NPDES PERMITTING: CURRENT DEVELOPMENTS AND STRATEGIES FOR NEGOTIATING PERMIT TERMS AND CONDITIONS

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1 NPDES PERMITTING: CURRENT DEVELOPMENTS AND STRATEGIES FOR NEGOTIATING PERMIT TERMS AND CONDITIONS Remarks of Stephen N. Haughey, Esq. FROST BROWN TODD LLC 301 E. Fourth Street, Suite 3300 Cincinnati, Ohio (513)

2 I. CURRENT DEVELOPMENTS IN NPDES PERMITTING A Numeric Nutrient Criteria 1. Federal a. Florida b. U.S. EPA s rejection of petition to develop technology-based numeric nutrient standards under the CWA secondary treatment standards c. U.S. EPA s rejection of petition to develop numeric nutrient criteria for all of the Mississippi River basin states, including Ohio d. Chesapeake Bay TMDL litigation 2. Ohio (1) Separate challenge by environmental groups to the legal basis under the CWA to allow trading programs as a means to comply with nutrient point source loading reductions in TMDLs (Food & Water Watch and Friends of the Earth v. U.S. EPA, 10/03/12) a. Status of numeric criteria for lakes, rivers and streams b. OEPA s efforts to develop criteria that take into account habitat and biological health, as opposed to the reference stream approach originally recommended by U.S. EPA 2

3 (1) The problem is that physical factors, such as sedimentation/ scouring, flow augmentation, habitat, canopy, temperature, and stream morphology have also been well documented as causes of accelerated eutrophication, toxic/nuisance algal blooms, and depressed biocriteria scores for fish and macroinvertebrates. (2) When attempting to regulate phosphorus at low concentrations, it is extremely difficult to differentiate cause-effect relationships between phosphorus discharges and avoiding these adverse impacts, versus the presence of these other physical factors that cause the same adverse impacts. (3) In the end, defensible criteria are required in order to support permit decisions based on reasonable potential to exceed the criteria. B. Revised TDS Criteria in Ohio 1. Current WQS is 1500 mg/l, but some states have 500 mg/l, and OEPA rumored in 2012 to be working on data to support potential revised standard around mg/l. 2. POTWs not designed to remove significant TDS. 3. Current WQS driven by macroinvertebrate impacts, but many physical stream factors also directly impact macroinvertebrate scores. 3

4 Run for cover! The nutrient and TDS limits are coming! The nutrient and TDS limits are coming! 4

5 C. If and when new nutrient and/or TDS criteria arrive, owners/operators of Ohio s POTWs will have several more likely options available with which to face the prospect of new limits: 1. 5

6 6 2.

7 7 3.

8 8 4.

9 D. Revisions to MS4 Permitting Requirements 1. U.S. EPA is under June 2013 deadline to propose post-construction stormwater rule for incorporation into revised Phase II stormwater permits for large, medium and small MS4s. 2. New rule will impose more inspection requirements on owners and operators of MS4s, and require that new construction meet stringent runoff standards that the MS4s will have to enforce as a term of their new general permit. E. TMDL-Based Flow Limits for MS4s to Reduce Sediment Runoff into Steams? 1. No, at least not at this time. Virginia Department of Transportation v. U.S. EPA, Case No. 1:12-CV-775, Memorandum Opinion, 1/13/13. The language of the CWA does not allow flow to be used as an indicator pollutant in TMDL-based permit decisions. 9

10 F. Enforcing Narrative Criteria in the Absence of Numeric Nutrient Criteria Impact of Upper Blackstone Water Pollution Control Abatement District v. U.S. EPA, Appeal No , U.S. Sup. Ct. Petition for Cert. G. Proposed Revisions to OEPA s Wastewater Rules (OAC Chapter ) 1. Revising OAC (C) to allow issuance of renewal permits even if the permit holder is not currently in compliance with the existing permit. II. STRATEGIES FOR NEGOTIATING PERMIT TERMS AND CONDITIONS A. Projected effluent quality (PEQ) and the role of your data. 1. Representative data a. Your effluent data is perhaps the most important and influential parameter in determining what your next set of permit limits will be when your permit comes up for renewal. The effluent data that you have generated over the life of your permit, and effluent data you have generated separately as part of your permit renewal application, will be evaluated by Ohio EPA, and screened as appropriate, and then determinations will be made regarding your average and maximum projected effluent quality (PEQ) for your individual parameters. 10

