technical justification for industrial user local limits

City of Elkhart, Indiana Public Works & Utilities

Technical Justification for

Industrial User Local Limits

December 2012

This Sheet is Intentionally Blank

Table of Contents

City of Elkhart Technical Justification for Industrial User Limits, December 2012

i

Contents

1. Introduction 1-1

1.1. Background ................................................................................................................... 1-1 1.2. Description of Plant Processes ..................................................................................... 1-2 1.3. Pollutants of Concern .................................................................................................... 1-2 1.4. Development of Local Limits ......................................................................................... 1-4

2. Maximum Allowable Headworks Loadings 2-1

2.1. Preliminary Data Evaluation .......................................................................................... 2-1 2.1.1. Outliers ............................................................................................................... 2-1 2.1.2. Data Below Detection Level ............................................................................... 2-1

2.2. Plant Removal Efficiency .............................................................................................. 2-2 2.2.1. Removal Efficiency Calculation Methodologies and Values .............................. 2-2

2.3. Allowable Headworks Loadings .................................................................................... 2-3 2.3.1. NPDES AHL ....................................................................................................... 2-4 2.3.2. Land Application of Sludge AHL ......................................................................... 2-4 2.3.3. Inhibition AHL ..................................................................................................... 2-4

2.4. Maximum Allowable Headworks Loading ..................................................................... 2-5

3. Maximum Allowable Industrial Loadings 3-1

3.1. Domestic Wastewater Sampling ................................................................................... 3-1 3.2. Industrial User Contributory Flow.................................................................................. 3-2 3.3. Maximum Allowable Industrial Loading ........................................................................ 3-2

4. Proposed Industrial User Limits 4-1

4.1. Considerations for Determination of Industrial User Limits .......................................... 4-1 4.2. Calculation of Allowable Industrial User Limits ............................................................. 4-2 4.3. Proposed Local Limits ................................................................................................... 4-2

4.3.1. Arsenic, Cadmium, Total Chromium, Copper, Lead, Silver, Zinc and Cyanide . 4-2 4.3.2. Mercury ............................................................................................................... 4-2 4.3.3. Nickel .................................................................................................................. 4-3 4.3.4. Molybdenum, Selenium and Phenol ................................................................... 4-3 4.3.5. FOG and TPH ..................................................................................................... 4-3

4.4. Potential Impact to Industrial Users .............................................................................. 4-4

Table of Contents


ii

Industrial User Limits Development Tables 1-1 Potential Pollutants of Concern ................................................................................... 1-3

Appendix A 2-1 Primary Plant Removal Efficiency Values 2-2 Overall Plant Removal Efficiency Values 2-3 Allowable Headworks Loading for NPDES Discharge Levels 2-4 Allowable Headworks Loading for Land Application of Sludge 2-5 Allowable Headworks Loading for Inhibition 2-6 Maximum Allowable Headworks Loadings 2-7 Comparison of Average Headworks Pollutant Load vs. MAHL

3-1 Average Domestic vs. Average Influent Pollutant Concentrations 3-2 Industrial Users and Contributory Flows 3-3 Maximum Allowable Industrial Loadings

4-1 Industrial User Concentrations with Peak Concentration Above Current Local Limit 4-2 Proposed Local Limits

Appendix B EPA Local Limits Spreadsheet Calculations


1-1

1. Introduction

1.1. Background

The Elkhart Wastewater Treatment Plant (WWTP) treats residential and industrial wastewater from the City of Elkhart, Indiana. The facility is a publicly owned treatment works (POTW), and its discharge to the St. Joseph River is regulated by the Indiana Department of Environmental Management (IDEM) under the National Pollutant Discharge Elimination System (NPDES) program. IDEM is authorized by the US Environmental Protection Agency (EPA) to implement the NPDES program in accordance with the federal Clean Water Act (CWA), also known as the Federal Water Pollution Control Act as amended. IDEM issued the NPDES Permit (No. IN0025674) renewal to the City of Elkhart effective May 1, 2012 with effluent limitations for various pollutants. This permit was subsequently revised by IDEM effective September 1, 2012, to incorporate modifications to discharge requirements for mercury as requested by the City under water quality standard variance provisions of the federal CWA.

The City of Elkhart implements an Industrial Pretreatment Program, approved by EPA Region 5. IDEM has not been given authorization by EPA for an approved State Pretreatment Program, and accordingly EPA Region 5 must review and approve local pretreatment programs and their modifications for POTWs in Indiana. The City’s pretreatment program includes a Wastewater Utility Use Ordinance with various general and specific prohibitions and restrictions. As part of its pretreatment program, the City has also issued Industrial Wastewater Discharge Permits to approximately 48 Significant Industrial Users (SIUs). The Wastewater Utility Use Ordinance and the Industrial Wastewater Discharge Permits include discharge limitations and monitoring requirements for various pollutants.

A key element of the pretreatment program is development and implementation of local industrial user discharge limitations (“local limits”), which prevent the introduction of pollutants into the POTW that would either interfere with the operation of the POTW, pass through the POTW, be incompatible with the POTW, or limit wastewater or sludge use options. A technical re-evaluation of the City’s existing local limits is also required by the NPDES permit, to be performed consistent with EPA’s local limits guidance document1. The City of Elkhart initiated this study to evaluate the adequacy of its existing local limits and to develop a technical justification for either revising or retaining the existing local limits for all appropriate pollutants of concern (POC).

1 Local Limits Development Guidance, EPA 833-R-04-002A, July 2004

Section 1

Introduction


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1.2. Description of Plant Processes

The City of Elkhart WWTP is a conventional biological activated sludge plant with anaerobic digestion of residuals. The City's wastewater is treated to meet NPDES Permit effluent limitations for conventional pollutants, CBOD5 and TSS, and ammonia. The plant is designed to treat an average daily flow of 20 million gallons per day (mgd) and a peak flow of 44 mgd.

Raw sewage enters the plant through two major trunk systems. One system brings the combined sewage from the City’s sewer service area, and enters the plant from the south. A second system, called the North Interceptor, was built in the early 1980s to service major industrial complexes in the City’s northwestern corridor. However, in 1998 and 2002 the major industrial contributors to this system closed operations, leaving the North Interceptor with nearly its full dry weather design capacity available. By 2004 it was operating at approximately 7 percent of its full-flow capacity.

Wastewater entering the plant passes through a bar screen and undergoes grit removal and primary treatment before entering the activated sludge process. The activated sludge process uses aeration, followed by clarification. The treated wastewater is disinfected with chlorine and then dechlorinated to remove any chlorine residual prior to discharge into the St. Joseph River.

Waste activated sludge from the biological treatment system is sent to gravity thickeners and then to anaerobic digesters. Primary sludge is pumped directly to the anaerobic digesters where it is mixed with and digested with the waste secondary sludge. The digested sludge is then dewatered using belt filter presses. Digested and dewatered sludge is disposed by one of three alternatives: land appliied to approved agricultural sites, composted with yard waste, or hauled to landfill.

