Matuszko, Jan 

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Bulleit, Kristy <kbulleit@hunton.com> 

Wednesday, August 05, 2015 2:09 PM 

Southerland, Elizabeth; Wood, Robert; Matuszko, Jan; Jordan, Ronald 

Bulleit, Kristy; Aldridge, Elizabeth; dbhill@southernco.com; Potter, Barbara 

Proposed ELG for Nitrates in FGD waste water 

FGD Nitrates Paper Rev._56471083_5-c.pdf 

As we discussed with you previously, UWAG believes that the proposed limit for nitrates in FGD 

waste water is unnecessary and will pose enormous analytical problems. Attached for your 

consideration is a short paper fw.'ther explaining the bases for our concern. 

Please do not hesitate to contact me or Liz Aldridge (804·788·8549) if you have any questions or 

want to discuss this further. 

Best regards, 

Kr'isty 

Kristy A. N. Bulleit 

Hunton & Williams LLP 

2200 Pennsylvania Avenue, NW 

Washington, DC 20037 

Phone: 

Fax: 

202/955-1547 

202/778-2201 

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• 

1 
Steam Electric Effluent Guidelines: 

Proposed Nitrates Limits for FGD Wastewater Are 

Unnecessary and Will Present Significant Analytical Issues 

• 
I. Introduction 

UW AG requests that EPA refrain from promulgating the proposed nitrate/nitrite limits 

for FGD wastewater. As UWAG explained at its May 4 meeting with EPA, no biological 

treatment can reduce selenium without first reinoving all but trace amounts of nitrate/nitrite in 

FGD wastewater. The same is true for emerging non-biological alternatives for FGD wastewater 

treatment, such as zero valent iron (ZVI) treatment systems under development by several 

vendors. Therefore, imposing a reasonable selenium limit will achieve very substantial 

nitrate/nitrite removal even absent specific nitrate/nitrite limits. 

This paper contains three major points as summarized below. 

I. The existing scientific literature demonstrates that biological treatment of FGD 

wastewater for selenium removal assures removal of all but trace amounts of nitrate/nitrite in 

FGD wastewater. The non-biological treatment systems being developed for possible FGD 

wastewater application also require reduction of nitrate/nitrite before selenium removal can 

occur. 

2. Selenium limits are a proper surrogate for all nitrate/nitrite limits based on the 

clear scientific record and EPA precedent. 

3. The available analytical methods for nitrate/nitrite are unsuited for high-chloride 

matrices like FGD wastewater. The amount of dilution required to manage chloride 

interferences will increase the quantification levels for many samples above the proposed 

regulatory limits. 

II. Biological Treatment Systems Must Remove Nitrate/Nitrite to Reach the Proposed 

Selenium Limits 

EPA has proposed the following selenium and nitrate/nitrite limits for FGD wastewater: 

• 
Table l: EPA's Proposed Selenium and Nitrate/Nitrite Limits 

Parameter Units Daily Maximum Monthly Average 

Selenium f.lg/1 16 10 

Nitrate/Nitrite as N mg/1 0.17 ! 0.13 I 

EPA bases these limits on a combination of physical/chemical and biological treatment. The 

biological treatment portion ofthe system targets selenium removal; but, as a co-benefit of that 

treatment, it also removes all but trace amounts of nitrate/nitrite. [n fact, it is impossible for a 

biological treatment system to remove selenium without first removing nitrate and nitrite, as 

explained below. 

[n biological treatment systems, such as the GE ABMet system, a mixture of naturally 

occurring bacteria are fixed to a bed of granular activated carbon, which acts as a substrate for 

bacterial growth (Sonstegard et al.). Selenium-reducing bacteria use organic carbon (e.g., 

nutrients such as molasses, or specially formulated carbohydrates) as electron donors and 

selenate and selenite as electron acceptors (Envirogen, 20 ll ). However, other parameters in the 

influent stream may inhibit the reduction of selenium: 

Both oxygen and nitrate are more favorable electron acceptors than 

oxidized forms of selenium .... The order use of electron acceptors 

follows the more energetically favorable reactions first .... 

. . . The presence of either oxygen or nitrate will limit selenium 

reduction. Even in anoxic biological systems, the presence of 

nitrates is an important consideration in system design and the 

selection of microorganisms and electron donors .... [H]igh levels 

of nitrate ... will be preferentially reduced before selenium, and 

must be removed before effective selenium reduction will occur. 