11 b. As long as you generate at least one effluent data point that is equal to or exceeds the detection level that applies to that parameter, Ohio EPA is required, with some exceptions, to determine the maximum and average PEQ for that parameter. OAC (D). c. Your effluent data must, however, be selected and reviewed in a manner the best represents the magnitude and variability for each pollutant parameter as projected for the applicable term of the new permit. OAC (D)(1). In this regard, the most recent five years of data must be reviewed and used unless an alternative period better represents the projected effluent quality from your POTW. For example, the last five years of MOR data do not need to be used if, for example, an upgrade or expansion to the POTW took place three years ago and, as a result, only the last three years of MOR data are representative of the PEQ of your discharge. 11

12 d. Because of staffing and funding limitations, a permit renewal application may be submitted several years before the permit renewal process begins and a draft renewal permit is issued. MOR data and permit renewal application data may become non-representative during the interim. It is up to you to make the best argument possible for the most representative time period for your effluent data. 2. Outliers a. Extreme outliers and other data anomalies resulting from collection, analysis or recording errors or non-repeated plant operation or discharge conditions, can by eliminated from your effluent database. OAC (D)(1)(b). Ohio EPA has a guidance document that sets forth a screening process for outliers and consideration of multiple effluent databases and small data sets. Modeling Guidance No. 1 sets forth these procedures. However, you are free to use an alternative, scientifically defensible statistical method in order to evaluate your effluent data in an effort to demonstrate more accurate long-term variability of your effluent quality. OAC (D)(2)-(3). 12

13 If you do not propose a different statistical method to evaluate the data, Ohio EPA will apply Modeling Guidance No. 1 by default. That Guidance employs a very conservative procedure that results in the minimum number of extreme data points be rejected from the data set. 3. Small databases a. The default procedure by which Ohio EPA evaluates very small databases (down to as low as a single data point) can result in a grossly inflated calculation of your maximum and average PEQ. Under a Modeling Guidance No. 1, the fewer the number of effluent data points, the greater the presumed variability of the effluent quality for that parameter and, as a result, the larger the fudge factor ( F ) that is applied to the calculation of the maximum and average PEQ. b. If you submit a permit renewal application that includes a single sample result for a parameter that you do not currently monitor as part of your permit, and you report that single result as a concentration above the applicable detection limit, the Agency will multiply that single result by a fudge factor (F) of 6.2 in order to calculate your maximum PEQ for that particular pollutant parameter. 13

14 c. With small effluent databases, Ohio EPA does not have enough data to determine long-term daily or monthly average variability. Thus, the Agency assumes that the effluent quality is highly variable, and therefore employs the highest factor for the smallest database. Too often this results in your receiving new draft monitoring requirements and/or numeric limits for pollutant parameters based on nothing more than the single data point that you submitted as part of your renewal application. B. Group classification of your data 1. Determining whether there is reasonable potential for your effluent parameters to cause to contribute to an exceedance of water quality criteria (WQC). 14

15 15 a. The importance of your effluent data becomes apparent when Ohio EPA then determines whether there is reasonable potential for your effluent to cause or contribute to an exceedance of applicable WQC. If the maximum or average PEQ for any pollutant parameter is > 25% of the applicable maximum or average WQC that applies to that parameter, Ohio EPA is required to proceed further to develop a preliminary wasteload allocation (WLA) (also referred to as a preliminary effluent limit (PEL)). If all available effluent data for a parameter are below applicable detection limits, then the process generally stops and no maximum or average PEQ is calculated, no PEL is calculated, and no limits or monitoring requirements will be imposed.

