### Matuszko, Jan From: Sent: To: Cc: Subject: Attachments:



### All: 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 

### A venue, NW Washington, DC 20037 Phone: 

### F

ax : 202/955-1547 202/778

-220 1

Confidentiality Notice: The inf onnation contained in this e-mail and any attachments may be legally privil eged and confidential. lf you are not n intended recipient, you are hereby notified that any dissemination, distribution or copying ofthi e-mail is strictly prohibi ted. Ifyou have received this e-mail in error, please n tify the sender and pennanentl y del ete the e-mail and any attachments immediately. You should not retain, copy or use this e-mai I or any attachment for any purpose, nor disclose aU or any part of the contents to any other person. Thank you.



### •

1

### Steam Electric Effluent Guidelines: Proposed Nitrates Limits for FGD Wastewater Are Unnecessary and Will Present Significant Analytical Issues

•

### I. Introduction UWAG 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 ofnitrate/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 ofFGD wastewater for selenium removal assures removal ofall but trace amounts ofnitrate/nitrite in FGD wastewater. The non-biological treatment systems being developed for possible FGD wastewater application also require reduction ofnitrate/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 ofdilution 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/NitriteLimits 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 ofphysical/chemical and biological treatment. The biological treatment portion ofthe system targets selenium removal; but, as a co-benefit ofthat treatment, it also removes all but trace amounts ofnitrate/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 ofnaturally occurring bacteria are fixed to a bed ofgranular 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 ofselenium
.... The order use ofelectron acceptors follows the more energetically favorable reactions first
....

. . . The presence ofeither 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 ofmicroorganisms and electron donors
.... [H]igh levels ofnitrate
... will be preferentially reduced before selenium, and must be removed before effective selenium reduction will occur. Envirogen, 20II, pp. 4-5
. The preferential reduction ofoxygen and nitrates over selenium in biological treatment systems is well-accepted science. CH2M Hill explains the reduction priorities as follows: 

### •
2Some denitrifiers [i.e., types ofbacteria that can use nitrate as an electron acceptor] can use selenate or selenite as an electron acceptor but only in the absence ofoxygen and nitrate. Ifeither 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 oforganic 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
. Ifeither 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 ofNitrate/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 ofoxidants in the wastewater. As the ORP approaches 0 mV (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 ofbiological 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
3eta!., 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 ofthe 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 ofapproximately -80 to -250 mVs to achieve selenium reduction. Nitrate/nitrite reduction occurs in the range ofapproximately 20 mV s to -100 mV 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 ofnutrient provided must be in
excess ofthe 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 ofnitrate/nitrite prior to the removal ofselenium. 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 ofselenate and selenite in the ZVJ process is a similar mechanism to that ofthe 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 oftreatment 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 ofoxygen, nitrate and nitrite will compete with the reduction of selenium. CH2MHill 20l0, p. 4-45

- 4-48
. Therefore, oxygen, nitrate and nitrite must be removed first, to ensure adequate treatment for selenium. 

### 2. Degassing ofBiological 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 ofthe nitrate/nitrite reduction reactions. The denitrification that occurs within a biological treatment system may impact system performance by causing pockets ofnitrogen 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 ofthe pockets. 

### !d. Biological system manufacturers recommend regular degassing ofthe 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 ofthe system. Any failure to degas as recommended by the vendors would lead to exceedances ofselenium. 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 ofconcern (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 ofthe 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 ofeffective removals ofmany 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
....

6NPDES 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 ofother 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 ofpollutants 

### (e.g., tluoranthene as an indicator for a group ofpolyaromatic 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
. 

### •
71. 

### The Proposed Limits are Too Close to the MDL for Method 353.2 EPA proposed nitrate/nitrite (reported as N) regulatory limits of0.13 and 0.17 mg/1, for the monthly average and daily maximum, respectively. According to the current approved version ofMethod 353.2, the method has an "applicable range" of0.05 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 ofdeionized water. The proposed monthly average value for nitrate/nitrite of0.13 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).' IfEPA accepts a factor of3 times the MDL as an appropriate 

### quantitation limit, then it is inappropriate for EPA to promulgate a 

### compliance limit of0.13 mg/1, which is less than 3 times the method-specific MDL. And the proposed daily maximum of0.17 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 ofchloride than drinking, surface, domestic, and typica' l industrial wastes. The presence ofchlorides 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 ofthe 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). 8method 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 ofinterference. In summary, this method has limited applicability for FGD wastewaters. IfMethod 

### 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 ofnitrate/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 oftheir 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 ofthe co1 lumn is termed the "retention time." The size ofthe detector response is dependent on the amount ofthe specific analyte present- more analyte gives a larger peak. A common issue with IC is the interference oftwo 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 ofCl- in the 9example 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 ofthe 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. C hnlmltogram lhCMimg .,.aJan

## ..ana 1111 AS4A

### ceum (EPA Method 300
.0). Ret. Time lon mgJL 1.17 f· 2 1.73 

### C t 20 2

. .02 NOZ- 2 

## u s Br 2 3.20 

### N O

; 10 5.38 

### H POt 2 6.92 

## soz- 

## • 60

Interferences can be caused by substances with retention times that are similar to the anion ofinterest. Large amounts ofan anion, such as chloride (Cl-), can overlap the peak ofan 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 ofFGD 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 ofoperation, 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 ofnitrate 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 I0,000-15,000 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 IO,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 ofO.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. IIV. 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 ofthe FGD wastewater samples collected for EPA's study ofthe 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 ofeffluent from the biological treatment systems for nitrate/nitrate analysis, eight from each treatment plant. At each plant, these consisted offour successive days of sampling during one week (labeled "Day" samples in Table 3 below), followed by four other samplings ofa single sample each, all at least two months apart during the course ofa year (labeled "Month" samples in Table 3 below). EPA's laboratory assigned a reporting timit (or QL) of0.1 mg/1 to all ofthe FGD analyses for nitrate/nitrite. Using these data to calculate regulatory limits is problematic because 12 ofthe 16 samples analyzed were non-detects 

### (i.e., below the laboratory ML of0.1 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 Ofthe samples, only four results are quantified, and those values are barely above the laboratory ML. All four ofthe quantified results either equal or exceed the monthly average regulatory limit set by EPA.

12Basing regulatory limits on a very small dataset from two plants is not warranted. We know that biological treatment systems remove all but trace amounts ofnitrate/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 UWAG noted in its 2013 comments on the proposed rule, the chloride concentrations for Belews Creek and Allen ranged from 7,000 to 9, I00 mg/1and 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 bl owdown required and increases the chloride levels in the wastewater. In this scenario, chloride levels can range from I0,000 to 30,000 mg/1and can be as high as 50,000 mg/, Jdepending on the materials ofconstruction ofthe 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/1range) as indicated in Table 2 above. 

### VII. Conclusion For all ofthe 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 ofthe nitrate/nitrite must be removed before selenium can be adequately removed. This 13fact 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 ofthe 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 ofthe 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.



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14

### References 1. CH2M Hill. June 2010. "Review ofAvailable 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 ofNitrate-Nitrite Nitrogen by Automated Colorimetry. Revision 2.0. August 1993. 4. EPA Method 353.2
. Determination ofNitrate-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. CWA Methods Update Rule for the Analysis ofEffluent; 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
.



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