Envirogen, 20 II, pp. 4-5. The preferential reduction of oxygen and nitrates over selenium in 

biological treatment systems is well-accepted science. CH2M Hill explains the reduction 

priorities as follows: 

• 

2 
Some denitrifiers [i.e., types of bacteria that can use nitrate as an 

electron acceptor] can use selenate or selenite as an electron 

acceptor but only in the absence of oxygen and nitrate. If either of 

these acceptors is available, selenium will not be reduced 

biologically. To reduce selenium in wastewater, all oxygen and 

nitrate must first be reduced. If a significant amount of nitrate is 

present in the water, then a sufficient amount of organic carbon 

needs to be added to reduce nitrates first, as well as any selenium. 

CH2M Hill, 2010, p. 4-56. Therefore, it is impossible for biological treatment systems to reduce 

selenate and selenite without first removing all but trace amounts of nitrate/nitrite. If either 

oxygen or nitrate/nitrite is available, selenium will not be reduced. The environment within the 

treatment system must be controlled to exclude oxygen, and there must be enough electron 

donors (organic carbon) available to reduce both nitrate/nitrite and selenium in order to treat the 

wastewater for selenium (CH2M Hill, 201 0). 

1. Kinetics Favor Reduction of Nitrate/Nitrite Prior to Selenium 

Reduction 

FGD wastewater entering the treatment system typically has a positive oxidation 

reduction potential (ORP). As the wastewater travels through the bioreactors, the ORP decreases 

due to the reduction of oxidants in the wastewater. As the ORP approaches 0 m V (millivolts), 

denitrification occurs. 

As the ORP drops further into the negative range, selenate and selenite are reduced to elemental 

selenium. 

Seo/- + Organic Carbon ~ Seo/-+ Organic Carbon ~ Se0 + C02 + H20 

Figure I shows common anions and their order of biological reduction based on ORP. 

As shown in this figure, almost all nitrate/nitrite must be removed before any removal of 

selenium occurs. Similar ORP profiles for biological reduction can also be found in Sonstegard 

3 
eta!., pp. 4-5 (Figure 2) for the GE ABMet® system and in Envirogen, 2011 , pp. 4-5 (Figure 2) 

for the fixed-film fluidized bed reactor (FBR) technology. 

Figure 1: The oxidation-reduction potential (ORP) profile from the forced oxidation 

limestone scrubber to the outlet of the bioreactor 

800 

700 

600 

500 

400 

300 

200 

100 

0 

-100 

-200 

-300 

l -400 

Forced oxidation limestone scrubber operation 

(Requires O:\idiling conditions for SO~ rcmo\'al) 

I Denitrification 

I Selenium Reduction 

Sulfate Reduction 

Oxic/Aerobic Conditions 

Anoxic/Anaerobic Conditions 

Figure I also shows that controlling ORP is key to achieving selenium reduction. ORP 

must be in the range of approximately -80 to -250 mVs to achieve selenium reduction. 

Nitrate/nitrite reduction occurs in the range of approximately 20 m V s to -100 m V s, which is 

largely above the level needed for any selenium reduction. Therefore, the biological treatment 

system must move almost all the way through the ORP range for denitrification before any 

significant selenium reduction can occur. 

To achieve significant selenium reduction, the quantity of nutrient provided must be in 

excess of the quantity required to reduce the nitrate/nitrite that is present within the system. 

4 
.. 

Therefore, in biological treatment systems that are designed for selenium reduction, the system 

must preferentially reduce nitrate/nitrite before reducing selenium. 

An emerging technology known as "zero valent iron" treatment technology (ZVJ) also 

requires the reduction or removal of nitrate/nitrite prior to the removal of selenium. ZVI uses 

zero valent iron or elemental iron to reduce selenite and selenate to elemental selenium. There 

are no commercial ZVJ systems currently treating FGD wastewater. However, there have been 

some laboratory and pilot scale evaluations for the process. Although ZVI is not currently an 

available technology for the removal of selenium from FGD wastewater, further research and 

development may make it available in the future. The reduction of selenate and selenite in the 

ZVJ process is a similar mechanism to that of the biological treatment process. The ZVJ acts as 

a reducing agent in the redox reaction. Nitrate/nitrite present in the FGD wastewater competes 

with the selenium for the elemental iron and is chemically reduced to ammonia. Nitrate/nitrite 

therefore greatly increases the amount of treatment chemicals needed in the ZVI system in order 

to attain the selenium reductions that will be required by the proposed ELG. As in the 

bioreactor, the presence of oxygen, nitrate and nitrite will compete with the reduction of 

selenium. CH2MHill 20 l 0, p. 4-45 - 4-48. Therefore, oxygen, nitrate and nitrite must be 

removed first, to ensure adequate treatment for selenium. 