16 16 b. Once Ohio EPA has calculated a maximum and average PEQ for your effluent parameters, the Agency must determine what the applicable WQC are for each of your parameters. During this process, several assumptions are employed depending on the parameter being evaluated. For example, for metals whose WQC are hardness-based, Ohio EPA calculates the applicable in-stream hardness depending on the source of the hardness data and the size of the database. OAC (E). The importance here is that the higher the in-stream hardness, the higher the applicable WQC. If the hardness data for the stream is limited to a database of 10 values or less, Ohio EPA uses the arithmetic mean. For larger databases, it uses the median value. If the critical low flow of the receiving stream during drought conditions is zero or near zero, the hardness of your effluent (assuming that there is data) will be used to determine the applicable WQC for all hardness-based metals.

17 c. For ammonia, the applicable toxicity-based WQC varies depending on the temperature and ph of the receiving stream. Therefore, in order to determine what toxicity-based ammonia criteria apply to your discharge, Ohio EPA generally looks at the 75 th percentile values for temperature and ph in your receiving stream during the applicable summer and winter portion of the year. Once again, if your receiving stream has a critical low flow during drought conditions of zero or near zero, the correct ph and temperature to use in order to determine the applicable ammonia WQC are those for your effluent. d. For other pollutant parameters, Ohio EPA will determine the applicable WQC tables set forth in OAC and OAC to 34. The criteria will vary depending on whether your discharge is to a stream that is in the Ohio River basin or in the Lake Erie basin, and will also vary depending on the particular use designation assigned to your receiving stream. As a general rule, Lake Erie basin standards are somewhat more stringent than the Ohio river basin standards due to the impact of U.S. EPA s Great Lakes Initiative (GLI) and the fact that a lake is not a free-flowing stream. 17

18 Also, as a general rule, the criteria become more stringent as the use designation changes in order to protect more sensitive or endangered aquatic species. For example, warmwater habitat criteria are generally less stringent than exceptional warmwater habitat criteria, which in turn are generally less stringent than coldwater habitat criteria. The reason is that different use designations seek to promote different types of balanced aquatic populations, some of which are much more sensitive to pollutant loadings. e. At the conclusion of the calculation of maximum and average PEQ values for your effluent and determination of the applicable WQC, Ohio EPA develops average and maximum preliminary effluent limitations (PEL) that would apply to your pollutant parameters, and then compares those PEL values to your maximum and average calculated PEQ values. The end result is the group classification of your individual pollutant parameters into 1 of 5 groupings, ranging from Group 1 to Group 5. OAC (A). 18

19 (1) A pollutant is classified as Group 5 and receives a water qualitybased effluent limit (WQBEL) if the average or maximum PEQ is > the average or maximum PEL, respectively. Pollutant parameters are also classified as Group 5 if the average or maximum PEQ is > 75% of the average or maximum PEL, respectively, and the total loading of that pollutant downstream from your discharge is > 75% of the loading capacity of the receiving water for that particular pollutant. (2) A pollutant is classified as Group 4, for which only a monitoring requirement is imposed, if the average or maximum PEQ is > to 50% of the average or maximum PEL, respectively. For Group 4 pollutants, a tracking requirement is added to the permit, so that Ohio EPA is notified if the discharge reaches a certain level. (3) A pollutant is classified as Group 3 if the average or maximum PEQ is < 50% of the average or maximum PEL. Group 3 pollutants receive only a monitoring requirement. 19

20 (4) A pollutant is classified as Group 2 if the maximum or average PEQ is < than 25% of the maximum or average PEL. Importantly, monitoring requirements shall not be recommended for any Group 2 pollutant. OAC (B)(5). (5) A pollutant is classified as Group 1 if insufficient available data was present to develop numeric WQC. An example might be if there is no hardness data for a stream, from which to determine the applicable WQC for metals. f. This group classification process demonstrates why it is so important that you review all of your effluent data very carefully and work hard to ensure that the most representative data is being used, and that all possible outliers are being rejected from your database. It also underscores the importance of conducting your own evaluation of the in-stream databases that Ohio EPA evaluated in order to determine applicable WQC, for example, in-stream hardness, ph, and temperature. 20

