooner of three years after the permit effectiv e date, or the permittee has achieved compliance with the “Schedule of Comp liance”, Part I.C.1.a), “Acute Toxicity”.

DuPont submitted a request for an alternative mixing zone under Section 4.20.5A.1.f. of t he DRBC's Water Quality Regulations by letter dated August 14, 2006. Specifically, DuPont requested a site-specific mixing zone with a 12.1 meter radius around each port, for a d ilution ratio of 40 to 1 at the edge of the acute mixing zone. Using the EPA’s recommended TSD procedures as discussed above, a 40 to 1 dilution ratio results in an average limit of 6.9 TUa. Page 6 of the permit, “Outfall 001 – Final Effluent Limitations And Monitoring Requirements” includes a footnote that provides for the 6.9 TUa average limit to become effectiv e, conditioned upon DRBC appr oval of the site-specific mixing zone.

At the same time, the Delaware River Basin Commission (DRBC) is gathering information to evaluate the combine chronic toxicity effects of multiple wa stewater discharges to the Delaware Ri ver. Toward this end, the permit also requires chronic toxicity testing for Outfall 001.



# Special Conditions

Special Condition No. 1 states that this permit superse des the State Permit WPCC 3193B/76 and NPDES Permit DE 0000051 issued on September 29, 1989, as amended on March 8, 1990 and October 20, 1993.

Special Condition No. 2 is a permit reopener clause.

Special Condition No. 3 states the DRBC's a llocation for oxygen demanding substances.

Special Condition No. 4 requires submitta l of updated NPDES application Forms.

Special Conditions No. 5, 6, and 7 list requirements for test ing and reporting acute whole effluent toxicity for Outfall 001.

Special Condition No. 8 lists requirements for testing and re porting chronic effluent toxicity for Outfall 001. This chronic toxicity monitoring is required per DRBC efforts to assess the possible need for chronic toxicity TMDL for the Delaware River. This Special Condition does not include a Chronic Instream Waste Concentration (IWC c 

## ) that would require Toxicity Reduction Evaluation since appropri ate levels of chronic toxicity reduction would be based upon a DRBC allocation.

Special Condition No. 9 provides for some limited monito ring frequency reductions and testing changes for biomonitoring.


# Permit Effective Date: January 1, 2007

## DuPont Edge Moor, Fact Sheet Page 10 of 11 Pages

Special Condition No. 10 requires a Pollutant Minimization Plan for iron.

Special Condition No. 11 provides details for reporting of analytical results for “Toxic Equivalents” , especially regarding of calculation compliance with the numeric limit for dioxins and furans.

Special Condition No. 12 requires a Pollutant Mi nimization Plan PCBs, dioxins, and furans.

Special Condition No. 13 states monitoring requiremen ts for congeners of PCBs, dioxins, and furans.

Special Condition No. 14 lists monitoring requirements for background levels of iron for Outfalls 001, 002, and 003 at the intake and the discharges.

Special Condition No. 15 lists intake monitoring requirements for background levels of iron for Outfalls 001, 002, and 003 at the intake and the discharges.

Special Conditions No. 16, 17, and 18 list requirements fo r sludges generated in the NPDES wastewater treatment process.
Special Condition No 19 requires the permittee to implem ent and maintain a Storm Water Plan (SWP) to minimize discharge of contaminated st orm water from its facility. 

# Public Notice and Process for Reaching a Final Decision

The public notice of the Department’s receipt of the application and of reaching the tent ative determinations outlined herein will be published in the Wilmington News Journal on ______. Interested persons are invited to submit their written views on the draft permit and the tentative determinations made wi th respect to this NPDES permit application. The Department will not hold a public hearing on this application unless the Department receives a meritorious request to do so or unless the notice of this proposal generates substantial public interest. A public hearing request shall be deemed meritorious if it exhibits a familiarity with the application and a reasoned statement of the permit's probable impact. The request for a public hea ring shall be in writing and s hall state the nature of the issues to be raised at the hearing. All comments received by the close of business on (a date at least 30 days following the date the notice is published) will be consider ed by the Department in preparing the final permit. 

# Department Contact for Additional Information:

Name: John R. DeFriece, P.E. Telephone Number: (302) 739-9946



# Permit Effective Date: January 1, 2007Attachment A – Outfall 001 Congener Monitoring Results(Includes estimated concentrations below the Method Detection Limits for some congeners)Outfall 001, Totals for Detected PCB, Dioxin, & Furan Congeners8799.120.857.9144.6107.029.221.654.358.110.10.0910.0550.005825.150.0110.00290.00220.00540.1900 001000100010 0100100101201230012010123456780 00.00100.01000.10001.000010.0000100.00001,000.000008/31/03 11/30/03 02/29/04 05/30/04 08/30/04 11/29/04 02/28/05 05/30/05 08/30/05 11/29/05 02/28/06 05/30/06Note: Dots on SW QS line (red dashed) indicate dates when samples were taken.

picograms/Liter0123456789 Consecutive Results ≤ SWQSΣConc's (pg/L)ΣTEQs (pg/L)SW QS(pg/L)Conc. LabelsPermit Effective Date: January 1, 2007