2. Degassing of Biological Treatment Systems is a Necessary Step 

Routine maintenance steps for biological treatment systems ensure proper system 

performance, and thus ensure that both nitrate/nitrite and selenium are removed. Degassing is 

one important and routine step. Nitrogen gas is a byproduct of the nitrate/nitrite reduction 

reactions. The denitrification that occurs within a biological treatment system may impact 

system performance by causing pockets of nitrogen gas to form among the activated carbon beds 

5 
(Sonstegard, 2008). The gas pockets can affect performance by increasing head-loss across the 

bioreactors and impeding flow in the area of the pockets. !d. Biological system manufacturers 

recommend regular degassing of the system and specify steps to achieve the degassing, as well 

as steps to monitor for head-loss that may indicate a need to degas the system. These steps must 

be followed to ensure optimal performance of the system. Any failure to degas as recommended 

by the vendors would lead to exceedances of selenium. Therefore, system operators must degas 

on a routine basis in order to maintain system performance for both nitrate/nitrite and selenium. 

III. Selenium Limits Are an Effective Surrogate for Nitrate/Nitrite 

As EPA acknowledges, not all pol'lutants of concern (POCs) need separate effluent limits 

to ensure adequate pollutant removal. The Technical Development Document for the Proposed 

Effluent Limitations Guidelines for the Steam Electric Point Source Category (TDD) states: 

Effluent monitoring for all POCs is not necessary to ensure that 

steam electric wastewater pollution is adequately controlled 

because many of the pollutants originate from similar sources, 

have similar treatabilities, are removed by similar mechanisms, and 

are treated to similar concentrations. Therefore, it may be 

sufficient to monitor for one pollutant as a surrogate or indicator of 

several others. 

TOO, p. 11-1. For FGD wastewater, EPA explains that ,it "selected arsenic and mercury as 

regulated pollutants and as indicators of effective removals of many other metal pollutants of 

concern present in FGD wastewater, such as cadmium and chromium." TOO, p. 11-2. 

It is common practice to designate indicator or surrogate pollutants. In its 2010 NPDES 

Permit Writers' Manual, EPA states: 

Effluent guidelines are not always established for every pollutant 

present in a point source discharge. In many instances, EPA 

promulgates effluent guidelines for an indicator pollutant. 

Industrial faci)ities that comply with the effluent guidelines for the 

indicator pollutant will also control other pollutants .... 

6 
NPDES Permit Writers' Manual, p. 5-18. In the Landfills ELG, for example, EPA determined 

not to regulate seven pollutants (including chemical oxygen demand and total organic carbon) 

because it found those pollutants were controlled through regulation of other pollutants. 

Development Document for Final Effluent Limitations Guidelines and Standards for the 

Landfills Point Source Category (EPA 2000a), p. 7-9. For the Centralized Waste Treatment 

ELGs, EPA selected indicator pollutants for various groups of pollutants (e.g., tluoranthene as an 

indicator for a group of polyaromatic hydrocarbons; n-decane and n-octadecane as indicators for 

the n-parrafin group). Development Document for the CWT Point Source Category (EPA 

2000b), p. 7-27. 

The situation with selenium and nitrate/nitrite is similar to the above examples. The FGD 

wastewater technology is primarily designed to remove selenium, not nitrate/nitrite. But in order 

to obtain sufficient selenium removal, the system must reduce nitrate/nitrite first. Therefore, it is 

sufficient- and consistent with EPA's policies and past practices- to set limits for selenium 

rather than for both selenium and nitrate/nitrite. 

IV. Nitrate/Nitrite Cannot be Accurately Quantified in FGD Wastewater 

A. Nitrate/Nitrite Methods 

There is another compelling reason for EPA to eliminate the proposed nitrate/nitrite 

limits: the available methods will not produce accurate and reliable results for purposes of 

assessing compliance. There are three primary, approved methods for the analysis of 

nitrate/nitrite in FGD wastewater: EPA Method 353.2, which is a colorimetric method, and EPA 

Methods 300.0 and 300.1, which are ion chromatography methods. As explained below, these 

methods do not produce accurate results in FGD wastewater matrices . 