1.3. Pollutants of Concern

The first step in the evaluation of local limits is the determination of appropriate POCs. For the current local limits development process, the City considered the following as potential POCs: pollutants with existing local limits, pollutants with an NPDES permit limit, pollutants with preliminary effluent limits as determined in the Wasteload Allocation Report2 (WLA), and recommended national pollutants of concern from the EPA guidance document. The following table lists the potential POCs considered for evaluation, and the determination by the City to use as initial POCs for this study.

2 Wasteload Allocation Report for the Elkhart WWTP (IN0025674, WLA001844), IDEM, July 11, 2011

Section 1

Introduction


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Table 1-1 Potential Pollutants of Concern

Potential POC

Current Elkhart Local Limit

Recommended National POC EPA Guidance

NPDES Permit

WLA Report

Initial POC for

Evaluation

Arsenic Y Y – – Y

Cadmium Y Y – Y Y

Chromium, Total Y Y – Y Y

Copper Y Y Y Y Y

Cyanide Y Y – Y Y (a)

Lead Y Y – Y Y

Mercury Y Y Y Y Y

Molybdenum – Y – – Y (b)

Nickel Y Y – Y Y

Selenium – Y – – Y (c)

Silver Y Y – Y Y

Zinc Y Y – Y Y

Total Phenols – Y – – Y

FOG Y – – – Y (d)

TPH – – – – Y (d)

BOD5 Y Y – – N (e)

TSS Y Y – – N (f)

NH3 Y Y – – N (g)

Notes:

(a) Historic data shows no significant industrial discharge source of CN. Evaluate whether CN should be continued or removed as local limit.

(b) Evaluate Molybdenum as possible POC because it is included in 503 regs

(c) Evaluate Selenium as possible POC because it is included in 503 regs. However, not believed to be discharged to the WWTP in sufficient amounts to cause sludge disposal problem.

(d) Evaluate whether FOG should be removed as LL and replaced with TPH, based upon EPA Local Limits Development Guidance information.

(e) Based upon historical plant data, BOD loadings are significantly less than plant capacity. BOD5 local limit is unnecessary.

(f) Based upon historical plant data, TSS loadings are significantly less than plant capacity. TSS local limit is unnecessary.

(g) Historic data shows no significant industrial NH3 discharge source. NH3 local limit is unnecessary.

Section 1

Introduction


1-4

1.4. Development of Local Limits Industrial user local limits have been developed following the methodology presented in EPA’s guidance document for development of local limits. The following steps in the evaluation and development of the City of Elkhart’s local limits have been performed:

n Calculation of the Maximum Allowable Headworks Loadings (MAHL) to the City’s WWTP for each POC. EPA’s guidance document defines MAHL as “an estimate of the upper limit of pollutant loading to a POTW intended to prevent pass through or interference” with biological treatment processes or sludge disposal. This is described in Section 2 of this report.

n Calculation of the Maximum Allowable Industrial Loadings (MAIL) for each POC to the WWTP. These calculations represent the estimate of the maximum pollutant loading to the WWTP that can be received from its controlled sources (i.e., industrial users). This is described in Section 3 of this report.

n Allocation of MAILs and calculation and subsequent proposal of a set of local limits for all POC that will protect the City’s WWTP – to avoid non-compliance with NPDES permit discharge limitations, to comply with sludge disposal requirements for land application, and to avoid biological process inhibition within the WWTP. This is described in Section 4 of this report.

The supporting calculations performed and discussed in Sections 2, 3 and 4 for development of MAHLs, MAILs and proposed local limits are presented in a series of tables in Appendix A. Each table is described and referenced in the associated section of this report.

The US EPA Region 5 Local Limits Spreadsheet3 calculation tables are presented in Appendix B. These calculations are equivalent to those discussed in this report and presented in Appendix A, although this spreadsheet does not include some of the underlying development and supporting calculations (e.g., plant removal efficiencies, industrial user contributory flows, and comparisons with actual headworks loadings). One additional table has been added to the EPA spreadsheet, to present a summary of the calculated local limits (Table 10).

3 Microsoft Excel spreadsheet downloaded from Region 5 Water Industrial Pretreatment web site: http://www.epa.gov/region5/water/npdestek/npdprta.htm#spreadsheet

Section 2

Maximum Allowable Headworks Loadings


2-1

2. Maximum Allowable Headworks Loadings

2.1. Preliminary Data Evaluation 2.1.1. Outliers

The collected background and plant data was analyzed to determine if outliers exist. An outlier identification test recommended in the EPA guidance document was used: the inter-quartile range (IQR) method.

The IQR method employs the inter-quartile range of the data set (i.e. the difference between the values of the 3rd quartile [75th percentile] and the 1st quartile [25th percentile]) to determine outliers in a data set. This method was applied to concentration values in each pollutant’s data set that were reported as above the analytical detection level (DL). Data points that were more than 1.5 times the inter-quartile range below the 1st quartile or above the 3rd quartile were considered outliers.

Using the IQR method, a few outlier values were identified and removed from the collection system sampling data. Judgment was employed when determining potential outliers, in order to not remove too many data values. A total of eight outlier values were removed from the total collection system data set of more than 600 values. No outliers were removed from the plant database used for calculation of removal efficiency.

2.1.2. Data Below Detection Level A number of the pollutant concentrations were reported as Below Detection Level

(BDL), which is below the level of detection for the respective pollutant analysis. The IQR and MR statistical methods were employed on the data when concentrations were reported as BDL. If all or nearly all of the data values were reported as BDL, then one half of the pollutant’s DL was used to represent the concentration.

The probability plotting (MR method) was used to determine appropriate surrogate values for concentrations reported as BDL. This method is recommended and described in the EPA guidance document.4 In this method, each concentration, including those reported as BDL, in a pollutant’s data set is given its average possible rank in the data set. Each reported concentration and its rank are then plotted and a linear trend line is applied to the data. The average possible rank of concentrations reported as BDL is then inserted into the equation of the trend line to determine those

4 For a detailed explanation of this method and an example ranking a sample data set, refer to EPA Local Limits Development Guidance, (July 2004), Appendix Q.

Section 2



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concentrations’ appropriate substitute value. If a substitute value was found to be negative, zero was used in its place.

2.2. Plant Removal Efficiency

The first step in calculating the Maximum Allowable Headworks Loadings (MAHL) for the City of Elkhart’s WWTP is to determine the primary treatment and overall plant removal efficiency for each POC. The primary treatment and overall plant removal efficiencies represent the percentage of influent pollutant loading that has been removed through the primary treatment stage and across the entire WWTP, respectively. Removal efficiency values for each POC are fundamental inputs to the MAHL calculation methodology.

City staff collected WWTP influent, primary effluent and final effluent samples from April 16-22 and May 14-21, 2012. The analytical results were evaluated and analyzed to determine the appropriate plant removal efficiencies to be used in subsequent MAHL calculations.

2.2.1. Removal Efficiency Calculation Methodologies and Values To calculate the overall plant removal rates for the POC, three different

calculation methodologies are presented in Section 5 of the EPA guidance document to analyze the treatment plant’s data: average daily removal efficiency (ADRE), mean removal efficiency (MRE) and the decile method. All three methods were used for the Elkhart evaluation (if available data was sufficient for each method’s use), and the results were compared.