21 C. The mass balance equation On paper, the mass balance equation is relatively simple and straightforward. It is used to develop WLAs for the conservative, toxic parameters. Simply put, the total pollutant loading that is allowable in a stream cannot be exceeded by the total pollutant loading being added to the stream. The mass balance equation is as follows: WQC (Q effluent + Q upstream ) Q upstream (WQ upstream ) Q effluent WQC is the water quality criteria for your parameter in a concentration form. Q effluent is the design flow of your POTW. Q upstream is the amount of the stream s critical low flow that applies to your parameters. WQ upstream is the background (upstream) water quality for your parameter in a concentration form. 21

22 1. Importance of stream critical low flow a. As you can see from the above equation, the amount of in-stream flow used to develop the preliminary WLA is critically important. Because Ohio EPA must protect the receiving stream during extreme drought conditions, the mass balance equation uses critical low flows in the determination of the WLA. The amount of the critical low flow varies depending on the parameter being evaluated, and on the relative size of your discharge to the critical low-flow discharge in the receiving stream. Different critical low flows are used for different parameters. For example, for ammonia toxicity, the applicable critical low flow is the 7Q10 for chronic limits and 1Q10 for acute limits. For wildlife criteria, the critical low flow that is used is the 90Q10 flow of the stream. 22

23 23 b. You may or may not be entitled to use 100% of the critical low flow of the receiving stream. If the critical low flow of your receiving stream is less than or equal to 10 times the design flow of your POTW, 100% of the critical low flow of the stream is used in the equation, based on the assumption that there is rapid and complete mixing of your discharge with the receiving stream. On the other hand, if the ratio is much larger, a smaller percentage of the critical low flow of the stream is used, based on the assumption that mixing is a much slower process between your effluent and the receiving stream. As a general rule, only 10% of the critical low flow of the Ohio River is used when determining WLA for average WQC, and 1% when determining WLA for maximum WQC. The importance of this factor is two-fold. First, it is important that you closely evaluate the USGS stream flow gauging information at the time of your permit renewal, in order to ensure that the correct critical low flow is being used to develop preliminary wasteload allocations. Second, the determination of critical low flow in a receiving stream is a constantly changing parameter. As additional river flow information is generated each day, the database changes from which the critical low flow value is determined. Sometimes an outdated time period is used to determine the critical low flow for the receiving stream.

24 2. Upstream or background concentrations a. The important thing here is that background concentrations will generally improve as additional or new treatment is provided upstream, and as additional stormwater controls are implemented upstream. Often Ohio EPA s database for in-stream background concentrations dates back to when the last water quality survey was done for the receiving stream, which, at times, can be five or more years ago by the time your permit comes up for renewal. Under such circumstances, the background concentrations are often no longer representative of what the current background concentrations are in your receiving stream. In such circumstance, additional sampling should be done to demonstrate what the present background concentrations are above your discharge. 3. POTW design flow and loadings a. The important thing here is that if actual effluent flow will differ significantly from original design flow during the life of the permit, the Director is supposed to use the actual effluent flow rather than original design flow. OAC (A)(4)(a). 24

25 D. Hardness-based metals (Cu, Zn, Cr, Pb, Ni, Cd) 1. There are two important things here. First, the higher the hardness of the receiving stream, the higher the allowable discharge of these metals. Therefore, ensuring that the correct hardness value is used to determine the applicable WQC for these metals is very important in determining whether you receive monitoring requirements and/or effluent limits. Second, these criteria are based on avoiding toxicity associated with the dissolved form of the metal present in the water column in the receiving stream. But, the applicable analytical method measures the total recoverable form of these metals, which includes both the toxic, dissolved form, and the non-toxic particulate or bound form of the metal. Depending on the sources of these metals in your influent, your discharge may have a relatively high ratio of the nontoxic particulate or bound form of these metals to the toxic, dissolved form. 25