• 

7 
1. The Proposed Limits are Too Close to the MDL for Method 353.2 

EPA proposed nitrate/nitrite (reported as N) regulatory limits of 0.13 and 0.17 mg/1, for 

the monthly average and daily maximum, respectively. According to the current approved 

version of Method 353.2, the method has an "applicable range" of 0.05 mg/1 to 10 mg/1 in 

drinking, ground, surface, domestic, and industrial wastes. The current unadjusted MDL 

(Method Detection Limit) is 0.05 mg/1, as derived using spiked samples of deionized water. 

The proposed monthly average value for nitrate/nitrite of 0.13 mg/1 is less than three 

times the method's MDL, which is even less than EPA typically uses to set method minimum 

levels (i.e., what EPA considers to be quantitation limits).' If EPA accepts a factor of 3 times the 

MDL as an appropriate quantitation limit, then it is inappropriate for EPA to promulgate a 

compliance limit of 0.13 mg/1, which is less than 3 times the method-specific MDL. And the 

proposed daily maximum of 0.17 mg/1 is barely above 3 times the MDL (0.15 mg/1), and thus 

also inappropriate for determining compliance when measuring within such a complex matrix. 

2. Method 353.2 is Susceptible to Interferences from Chloride a.nd Other 

Constituents in FGD Wastewater 

In addition, FGD wastewater matrices contain much higher levels of chloride than 

drinking, surface, domestic, and typica'l industrial wastes. The presence of chlorides will 

interfere with Method 353.2. Chlorides interfere with the method by limiting reduction 

efficiency. Samples must be diluted to overcome the interference, and sample dilution raises the 

1 In its recent proposed Method Update Rule, EPA defines "minimum level" as follows: 

"The term 'minimum level' refers to either the sample concentration equivalent to the lowest 

calibration point in a method or a multiple of the method detection limit (MDL), whichever is 

higher. Minimum levels may be obtained in several ways: They may be published in a method; 

they may be based on the lowest acceptable calibration point used by a laboratory; or they may 

be calculated by multiplying the MDL ... by a factor of 3. For the purposes ofNPDES 

compliance monitoring, EPA considers the following terms to be synonymous: 'quantitation 

limit,' 'reporting limit,' and 'minimum level."' 80 Fed. Reg. 8956,9027 (Feb. 19, 2015) 

(Method 608.3, Section 23). 

8 
method detection limit and quantitation limit accordingly. Also, the cadmium-copper column 

used to reduce nitrates to nitrites prior to the colorimetric determination can be spent (i.e., used 

up) by other anions that may be present in the matrix, which is another form of interference. In 

summary, this method has limited applicability for FGD wastewaters. If Method 353.2 is used 

for FGD wastewater characterization, site-specific quantification limits must be reported based 

on the dilution factor used to remove the interference. In many cases, the site-specific dilution 

factors will cause the method detection limit and the quantification limit to be above the EPAproposed limits. In these cases, it will be impossible to determine whether the wastewater is in 

compliance with the limits. 

3. Methods 300.0 and 300.1 Are Also Susceptible to Interferences from 

Chloride in FGD Wastewater 

The other primary methods for analysis of nitrate/nitrite are Methods 300.0 and 300.1. 

The methods measure both nitrate and nitrite using an Ion Chromatograph (IC). Ion 

Chromatography works by separating small, soluble ions based on their relative affinities 

between a solid (resin) and a liquid phase. As analytes are carried through a resin-filled column 

by a liquid phase, they are separated with respect to the time required to traverse the column 

because of their differing affinities for the two phases. The analytes are carried through the 

column to a detector that responds to the ions being analyzed. The time required for the peak of 

an analyte to exit the end of the co1lumn is termed the "retention time." The size of the detector 

response is dependent on the amount of the specific analyte present- more analyte gives a larger 

peak. 

A common issue with IC is the interference of two ions that co-elute. The example IC 

scan shown in Figure 2 is published in EPA Method 300.0. The scan shows that the chloride 

(Cl-) (2) and nitrite (N02-) (3) peaks are adjacent to each other. The concentration of Cl- in the 

9 
example chromatogram is 20 mg/1. Cl- concentrations in biologically treated FGD effluent can 

range from 200 to 30,000 mg/1 or even more depending on the recycle rate of the FGD. As 

concentrations ofCI- increase, the chloride peak will overlap the N02- peak, therefore giving 

false positive results for N02-. 

Figure 2: Example IC Chromatograph, Method 300.0 

2 

0 2 

5 

4 

Mlnut 

Method A 

Peak 

1 

2 

3 

4 

5 

6 

7 

7 

6 

Flgtn 1. Chnlmltogram lhCMimg .,.aJan ..ana 1111 AS4A ceum 

(EPA Method 300.0). 