The ADRE method requires paired data values (i.e. an influent sample paired with a lagged effluent sample to reflect the hydraulic residence time of wastewater passing through the treatment plant). For the calculations, a one-day (24-hour) sample collection lag was used to approximate the typical hydraulic residence time through the plant. The basic equation for the ADRE method is:

Where: R = Removal efficiency, as decimal I = POTW influent pollutant concentration at headworks, mg/l E = Effluent pollutant concentration, mg/l n = Paired observations, numbered 1 to N

The ADRE method is sensitive to variation in daily removal efficiencies, and accordingly the EPA suggests that this calculation not be used if less than ten data pairs are available.

( )N

IEIR nnnå -

=/

Section 2



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The MRE method is more versatile than the ADRE method. It can be used with either daily paired concentrations or unpaired concentrations from the influent and effluent. The MRE method averages all influent and effluent concentrations separately first before calculating the removal efficiency. The MRE method’s basic equation is:

Where: R = Removal efficiency, as decimal I = POTW influent pollutant concentration at headworks, mg/l E = Effluent pollutant concentration, mg/l R = Plant influent samples, numbered 1 to R t = Effluent samples, numbered 1 to T

The decile method sorts daily removal efficiency data from highest to lowest and

calculates the percentage of the daily removal efficiency above or below a specified removal efficiency. This methodology is somewhat similar to a data set median calculation, and provides some understanding of the likelihood of certain removal efficiencies. For the purposes of this justification, the daily removal efficiency for each pollutant at the fifth decile, or median, was used as the representative removal efficiency of the pollutant. The decile method requires use of at least nine paired data values (influent value paired with a lagged effluent value, as are used in the ADRE method).

Table 2-1 and Table 2-2 contain the calculated primary and overall plant removal efficiencies using the three calculation methodologies for the WWTP. The pollutant removal efficiency selected to represent each pollutant of concern was based on availability of data for each method calculation, with the decile method preferred over other methods and the MRE method preferred over the ADRE method. Seven pollutants for primary removal efficiency and three pollutants for overall removal efficiency contained insufficient data to calculate a plant removal efficiency value by one or more of these methods. In these instances, a reported removal value from past EPA studies of priority pollutants from other POTWs was used.5

2.3. Allowable Headworks Loadings

The Allowable Headworks Loading (AHL) is the estimated pollutant load that can be received by a POTW at its headworks that will not cause the POTW to exceed a specific criterion. AHLs were determined for NPDES permit effluent limits (or preliminary

5 Removal data from past POTW pollutant removal studies was reported in EPA’s 1987 Local Limits Development Guidance document. This same data was reported in the 2004 guidance document. Raw data from the original POTW removal studies was re-analyzed by EPA and published in the EPA Development Document for the CWT Point Source Category document (2000). The removal data as presented in the 2000 EPA CWT document is considered more representative of the actual POTWs performance.

r

tr

IEI

R-

=

Section 2



2-4

effluent limitations (PEL) from the WLA Report), land application of sludge disposal regulations, and inhibition of the treatment plant’s biological treatment processes (activated sludge and nitrification).

2.3.1. NPDES AHL Table 2-3 contains the calculated AHLs based on effluent limits in the City of Elkhart’s NPDES permit issued by IDEM. For POCs with no NPDES limit, the PEL determined by IDEM in the WLA Report was used instead. The equation for AHLs based on NPDES permit effluent limits is:

Where: AHLNPDES = AHL based on NPDES permit limit (or PEL), lbs/day CNPDES = NPDES permit limit, mg/l QPOTW = POTW average flow rate, MGD RPOTW = Overall plant removal efficiency, as decimal 8.34 = Unit conversion factor

2.3.2. Land Application of Sludge AHL Table 2-4 contains the calculated AHLs based on Federal regulation 40 CFR Part 503. This regulation contains sludge criteria for disposal by land application. The equation for AHLs based on land application of sludge is:

Where:

AHLSldg = AHL based on sludge, lbs/day CSldg = Sludge criteria, mg/kg dry sludge QSldg = Total sludge flow rate to disposal, dry metric tons/day RPOTW = Overall plant removal efficiency, as decimal 0.0022 = Unit conversion factor

2.3.3. Inhibition AHL Table 2-5 contains the calculated biological treatment inhibition AHLs for potential inhibition to both activated sludge and nitrification biological treatment processes. The more stringent of the two calculated AHLs for each pollutant was selected as the City of Elkhart WWTP’s inhibition AHL.

The equation for activated sludge and nitrification inhibition AHLs is:

( )( )( )( )POTW

POTWNPDESNPDES R

QCAHL

-=

134.8

( )( )( )POTW

SldgSldgSldg R

QCAHL

0022.0=

Section 2



2-5

Where: AHLInhib = AHL based on activated sludge or nitrification inhibition,

lbs/day CInhib = Inhibition threshold level6 for activated sludge or nitrification,

mg/l QPOTW = POTW average flow rate, MGD Rprim = Primary removal efficiency, as decimal 8.34 = Unit conversion factor

2.4. Maximum Allowable Headworks Loading

The Maximum Allowable Headworks Loading (MAHL) for a pollutant at a POTW is the most stringent of the calculated AHLs for that POTW. Table 2-6 shows the AHLs and the MAHL for each potential pollutant of concern at the City’s WWTP.

Table 2-7 compares the MAHLs with the average influent pollutant load at the plant headworks. Section 6.1.1 of EPA Local Limits Development Guidance recommends that local limits are needed for a pollutant if its influent loading is greater than 60% of its MAHL. None of the City’s 15 potential POCs have average influent loadings greater than or equal to 60% of their respective MAHL. The average mercury influent loading is the highest, at 52% of its MAHL. This suggests that the City’s pretreatment program implementation (including enforcement of current limits) as well as the pretreatment behavior of the City’s industrial users is adequately protecting the WWTP, and these factors have helped to ensure the City’s NPDES permit compliance.

While the City’s industrial users are generally not having issues with compliance, it is not recommended that pollutants with existing local limits should have their limits removed. Removal of existing local limits could signal that there is no need to provide pretreatment, or remove incentive for good pretreatment system performance – neither of which would be desired.

6 Inhibition threshold levels for activated sludge and nitrification are values between the minimum and maximum literature values reported in EPA Local Limits Development Guidance, (July 2004), Appendix G.

( )( )( )prim

POTWInhibInhib R

QCAHL

-=

134.8

Section 3



3-1

3. Maximum Allowable Industrial Loadings

3.1. Domestic Wastewater Sampling

Wastewater from uncontrolled sources (i.e., domestic users [residential and commercial] and inflow and infiltration) accounts for approximately 94% of the total influent flow at the City of Elkhart’s wastewater treatment plant. It is necessary to estimate the average pollutant contributions of these uncontrolled sources in order to determine the pollutant loadings that may be allocated to industrial users. Accordingly, sampling and analyses of four locations in the collection system were performed.

The 9th St. Interceptor, Eastlake Lift Station, Knights Inn Lift Station and Sunset Avenue locations in the City of Elkhart were selected as representative domestic (non-industrial) wastewater sampling sites, since the wastewater tributary to these four locations is non-industrial and essentially all residential/commercial in origin. The locations represent a combination of residential (both older and more recent) with some commercial, and include both separate and combined sewer areas.