26 2. Because Ohio EPA is required to establish permit limits based on the total recoverable form of these metals, the Agency allows the use of a dissolved metals translator (DMT) to adjust permit limits based on the percentage of the metal in your discharge in the particulate or bound form. A site-specific DMT can be calculated for your discharge. In the alternative, Ohio EPA has established some DMTs for certain receiving streams segments in Ohio and uses those as a default DMT. OAC (E). Ohio EPA has modeling guidance with which to develop a site-specific DMT (Modeling Guidance No. 2). 3. In certain situations, your effluent may have a higher average hardness value than the receiving stream. If the critical low flow in the receiving stream is zero or near zero, the hardness of your effluent should be used to determine the applicable WQC for these metals. 26

27 4. While the use of a DMT for hardness-based metals can result in a higher numeric effluent limit, by far the most significant methodology used to obtain higher limits for these metals is the use of what is termed as the water effects ratio procedure. Effectively, that procedure develops site-specific WQC for your stream segment using your receiving stream as the test water for the aquatic species. This particular procedure can result in a several fold increase in your effluent limits, but does take a considerable amount of time to develop the necessary data. E. Modeling to establish limits for DO-related parameters (DO, ammonia and CBOD) 1. Distinguished from ammonia toxicity a. Ammonia is regulated in two distinct ways by Ohio EPA. The first is ammonia toxicity. The tables found at OAC (Tables 7-2 through 7-8) are toxicity-based criteria that are dependent on the seasonal ph and temperature of the receiving stream. If your permit limits for ammonia are established based solely on avoiding ammonia toxicity, the limits will almost always be considerably higher, often above 5.0 mg/l, to as high as even 9 mg/l, and sometimes even higher. 27

28 28 b. For the vast majority of POTW permit holders in Ohio, ammonia limits are set at substantially more stringent concentrations based on the need to maintain a minimum DO concentration in the receiving stream. This is particularly true for smaller streams and rivers. Bacteria and other organisms consume oxygen as they digest (nitrify) ammonia and feed on organic loadings, thereby potentially causing in-stream DO concentrations to fall below the established minimum associated with the particular use designation. For that reason, depending on the size of your receiving stream, the quality of its canopy, the nature of its substrate, and the elevation gradient, ammonia limits based on DO can be considerably more stringent than ammonia limits based on the avoidance of ammonia toxicity.

29 2. Possible trade offs a. In determining ammonia and CBOD limits based on maintenance of applicable minimum DO criteria, Ohio EPA uses a modeling program into which different values for ammonia and CBOD are imputed and resulting DO concentrations are determined. The important thing here is that these three parameters are interrelated and permit holders can request that different limits be applied for the parameters, which can result in significant cost savings for a POTW. For example, accepting a higher DO limit than, for example, a minimum limit of 5 mg/l, can result in your receiving higher ammonia and CBOD limits. The addition of post-aeration to increase DO concentration in the final effluent can be a considerably less expensive step than modifying or expanding other segments of the treatment process. 29

30 F. Impact of water quality stream survey reports and fact sheets 1. Whether a water quality stream report was prepared for your receiving stream is important for two reasons when your permit comes up for renewal. First, if your draft renewal permit did not take into account the findings of a recent water quality survey report for your receiving stream, important information regarding improved background conditions, recent attainment of applicable biological and chemical criteria, and changes in stream flow can be obtained from a water quality survey report, and can be valuable in influencing the final terms and conditions of your permit. In the alternative, if the draft renewal permit was issued taking into account the findings of an outdated water quality stream survey report, the background concentrations, achievement of biological and chemical criteria, and other findings in the stream report, may no longer be representative and may not reflect the current water quality conditions in the stream. 30