Ret. Time lon mgJL 

1.17 f· 2 

1.73 Ct 20 

2 . .02 NOZ- 2 

u s Br 2 

3.20 NO; 10 

5.38 HPOt 2 

6.92 soz-• 60 

Interferences can be caused by substances with retention times that are similar to the 

anion of interest. Large amounts of an anion, such as chloride (Cl-), can overlap the peak of an 

adjacent anion, such as nitrite (N02-). Sample dilution and/or fortification can be used to solve 

most interference problems associated with retention times. But in the case of FGD wastewater, 

10 
sample dilution to reduce the chloride levels increases the quantification levels above the 

proposed regulatory limits. 

For a pilot FGD wastewater treatment study, a reputable research laboratory was 

employed to measure anions in biologically treated FGD wastewater using Method 300.0. Based 

on data over seven months of operation, the following table shows various chloride levds and 

the sample-specific MDLs achievable for nitrate and nitrite determinations in the biologically 

treated FGD wastewater. The laboratory elected to determine nitrate and nitrite separately to 

minimize the sample dilution effect on the sensitivity of nitrate determination. For nitrite 

determination, a larger sample dilution is required to accurately quantify nitrite levels (by 

reducing the nearby chloride peak). The MDLs and QLs for both nitrite and nitrate are shown in 

Table 2. 

Table 2: Average Nitrate-Nitrite Results in Treated Biological Effluent- Method 300.0 

MDL for Nitrite MDL for Nitrate MDL for Nitrate- Minimum QL 

Chlor,ide, mg/1 as N, mg/1 as N, mg/1 Nitrite as N for NitrateNitrite as N 

I 0,000-15,000 1.25 0.25 1.50 \ 4.50 

5,500-10,000 0.64 0.04 0.68 2.04 

3,000-5,000 0.08 0.36 0.44 1.32 

The results of Method 300.0 show that higher chloride levels result in higher MDLs due 

to the sample dilution needed to reduce the nearby interferences from chloride (next to the nitrite 

peak) and from bromide (next to the nitrate peak). The resulting MDLs for nitrate-nitrite as N 

are I.50 mg/1 for 10,000-15,000 mg/1 chloride, 0.68 mg/1 for I O,OOO-I2,000 mg/1 chloride and 

0.44 for 3,000-5,000 mg/1 chloride. These MDLs are well above the proposed nitrate-nitrite 

limits of O.I3 and 0.17 mg/1. The resulting quantitation limits for these samples are at least three 

times the reported MDLs. Therefore, EPA's proposed nitrate-nitrite limits for FGD wastewater 

are infeasible due to matrix interferences. 

II 
V. EPA's Nitrate/Nitrite Dataset is Limited and Should Not Be Used for Setting Limits 

The EPA subcontractor laboratory selected Method 353.2 to measure nitrate/nitrite in all 

of the FGD wastewater samples collected for EPA's study of the Steam Electric industry. All of 

the data used to derive EPA's proposed nitrate/nitrite limits came from two facilities, Duke's 

Allen and Belews Creek stations. EPA used 16 total daily composite samples of effluent from 

the biological treatment systems for nitrate/nitrate analysis, eight from each treatment plant. At 

each plant, these consisted of four successive days of sampling during one week (labeled "Day" 

samples in Table 3 below), followed by four other samplings of a single sample each, all at least 

two months apart during the course of a year (labeled "Month" samples in Table 3 below). 

EPA's laboratory assigned a reporting tim it (or QL) of 0.1 mg/1 to all of the FGD 

analyses for nitrate/nitrite. Using these data to calculate regulatory limits is problematic because 

12 of the 16 samples analyzed were non-detects (i.e., below the laboratory ML of 0.1 mg/1). 

Table 3: Nitrate/Nitrite Results from Sampling Events Used by EPA to Derive Proposed 

Limits 

SP3 Sample Designation Allen WWTP Nitrate-nitrite BC WWTP Nitrate-nitrite 

nitrogen Results (mg/1) nitrogen Results (mg/1) 

Day 1 <0.1 <0.1 

Day 2 0.13 <0.1 

Day 3 <0.1 <0.1 

Day 4 <0.1 <0.1 

Month 1 <0.1 <0.1 

Month 2 <0.1 0.15 

Month 3 <0.1 0.13 

Month 4 <0.1 0.14 

Of the samples, only four results are quantified, and those values are barely above the laboratory 

ML. All four of the quantified results either equal or exceed the monthly average regulatory 

limit set by EPA. 