Each domestic wastewater sampling site was sampled for approximately two weeks: April 16-22, and May 14-21, 2012. As described in Section 2-1, the data were evaluated for outliers and BDL values. The IQR and MR statistical methods were employed on the domestic sampling data when concentrations were reported as BDL. The average domestic wastewater concentrations for each POC are presented in Table 3-1, as well as US EPA domestic wastewater literature values7. Since the four sites were considered to have wastewater representative of the City’s domestic sewer users, the data from the sites were averaged to represent the typical domestic pollutant concentrations for the entire sanitary sewer system. Table 3-1 compares these average pollutant concentrations to each site’s average pollutant concentrations and WWTP influent pollutant concentrations.

While most of the average domestic pollutant concentrations were below the average plant influent pollutant concentrations, arsenic, copper, lead, zinc and cyanide averaged higher domestic concentrations than the plant influent concentrations. Assuming that the average industrial pollutant concentration is at least as high as the average plant influent concentration, the influent concentration is the maximum value that any average domestic concentration could be. For a reasonable estimate of the domestic (non-industrial) concentrations of these four pollutants (arsenic, copper, lead,

7 US EPA domestic wastewater literature values were taken from EPA Local Limits Development Guidance, (July 2004), Appendix V. The values in Appendix V were originally reported in May 1991.

Section 3



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zinc and cyanide) the domestic concentration for each were assigned a value equal to 90% of their respective average influent concentration.

3.2. Industrial User Contributory Flow

It is necessary to determine which industrial users are contributory to the industrial flow of each POC at the wastewater treatment plant. All industrial users’ sampling data from January 5, 2009 to December 28, 2011 was analyzed. For each industrial user, its average discharge concentration for each pollutant was compared with a ‘contributory threshold’ criterion equal to 1.5 times the maximum domestic (non-industrial) concentration for the respective pollutant. If the industrial user’s pollutant concentration exceeded this threshold, the industry was considered to be a contributory industry for that pollutant. For nickel and silver, because of the numbers of industries with relatively low concentrations of these metals, the contributory threshold criterion was set equal to 10 times the maximum domestic concentration.

The average daily industrial flows of each contributory industry were then added together to determine the industrial user contributory flow rate for each POC. Table 3-2 presents a listing of the contributory industries, along with their respective average daily industrial flows and the total contributory industrial flow for each POC. As shown in this table the total average discharge flow for all industries – regardless of their contributory or non-contributory status – was 1.0 MGD. The highest average contributory flow for any POC was 0.25 MGD (for chromium), which indicates that most industrial users do not contribute most POCs.

3.3. Maximum Allowable Industrial Loading

The maximum allowable industrial loading (MAIL) for each POC is an estimate of the maximum pollutant loading to the POTW that can be received from its industrial users. Table 3-3 contains the calculated MAILs for pollutants at the City’s WWTP.

The equation to calculate MAIL for each pollutant is:

Where:

MAIL = Maximum allowable industrial loading, lbs/day MAHL = Maximum allowable headworks loading, lbs/day SF = Safety factor. A value of 0.1 (10%) was used for all pollutants. DPL = Average domestic pollutant load, lbs/day

( )( ) DPLSFMAHLMAIL --= 1*

Section 3



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The equation for average domestic pollutant load is:

Where: DPL = Average domestic pollutant load, lbs/day DPC = Average domestic pollutant concentration, mg/l QPOTW = POTW average flow rate, MGD QIU, POTW = Average industrial user contributory flow rate to POTW, MGD 8.34 = Unit conversion factor

( )( )( )34.8,POTWIUPOTW QQDPCDPL -=

Section 4

Proposed Industrial User Limits


4-1

4. Proposed Industrial User Limits

4.1. Considerations for Determination of Industrial User Limits

There is considerable conservatism ‘built-in’ to the local limits development calculation procedures as used with the methodology of the EPA Local Limits Development Guidance document. This results in calculation of technically justifiable local industrial user discharge limitation values that should be fully protective of pass through and interference at the City’s wastewater treatment plant.

Following is a summary discussion of several aspects of the local limits calculation methodology used as well as the existing loading circumstances for the City of Elkhart’s collection system. These factors together result in conservative and fully protective industrial user discharge local limits for the City’s WWTP.

n It is highly unlikely that all Industrial Users would discharge wastewater pollutants at concentrations close to the calculated ‘safe’ local limits simultaneously. Hence for any given day, it is reasonable to expect that a significant fraction of the maximum allowable industrial loading for each pollutant is ‘un-used’.

n A safety factor is used to adjust the calculated MAHL to compensate for potential data uncertainties that may otherwise result in inaccurate local limits calculations. The safety factor is applied as a deduction from the calculated MAHL prior to calculation of the MAIL. USEPA generally recommends a ten percent safety factor as a minimum, although the guidance document notes that either higher or no safety factors may be appropriate for specific pollutants in individual cases. We have used a safety factor of ten percent for calculation of the MAILs. This adds an additional ‘reserve’ into the calculated local limits.

n None of the POCs had an actual average influent load-to-MAHL percentage greater than the EPA recommended threshold of 60%. These very low ratios of actual pollutant loads to corresponding MAHLs indicate that considerable ‘reserve’ load capacity exists with the current Industrial User discharges and current local limits.

At present, the existing Industrial Users are generally able to comply with the existing limits. Table 4-1 presents a comparison of IU discharge data for 2009 through 2011, showing a summary of all industrial users that had monitoring concentrations greater than the City’s current local limits. This table presents the three highest discharge monitoring sample results for any industry that had one or more reported discharge values that exceeded the current local limit. As seen in this summary table, there were relatively few industries with discharge exceedances during this three year

Section 4



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period. It is the City’s intent to continue to apply standards that sufficiently protect City facility treatment operations and the environment while not presenting an unreasonable economic barrier to industry.

Accordingly, it is the objective of this technical justification to retain existing limits or establish new local limits (as appropriate) that are fully protective of the City’s WWTP, yet which will not be more stringent than necessary for its industrial users. Establishing local limits that go beyond meeting these objectives may result in unnecessary pretreatment and/or waste management and disposal costs for IUs.

4.2. Calculation of Allowable Industrial User Limits

Allowable industrial user limits for each pollutant of concern were calculated using the contributory industrial flow (as described in Section 3-2 and presented in Table 3-2) for each pollutant. These calculated allowable limits are presented in Table 4-2. Calculated allowable limits represent the highest discharge concentration that could be technically justified for contributing industrial users for each pollutant at the WWTP, based upon the maximum headworks loading methodology.

4.3. Proposed Local Limits

Based on consideration of the factors and issues presented in this document, we recommend adding new proposed local limits or retaining current local limits as shown in Table 4-2. This table shows current local limits as well as the calculated allowable limits for each pollutant. All proposed local limit values have been rounded to not greater than two significant figures. Following is a brief discussion of recommended local limit values for the various POCs.

4.3.1. Arsenic, Cadmium, Total Chromium, Copper, Lead, Silver, Zinc and Cyanide

The calculated allowable limits (as shown in Table 4-2) for arsenic, cadmium, total chromium, copper, lead, silver, zinc and cyanide are each greater than the respective current local limits for these pollutants. Hence, the existing local limits are adequate to protect the WWTP. It is recommended that the existing local limit values for each of these pollutants should be retained.