31 2. Ohio EPA is required to issue a fact sheet with the draft permit issued for all major POTWs. The term major POTW is generally defined as a POTW with a design flow with at least 1.0 mgd, but also includes draft permits that contain a sewage sludge land application plan, as well as all draft permits that are the subject of wide-spread public interest or that raise major issues. The fact sheet is required to set forth the significant factual, legal, methodological and policy questions that were considered in preparing the draft permit. 40 CFR Fact sheet shall include: a. A description of a type of discharge that is the subject of the draft permit; b. A summary of the basis for each draft permit condition, including references to applicable statutory and regulatory provisions and supporting references to the administrative record developed to support the draft permit; 31

32 c. A statement of basis why any requested variance or alternatives to required effluent standards or WQC are not justified; and d. A description of procedures for reaching a final decision on the draft permit, including the beginning and ending date of the comment period, and a summary of the procedures for requesting a hearing on the final permit. 3. Without a fact sheet, the recipient of a draft renewal permit has little, if any, information from which to determine where the proposed terms and conditions came from or how they were generated or developed. 32

33 G. Establishing monitoring frequencies for effluent parameters 1. The cost of effluent monitoring can be a significant expense over the life of a 5-year permit. In addition to the expense, monitoring frequencies that vary considerably from parameter to parameter can present a major labor problem for a POTW, because the potential hodge podge of inconsistent and variable sampling requirements can cause gross inefficiencies in terms of the labor that is necessary to take the required samples. For these reasons, permit holders should not ignore proposed monitoring requirements and frequencies in a draft renewal permit. 33

34 2. In general, Ohio EPA uses three permit guidance documents (Permit Guidance Nos. 1, 3 and 11) to establish influent, effluent, upstream and downstream monitoring requirements, as well as sludge monitoring requirements for POTWs. Permit Guidance No. 1 applies specifically to sanitary discharges, and sets forth recommended monitoring requirements for effluent, influent, upstream and downstream, and sludge. Importantly, generally speaking, the amount and frequency of monitoring requirements are based on the average dry weather design flow of the POTW, and, with respect to the sludge, the dry weight of sludge disposed in a calendar year. The requirements can be adjusted and can vary from the recommended levels on a case-by-case basis based on factors such as: a. Type of treatment system and the effectiveness of the O & M program for the POTW; b. The dilution available in the receiving stream; 34

35 c. The potential for the discharge to cause violations of WQC; d. Whether the POTW participates in the Municipal Compliance Maintenance Program; e. The actual discharge volume of an under-loaded treatment plant; and f. The relevance of the particular monitoring requirement to the day-today operations and performance of the plant. 35

36 36 3. The important point here is the Ohio EPA has considerable discretion to vary from the guidance-driven recommendations for monitoring frequencies. In particular, Ohio EPA has historically been very receptive to requests to harmonize the monitoring requirements to avoid unnecessary labor expenses. In addition, Ohio EPA has also been receptive to significant reductions in monitoring frequencies if the effluent data shows consistent and excellent performance, even if the effluent data does not yet support removing the monitoring requirement completely.

37 37 4. Permit Guidance No. 3 is used by Ohio EPA on a case-by-case basis to establish upstream and downstream sampling requirements when, for example, (a) biomonitoring requirements are included in the permit, (b) there is a need to assess upstream water quality that is related to a particular permit term or condition (an example is monitoring hardness upstream for purposes of your metals limits), (c) where there is a need to assess downstream water quality that is related to a particular permit term or condition (an example is if Ohio EPA has agreed to establish a mixing zone), and (d) if Ohio EPA has agreed to establish flow-based, tiered permit limits that require regular monitoring of the upstream or downstream flow in the receiving stream. The importance of this permit guidance is that it demonstrates that Ohio EPA should not establish potentially expensive and burdensome upstream and downstream monitoring requirements just because the Agency wants to collect additional data in order to evaluate instream water quality. Too often proposed upstream and downstream monitoring requirements are based on nothing more than a desire to generate additional stream data in the absence of a water quality survey report.