12 
Basing regulatory limits on a very small dataset from two plants is not warranted. We 

know that biological treatment systems remove all but trace amounts of nitrate/nitrite before 

removing selenium. Despite this scientific certainty, however, the available data are not 

sufficient for setting nitrate/nitrite limits, particularly limits as low as the ones EPA proposes, 

and particularly in light of inevitable problems with the nitrate/nitrite analytical methods. For all 

these reasons, UWAG requests that EPA refrain from setting nitrate/nitrite limits. 

VI. Chloride Concentrations at Belews Creek and Allen Do Not Reflect All Modes of 

Operation 

As UW AG noted in its 2013 comments on the proposed rule, the chloride concentrations 

for Belews Creek and Allen ranged from 7,000 to 9, I 00 mg/1 and 3,000 to 6,300 mg/1, 

respectively, based on EPA 's data. Some facilities recycle FGD wastewater even more, which 

decreases the amount of scrubber blowdown required and increases the chloride levels in the 

wastewater. In this scenario, chloride levels can range from I 0,000 to 30,000 mg/1 and can be as 

high as 50,000 mg/,J depending on the materials of construction of the scrubber system. These 

high chloride levels will interfere with the ability to measure the remaining small amounts of 

nitrates and nitrites in the treated biological effluent. In fact, the amount of sample dilution 

needed to reduce the chloride concentration will increase the MDL and QL far above the 

proposed nitrate/nitrite limits (more than likely, into the single digit mg/1 range) as indicated in 

Table 2 above. 

VII. Conclusion 

For all of the reasons presented in this paper, EPA should not promulgate the proposed 

nitrate/nitrite limits for FGD wastewater and should instead rely on selenium limits alone as a 

surrogate for nitrate/nitrite removal. 

I. A separate nitrate/nitrite limit is unnecessary, because essentially all of the 

nitrate/nitrite must be removed before selenium can be adequately removed. This 

13 
fact is true for all biological systems as well as for ZVI systems. Therefore, 

selenium Limits will serve as an effective surrogate for nitrate/nitrite limits. 

2. Seventy-five percent of the data used to calculate the limits ( 12 of 16 total 

samples) were below the laboratory-derived quantitation level for the FGD 

wastewater, even though the biological treatment systems at the two facilities 

tested were focused on the removal of selenium. The data therefore support the 

use of selenium limits as surrogates for nitrate/nitrite limits. 

3. For the reasons described in this report, none of the analytical methods can 

consistently analyze nitrate/nitrite in FGD wastewater at extremely low levels 

with the accuracy and precision necessary to determine compliance with the 

proposed limits. 

• 

14 
References 

1. CH2M Hill. June 2010. "Review of Available Technologies for the Removal of 

Selenium from Water." Prepared for the North American Metals Council. 

2. Envirogen 2011. Treatment of Selenium-Containing Coal Mining Wastewater 

with Fluidized Bed Reactor Technology. 

3. EPA Method 300.0. Determination of Nitrate-Nitrite Nitrogen by Automated 

Colorimetry. Revision 2.0. August 1993. 

4. EPA Method 353.2. Determination of Nitrate-Nitrite by Automated Colorimetry. 

Revision 2.0. August 1993. 

5. EPA 2000a. Development Document for Final Effluent Limitations Guidelines 

and Standards for the Landfills Point Source Category, EPA-821-R-99-019. 

6. EPA 2000b. Development Document for Effluent Limitations Guidelines and 

Standards for the Centralized Waste Treatment Industry - Final, EPA-821-R-00-

020. 

7. EPA 2010. NPDES Permit Writers' Manual, Chapter 5. Technology-Based 

Effluent Limitations. 

8. EPA. Technical Development Document (TDD) for the Proposed Effluent 

Limitations Guidelines and standards for the Steam Electric Power Generating 

Point Source Category, EPA-821-R-13-002, Docket ID EPA-HQ-OW -2009-

0819-2257. 

9. EPA. CW A Methods Update Rule for the Analysis of Effluent; Proposed Rule, 

80 Fed. Reg. 8956 (Feb. 19, 2015). 

10. Sonstegard, J., 1. Harwood, T. Pickett, D. Johnson, 2008. "Full Scale Operation 

ofGE ABMet® Biological Technology for the Removal of Selenium from FGD 

Wastewaters," presented at the 2008 International Water Conference, IWC08-31 . 

• 

15 

29142.070312 EMF_ US 564 71 083v4