4.3.2. Mercury The calculated allowable limit for mercury is considerably lower than the current local limit (8.6 µg/l versus 20 µg/l, as shown in Table 4-2). This is a result of the new lowered NPDES permit limit for mercury. The existing modified NPDES permit (effective September 2012) has a mercury variance based effluent limit of 1.6 ng/l, versus the originally issued permit limit of 1.3 ng/l. Because of the mercury variance and the requirement to implement a mercury pollutant minimization program in order to eventually achieve the lower water quality based effluent limit, the MAHL calculation has

Section 4



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used the more stringent 1.3 ng.l NPDES effluent limit. It is recommended that the local limit for mercury be changed to a new value of 9 µg/l (i.e., the calculated allowable limit rounded to one significant figure).

4.3.3. Nickel The calculated allowable limit for nickel is lower than the current local limit

(2,910 µg/l versus 4,100 µg/l, as shown in Table 4-2). The current total actual influent loading of nickel is substantially less than the calculated MAHL (approximately 28% of the MAHL, as shown in Table 2-7). Since there have not been problems or issues with process inhibition, pass through/NPDES compliance or sludge disposal for nickel, and since the actual total influent loading is substantially less than the MAHL, it is recommended that the existing local limit for nickel of 4,100 µg/l be retained.

4.3.4. Molybdenum, Selenium and Phenol Limits for molybdenum, selenium and phenol were not calculated, as few if any

industrial users currently discharge these pollutants. There is no apparent need for local limits for these pollutants. It is recommended that no new limits be established for any of these three.

4.3.5. FOG and TPH Oils and greases (O&G) are not a single chemical substance but rather a group

of substances with similar physical properties that are determined by a laboratory analytical method using phase separation into a solvent. O&G includes materials of vegetable, animal and mineral origin. O&G can be further classified into two main components, which are differentiated by their polar or non-polar characteristic in laboratory analysis. Polar, animal- and vegetable-based materials are designated as fats, oils and greases (FOG). Non-polar, petroleum-based hydrocarbons, are determined by the analytical method named Total Petroleum Hydrocarbon (TPH).

While both FOG and TPH can have impacts to collection systems and/or WWTPs, FOG is generally biodegradable whereas TPH is generally resistant to biodegradation. TPH is much more likely to pass through or cause interference at a POTW. The pretreatment regulations at 40 CFR 403.5(b)(6) prohibit the discharge of “petroleum oil, non-biodegradable cutting oil, or products of mineral oil origin in amounts that will cause interference or pass through.” The EPA guidance document states that “most POTWs have adopted 100 mg/L as their local limit for TPH because of its history of such a limit being protective of the treatment plant and receiving stream.”

The City of Elkhart currently has a local limit for FOG of 100,000 µg/l (100 mg/l). As noted, vegetable or animal based FOG is generally biodegradable, and there does not appear to be a substantial justification for industrial user local limits at this relatively stringent level. Experience with many food processing industries has shown that it can

Section 4



4-4

be difficult to continuously and reliably achieve pretreatment effluent limit for FOG of 100 mg/l, yet there generally are very little adverse impacts on POTWs. A somewhat higher local limit would be reasonable.

One source of FOG that is sometimes problematic for a POTW – and particularly for POTW collection systems – are FOG from food service establishments. The EPA local limits guidance document in Section 5.3.3 states: “Animal-based and vegetable-based oil and grease (polar concentrations) are more difficult to regulate when the major source is a large number of restaurants and fast-food outlets in the collection system.” The Guidance document in Section 8.3 adds: “The use of controls other than numerical limitations may be a more appropriate way to address the problem of FOG from non-SIUs”. These controls include the development and implementation of best management practices (BMPs) and the continuous upkeep of grease traps and grease interceptors. The City of Elkhart’s pretreatment program currently requires and enforces such requirements for all commercial food service establishments, since they are a primary source of FOG discharged into the City’s collection system.

It is recommended that the existing local limit for vegetable- and animal-based FOG be raised to 200,000 µg/l (200 mg/l). It is recommended that a new local limit of 100,000 µg/l (100 mg/l) be established for TPH.

4.4. Potential Impact to Industrial Users

Based on a summary review of recent monitoring data from the City’s industrial users, it is believed that all should be able to continue compliance with the recommended local limits. It is not expected that any of the industrial users would need to make significant changes to their facilities in order to assure continuing compliance with their industrial user permit discharge limitations.

Appendix A

Local Limits Development Calculations


A

APPENDIX A

Local Limits Development Calculations: Tables for Sections 2, 3 and 4

Average Daily

Removal Efficiency

Mean Removal Efficiency

Decile Method

Literature Removal Values

Primary Removal Efficiency

Pollutant (4) (5) (6) (7)Arsenic (1) -- -- -- -- 1%Cadmium (2) -- -- -- 15% 15%Chromium 30% 33% 41% 27% 41%Copper 31% 30% 26% 22% 26%Lead -- 9% -- 57% 9%Mercury 47% 59% 58% 10% 58%Molybdenum 0% 1% -- -- 1%Nickel 56% 52% 68% 14% 68%Selenium (1) -- -- -- -- 1%Silver 17% 32% 30% 20% 30%Zinc 11% 19% 13% 27% 13%Cyanide (3) -- -- -- 27% 27%Phenol (3) -- -- -- 8% 8%FOG (1) -- -- -- -- 1%TPH (1) -- -- -- -- 1%

Notes: - Data from 2012 was used to calculate the Primary Removal Efficiency.

Table 2-1 Primary Removal Efficiency Values

(4) Average Daily Removal Efficiency = average of the pollutant's daily primary removal efficiencies. If there are less than 10 daily values available, the EPA recommends using Mean Removal Efficiency because it is generally less sensitive to variation in daily removal efficiencies. Since all pollutants have less than 10 daily values available, this method is Not Applicable (NA) to determining Primary Removal Efficiency.

(5) Mean Removal Efficiency = (average daily influent pollutant concentrations - average daily primary effluent pollutant concentrations) ÷ average daily influent pollutant concentrations.

(6) Decile Method = median of the daily primary removal efficiencies. The Decile Method requires at least nine daily values to be an appropriate means of determining a removal efficiency. Since all pollutants have less than nine daily values, this method is Not Applicable (NA) to determine Primary Removal Efficiency.

(7) Literature Removal Values are the median Primary Removal Efficiency values taken from EPA Local Limits Development Guidance , (July 2004), Appendix R. Various prior studies reporting removal rates were originally summarized and reported in the previous EPA Local Limits Development Guidance (1987).

(1) No data from the WWTP was available to calculate pollutant's Plant Removal Efficiency and Literature Removal value was not available. Therefore, a conservative Plant Removal Efficiency of 1% was used.

(2) The calculated Plant Removal Efficiencies were negative. Therefore, the pollutant's Literature Removal Value was used.(3) No data from the WWTP was available to calculate the pollutant's Plant Removal Efficiency. Therefore, the pollutant's Literature Removal Value was used.