38 H. The dreaded As 1. Antibacksliding a. The concept of antibacksliding strikes unnecessary fear into permit holders. While generally speaking, once WQBELs are established in a permit, they cannot be made less stringent in a later permit, the more correct application of the term is that such limits cannot be removed in later permits without a good reason. Under Ohio EPA s rules, permits can be reissued or modified to contain effluent limits that are less stringent than the previous permit under the following conditions: (1) Material and substantial additions or alternations to the POTW occurred after the permit was issued, which additions or alterations justify the application of less stringent effluent limits. 38

39 (2) Information is now available that was unavailable at the time the permit was issued, and which information would have justified less stringent limits had it been available at the time the permit was issued. (3) For technology-based limits, technical mistakes or mistaken interpretations of law were made in issuing the permit. (4) A less stringent limit is necessary because of events over which the permit holder has no control and for which there is no other reasonably available remedy. (5) The permit holder has installed the treatment equipment required to meet the new effluent limits and has operated and maintained the equipment properly, but has nevertheless been unable to achieve the effluent limits. 39

40 (6) If the WQC are being maintained and the request for less stringent limits is submitted to the applicable requirements of Ohio EPA s antidegradation rule. 2. The important thing is that there are numerous exceptions to the general requirement that renewed, reissued or modified permit cannot contain less stringent limits than the previous permit. 40

41 I. Antidegradation 1. Ohio EPA s antidegradation rule impacts draft renewal permit terms and conditions in several ways. As a general rule, any request in a renewal application for an increase in mass loading of any pollutant parameter will trigger some level of review under the antidegradation rule. The antidegradation review is required to be performed upon submission of any control document in which the request for a mass loading increase is submitted. Therefore, the review can take place in the context of a PTI application to build or expand the POTW, in the context of a permit renewal application, and in the context of an application submitted to modify an existing permit. 41

42 42 2. For conventional parameters (i.e., CBOD, TSS, ammonia, DO, and chlorine residual), the antidegradation rule typically affects POTWs in two ways. First, if the permit holder is already subject to the BADCT limits set forth in Table 5-1 to the antidegradation rule, any expansion to the POTW will trigger an antidegradation rule review and, potentially, may result in proposed permit limits that are even more stringent than the BADCT limits set forth in the existing permit. If the decision is made for whatever reason to hold mass loadings constant in the receiving stream, the existing permit limits will be reduced, in terms of their concentration, in an amount that is proportional to the requested increase in design flow for the POTW. This can result in permit terms that are considerably more stringent than the BADCT limits set forth in Table 5-1.

43 3. If the existing permit limits for the POTW are less stringent than the BADCT limits, a request to expand the POTW and increase its design flow will most likely result in the imposition of more stringent limits set at levels between the existing permit limits and the BADCT limits, at a level that is proportional to the amount of the design flow increase for the POTW. In other words, a proportional, flow-based calculation is done, resulting in permit limits based on a mix of the BADCT limits and the existing permit limits. 4. The other way that the antidegradation rule will affect your next permit is if you request an increase in mass loading and your receiving stream is subject to a set aside of remaining pollutant assimilative capacity. For streams that are classified as outstanding state waters or superior high quality waters under the rule, a certain percentage of the remaining assimilative capacity of the stream has been set aside and cannot be used in order to accommodate any expansion or increase in design flow. This can result in more stringent permit limits during a future permit renewal. 43

44 5. If a request for a mass load increase is submitted in conjunction with a permit renewal application, more stringent permit limits may be imposed if the Director determines that there is insufficient social and economic justification (SEJ) for the requested mass load increase. J. Key Areas to Focus on During the Draft Permit Stage 1. Proper group classification of your parameters 2. Avoiding monitoring requirements or effluent limits based on the one hit wonder or small database 3. Discarding non-representative effluent data, based on outlier data points and/or upgraded treatment processes during the term of your current permit 4. Reducing excessive, unnecessary (and expensive) monitoring 44

45 5. Calculation errors 6. Trading off DO, CBOD and ammonia limits 7. Reducing/eliminating biomonitoring 8. Analyzing your MOR data before the permit renewal application is submitted. Why not ask OEPA for modified terms in your new permit before it is drafted???? 45