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-1 Primary Removal December 2012

Average Daily

Removal Efficiency

Mean Removal Efficiency

Decile Method

EPA (1987) Removal Values

EPA (2000) Removal Values

Plant Removal Efficiency

Pollutant (3) (4) (5) (6) (7)Arsenic 34% 51% 50% 45% 66% 50%Cadmium (1) -- -- -- 67% 90% 90%Chromium 94% 94% 95% 82% 80% 95%Copper 92% 93% 94% 86% 84% 94%Lead 27% 44% 58% 61% 78% 58%Mercury 92% 96% 97% 60% 90% 97%Molybdenum 22% 21% 30% -- 19% 30%Nickel 96% 96% 96% 42% 51% 96%Selenium (2) -- -- -- 50% 34% 34%Silver 92% 94% 95% 75% 88% 95%Zinc 66% 68% 68% 79% 79% 68%Cyanide (1) -- -- -- 69% 70% 70%Phenol 37% 54% 49% 90% 95% 49%FOG 100% 100% 100% -- -- 100%TPH 8% 99% -- -- -- 99%

Notes: - Data from 2012 was used to calculate the Overall Plant Removal Efficiency.

(7) "Final POTW Percent Removals" values taken from EPA Development Document for the CWT Point Source Category (2000), Table 7-5. These data are based upon a reevaluation of the various prior studies reporting removal rates originally summarized and reported in EPA Local Limits Guidance Manual on the Development of Local Discharger Limitations Under the Pretreatment Program (December 1987).

(6) Literature Removal Values are the median Activated Sludge Removal Efficiency values taken from EPA Local Limits Development Guidance, (July 2004), Appendix R. Various prior studies reporting removal rates were originally summarized and reported in the previous EPA Local Limits Development Guidance (1987).

Table 2-2 Overall Plant Removal Efficiency Values

(3) Average Daily Removal Efficiency = average of the pollutant's daily plant removal efficiencies. If there are less than 10 daily values available, the EPA recommends using Mean Removal Efficiency because it is generally less sensitive to variation in daily removal efficiencies. For pollutants with less than 10 daily values available, this method is Not Applicable (NA) to determining Plant Removal Efficiency.

(4) Mean Removal Efficiency = (average daily influent pollutant concentrations - average daily final effluent pollutant concentrations) ÷ average daily influent pollutant concentrations.

(5) Decile Method = median of the daily plant removal efficiencies. The Decile Method requires at least nine daily values to be an appropriate means of determining a removal efficiency. Since all pollutants have less than nine daily values available, this method is Not Applicable (NA) to determining plant Removal Efficiency.

(2) No data from the WWTP was available to calculate the pollutant's Plant Removal Efficiency. Therefore, the pollutant's Literature Removal Value was used.

(1) The calculated Plant Removal Efficiencies were negative. Therefore, the pollutant's Literature Removal Value was used.

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-2 Plant Removal December 2012

NPDES Discharge Levels

Overall Plant Removal Efficiency

Allowable Headworks

Loading (1) (2) (3)

Pollutant ug/l lbs/dayArsenic -- -- --Cadmium 15 0.90 20Chromium 1300 0.95 3590Copper 38 0.94 88.5Lead 160 0.58 50.2Mercury 0.0013 0.97 0.0052Molybdenum -- -- --Nickel 820 0.96 2890Selenium -- -- --Silver 0.37 0.95 1.0Zinc 290 0.68 120Cyanide 22 0.70 9.8Phenol -- -- --FOG -- -- --TPH -- -- --

Notes: - Average WWTP Influent Flow = 15.8 mgd. (2009-2012)

(2) Mercury NPDES limit of 0.0013 ug/l is from the original NPDES permit, effective May 1, 2012. Subsequently, a mercury water quality variance was approved and a modified permit was issued with a mercury limit of 0.0016 ug/l.

(1) NPDES Discharge Levels for development of Local Limits PreliminaryEffluent Limitations (PEL) from Wasteload Allocation Report for the ElkhartWWTP (IDEM, July 2011). The NPDES Discharge Levels are presented in theNPDES Permit in mg/l, not ug/l. The conversion between ug/l and mg/l: 1 ug/l =0.001 mg/l.

(3) AHL = (NPDES Disch.Level x Avg. Infl. Flow x 8.34) ÷ (1 - Plant RemovalEfficiency)

Table 2-3 Allowable Headworks Loading for NPDES Discharge Levels

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-3 NPDES AHL December 2012

Part 503Monthly Average

Pollutant Limit

Plant Removal Efficiency

Allowable Headworks

Loading

(1) (2)Pollutant mg/kg lbs/dayArsenic 41 0.50 1.1Cadmium 39 0.90 0.58Chromium -- -- --Copper 1500 0.94 21Lead 300 0.58 7.0Mercury 17 0.97 0.2Molybdenum 75* 0.30 3.4Nickel 420 0.96 5.9Selenium 100 0.34 3.9Silver -- -- --Zinc 2800 0.68 55Cyanide -- -- --Phenol -- -- --FOG -- -- --TPH -- -- --

Notes:

WWTP average sludge production (Feb 2010 - Jan 2012) = 13,472 lbs/dayfrom WWTP biosolids reports to EPA

Table 2-4 Allowable Headworks Loading for Land Application of Sludge

(2) AHL = ((Monthly Avg. Pollutant Limit ÷ 1,000,000) x WWTP Sludge Prod.) ÷ Plant Removal Efficiency

(1) All Monthly Average Pollutant Limit values were taken from 40 CFR 503.13Table 3 (except Molybdenum, which was taken from 40 CFR 503.13 Table 1).

* Molybdenum only has a ceiling limit (503.13 Table 1) and does not have a "clean" sludge concentration (503.13 Table 3).

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-4 Land App AHL December 2012

Activated Sludge Nitrification Anaerobic

Digestion Primary Plant Activated Sludge Nitrification Anaerobic

Digestion

(1) (2) (3) (4) (4) (5) (6)Pollutant mg/l mg/l mg/l lbs/day lbs/day lbs/day lbs/dayArsenic 0.1 1.5 1.6 1% 50% 13.3 200 1.6 1.6Cadmium 5 5.2 20 15% 90% 776 807 11 11Chromium 50 1.0 -- 41% -- 11,200 224 -- 224Copper 1 0.25 40 26% 94% 178 44 21 21Lead 50 0.5 340 9% 58% 7,270 73 284 73Mercury 0.5 -- -- 58% -- 159 -- -- 159Molybdenum -- -- -- -- -- -- -- -- --Nickel 2.5 5 136 68% 96% 1,030 2,060 68 68Selenium -- -- -- -- -- -- -- -- --Silver -- -- 40 -- 95% -- -- 20 20Zinc 5 0.3 400 13% 68% 758 46 284 46Cyanide 5 0.4 50 27% 70% 904 72 34 34Phenol 125 4 -- 8% -- 17,900 574 -- 574FOG -- -- -- -- -- -- -- -- --TPH -- -- -- -- -- -- -- -- --

Notes: - Average Influent Flow = 15.8 mgd. (2009-2012)

- Sludge Flow Rate to Digesters = 0.058 mgd (based on digester solids mass balance worksheet data from City)

(6) Allowable Headworks Loading was calculated as the most stringent Inhibition-based Allowable Headworks Loading.

(5) Inhibition-based AHLs for Anaerobic Digestion = (8.34 x Inhb. Threshold x Sludge Flow to Digester) ÷ Plant Removal Efficiency.

Inhibition Threshold Levels Allowable

Headworks Loading

(1) Inhibition Threshold Levels are approximately the median Activated Sludge values taken from EPA Local Limits Development Guidance , (July 2004), Appendix G.

(2) Inhibition Threshold Levels are approximately the median Nitrification values taken from EPA Local Limits Development Guidance , (July 2004), Appendix G.

(3) Inhibition Threshold Levels are approximately the median Anaerobic Digestion values taken from EPA Local Limits Development Guidance , (July 2004), Appendix G.

Table 2-5 Allowable Headworks Loading for Inhibition

(4) Inhibition-based AHLs for Activated Sludge and Nitrification = (8.34 x Inhib.Threshold x Avg. Infl. Flow) ÷ (1 - Prim. Removal Efficiency).

Removal Efficiencies Inhibition-based AHLs

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-5 Inhibition AHL December 2012

Table 2-5 Table 2-7 Table 2-11NPDES Land

Application Inhibition

Pollutant lbs/day lbs/day lbs/day lbs/dayArsenic -- 1.1 1.6 1.1 Land ApplicationCadmium 20 0.6 11 0.6 Land ApplicationChromium 3590 -- 224 224 Inhib NitrifCopper 89 21 21 21 Inhib DigestLead 50 7.0 73 7.0 Land ApplicationMercury 0.0052 0.2 159 0.0052 NPDESMolybdenum -- 3.4 -- 3 Land ApplicationNickel 2890 5.9 68 5.9 Land ApplicationSelenium -- 3.9 -- 3.9 Land ApplicationSilver 1.0 -- 20 1 WLAZinc 120 55 46 46 Inhib NitrifCyanide 9.8 -- 34 9.8 WLAPhenol -- -- 574 574 Inhib NitrifFOG -- -- -- N/ATPH -- -- -- N/A

MAHL is minimum value of the respective AHLs.

Maximum Allowable

Headworks Loading

Limiting Factor

Table 2-6 Maximum Allowable Headworks Loadings

Allowable Headworks Loadings

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-6 MAHL December 2012

Maximum Allowable

Headworks Loading

Average Influent

Pollutant Concentration

Average Influent

Pollutant Load

Percentage of MAHL

(1) (2)Pollutant lbs/day µg/l lbs/dayArsenic 1.1 1.5 0.2 18%Cadmium 0.6 0.5 0.1 11%Chromium 224 11 1.4 0.6%Copper 21 73 9.6 47%Lead 7.0 3.3 0.4 6.3%Mercury 0.0052 0.0205 0.0027 52%Molybdenum 3.4 7.0 0.9 27%Nickel 5.9 12 1.6 28%Selenium 3.9 -- -- --Silver 1.0 0.8 0.1 10.9%Zinc 46 98 12.9 28%Cyanide 9.8 0.003 0.0004 0.004%Phenol 574 5.5 0.7 0.1%FOG N/A 13208 1743 --TPH N/A 359 47 --

Notes: - Average Influent Flow = 15.8 mgd. (2009-2012)

(1) Average Influent Pollutant Load = Avg. Infl. Poll. Conc. x Avg. Infl Flow x 8.34.

(2) Percentage of MAHL = (Avg.Infl. Poll. Load ÷ MAHL) x 100%.

Table 2-7 Comparison of Average Headworks Pollutant Load vs. MAHL

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 2-7 MAHL Comparison December 2012

Minimum Maximum Average (2) (3) (4) (5)

Pollutant ug/l ug/l ug/l ug/l ug/l ug/l ug/l ug/l ug/l

Arsenic 0.4 88 7 7.1 6.2 1.1 1.0 3.8 1.5

Cadmium 0.8 110 8 0.6 0.4 0.1 0.3 0.3 0.5

Chromium <1 1200 34 12 4.4 2.2 2.2 5.4 10.8

Copper 5 740 140 373 329 164 82 229 73

Lead 1 2040 58 11 6.3 4.1 3.6 6.3 3.3

Mercury <0.1 54 2 0.013 0.022 0.017 0.005 0.014 0.021

Molybdenum -- -- -- 3.2 1.7 0.6 1.2 1.7 7.0

Nickel <1 1600 47 3.7 0.7 0.5 0.5 1.4 12

Selenium -- -- -- --

Silver 0.7 1052 19 1.0 0.3 0.5 0.07 0.5 0.8

Zinc 10 1280 231 380 204 145 76 196 98

Cyanide 10 370 82 3.0 3.5 3.0 3.9 3.3 0.003

Phenol 0.02 0.03 0.025 5.5

FOG -- -- -- 13,208

TPH -- -- -- 359

Notes: - All domestic sampling took place April 16 to May 20 , 2012.

- WWTP Influent Concentrations were collected from April 16 to May 21, 2012.

(5) Collection system 4 location is characterized as residential / commercial / separate sewers. Samples are 24-hr time-composites.

Average Collection System Pollutant Concentrations

WWTP Influent

US EPA Literature Values

(1)

(4) Collection system 3 location is characterized as residential / commercial / separate sewers. Samples are 24-hr time-composites.

(1) US EPA Literature Values taken from EPA Local Limits Development Guidance, (July 2004), Appendix V. Values in Appendix V originally published in 1991. (The US EPA Literature Values are presented in the Guidance Document in mg/l, not ug/l. The conversion between ug/l and mg/l: 1 ug/l = 0.001 mg/l.)

(2) Collection system 1 location is characterized as residential / partial combined sewers. Samples are 24-hr time-composites.

(3) Collection system 2 location is characterized as single-family residential / partial separate sewers. Samples are 24-hr time-composites.

Table 3-1 Average Domestic vs. Average Influent Pollutant Concentrations

CS1: 9th St. Interceptor

CS2: Eastlake L.S.

CS3: Knights Inn L.S. CS4: Sunset

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 3-1 Collection System December 2012

Table 3-2 Industrial Users and Contributory Flows

Elkhart WWTP Industrial Users Indu

stria

l Use

rFl

ows

(MG

D)

Cya

nide

, ug/

L

AACOA 0.18788 x xAmerican Electronic Components 0.00072 xAMPRO 0.00153 xAnderson Silver Plating 0.00535 x xAtlas Chem Milling 0.0152 x xAtwood Mobile Products 0.0067B-D Industries 0.0041 x xContinental Industries, Incorporated 0.0019Continental Mirrored Graphics 0.0038Crown International 0.0029 xD & W, Incorporated 0.0106 xDexstar Wheel Company 0.0069 xDexter Chassis 0.0167 x xDometic 0.0045 x xDynamic Metal Forming 0.0016E. K. Blessing Company 0.0053ECM Photo-Tooling 0.0020 x x x xEarthmovers Landfill 0.0272 x x xElkhart Environmental Processing 0.0756 x x xElkhart General Hospital 0.1318Elkhart Plating Co. 0.0181Elkhart Products 0.0228 xGemeinhardt 0.0020George Weston Bakeries 0.0230Gunite Corporation 0.0088 x xHuntington Alloys Corporation 0.0060Indiana Micro Etch 0.0019KIK/APG Main 0.0636 xKIK/APG North 0.0274KIK/APG South 0.0126KIK/APG West 0.0565Liftco 0.0039Manchester Tank 0.0063McDowell Enterprises 0.0043 x x x xMOR/ryde 0.0074 xNorco Industries, Inc. 0.0055Norfolk Southern Railway Company 0.0388Plumrose 0.0868R C Industries, Incorporated 0.0034SAPA 0.0091 x xSiemens (87-01) 0.0123Temple Products of Indiana 0.0062 x x x xUMI 0.0043 xVincent Bach Co. 0.0301Welch Packaging 0.0011 xWinona Powder Coating 0.0065Elkhart County Landfill 0.0190Zurn/U.S. Brass 0.0020

Industrial User Contributory Flow (MGD) 1.002 0.203

Notes:

(2) The Industrial User Contributory Flow for Phenol, FOG, TPH and TCLP is 0, since no IUs had a single concentration above the average domestic pollutant concentration plus 3 standard deviations or 1.5 times maximum domestic pollutant concentration if the aforementioned was less than the maximum domestic pollutant concentration.

(1) (1)

(1) The Industrial User Contributory Flow for Molybdenum and Selenium is 0, since no IUs were sampled for these pollutants.

Zinc

, ug/

L

Pollutants of Concern (2)

0.036 0.015 0.254 0.0920.002 0.090 0.039 0.000 0.211

- Industrial User Contributory Flow is the total industrial wastewater flow of all industrial users that displayed a 2009-2011 average concentration of the respective pollutant above average domestic pollutant concentration plus 3 standard deviations or 1.5 times maximum domestic pollutant concentration if the aforementioned was less than the maximum domestic pollutant concentration.

Ars

enic

, ug/

L

Cad

miu

m, u

g/L

Chr

omiu

m, u

g/L

Cop

per,

ug/L

Lead

, ug/

L

Mer

cury

, ug/

L

Mol

ybde

num

, ug/

L

Nic

kel,

ug/L

Sel

eniu

m, u

g/L

Silv

er, u

g/L

0.000 0.042

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 3-2 IU Contrib Flow December 2012

Average Influent


Average Background


Industrial User Contributory Flow

Domestic Pollutant Load

Maximum Allowable

Headworks Loading

Safety Factor Load

Maximum Allowable Industrial Loading

(2) (3) (4) (5) (6) (7)Pollutant ug/l ug/l MGD lbs/day lbs/day lbs/day lbs/dayArsenic (1) 1.5 1.4* 0.036 0.2 1.1 0.1 0.81Cadmium 0.5 0.3 0.015 0.05 0.6 0.06 0.5Chromium 10.8 5.4 0.254 0.7 224 22 201Copper (1) 73 66* 0.002 8.7 21 2.1 9.8Lead (1) 3.3 3.0* 0.090 0.4 7.0 0.7 5.9Mercury 0.021 0.014 0.039 0.0019 0.0052 0.00052 0.0028Molybdenum 7.0 1.7 0.000 0.2 3.4 0.3 2.8Nickel 12 1.4 0.211 0.2 5.9 0.6 5.1Selenium (8) (9) -- -- -- -- 3.9 0.4 N/ASilver 0.8 0.5 0.042 0.06 1.0 0.1 0.8Zinc (1) 98 88* 0.092 11.5 46 4.6 29Cyanide (1) 0.003 0.0* 0.203 0.0004 9.8 1.0 8.8Phenol (9) 5.5 -- -- -- 574 57 N/AFOG (9) 13208 -- -- -- N/A N/A N/ATPH (9) 359 -- -- -- N/A N/A N/A

Notes: - Average WWTP Influent Flow = 15.8 mgd. (2009-2012)

(6) Safety Factor = MAHL x 0.10. Safety Factor is applied to address data uncertainties.

Table 3-3 Maximum Allowable Industrial Loadings

(4) Industrial User Contributory Flow is the total industrial wastewater flow of all industrial users that displayed a 2009-2011 average concentration of the respective pollutant above average domestic pollutant concentration plus 3 standard deviations or 1.5 times maximum domestic pollutant concentration if the aforementioned was less than the maximum domestic pollutant concentration.

(5) Domestic Pollutant Load = Avg. Dom. Poll. Conc. x (Avg. Infl. Flow - Ind. Contrib. Flow) x 8.34.

(9) The Average Background Pollutant Concentration for Selenium, Phenol, FOG, and TPH is 0, since none of the samples were analyzed for these pollutants.

(3) Average Background (domestic & non-industrial sources) Pollutant Concentration -- based upon collection system sampling data adjusted to remove outliers. If average of sampling data was less than the average plant influent concentration, a value of 90% of the average plant influent concentration was substituted.

(7) MAIL = (MAHL x (1 - Safety Factor)) - Domestic Pollutant Load - Growth Allowance.

(1) As shown in Table 3-2, the Average Domestic Pollutant Concentration based upon 2012 sampling for the following are higher than the respective WWTP Average Influent Pollutant Concentration: arsenic (0.0038 mg/l), copper (0.229 mg/l), lead (0.00634 mg/l), zinc (0.196 mg/l), and cyanide (0.003 mg/l). Accordingly, the background pollutant concentrations for these pollutants were set equal to 90% of the plant raw influent concentration in order to calculate MAIL as noted by "*" next to value.(2) Average Influent Pollutant Concentration is the average of all plant influent concentrations collected from April 16 to May 21, 2012.

(8) The Industrial User Contributory Flow is 0, since no IUs were sampled for these pollutants.

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 3-3 MAIL December 2012

1 2 3 4 5 6 7 8

ug/l ug/l ug/l ug/l ug/l ug/l ug/l ug/l ug/lHighest2nd Highest3rd HighestCity IDHighest2nd Highest3rd HighestCity IDHighest 216,0002nd Highest 24,7903rd Highest 19,710City ID {33329}Highest 880,0002nd Highest 368,0003rd Highest 54,700City ID {33329}Highest2nd Highest3rd HighestCity IDHighest 62nd Highest 53rd HighestCity ID {8524}Highest2nd Highest3rd HighestCity IDHighest 83,000 51802nd Highest 11,3403rd Highest 11,200City ID {33329} {31048}Highest2nd Highest3rd HighestCity IDHighest 1,852 13602nd Highest3rd HighestCity ID {40179} {8516}Highest 103,000 55650 17800 6580 57302nd Highest 48,500 27430 162703rd Highest 16,300 7610City ID {33329} {31048} {31472} {38718} {37288}Highest2nd Highest3rd HighestCity IDHighest2nd Highest3rd HighestCity IDHighest 2,500,000 950000 540000 520000 200000 158000 1200002nd Highest 2,400,000 670000 290000 4100003rd Highest 770,000 630000 230000 410000City ID {37288} {8527} {38777} {37257} {33756} {35521} {31533}Highest2nd Highest3rd HighestCity ID

Notes:

(2) No Industrial Users violated the City's arsenic, cadmium, lead, mercury or cyanide local limit from 2009 - 2011.

(3) No Industrial Users sampled for Molybdenum, Selenium, Phenol or TCLP from 2009-2011.

Zinc, ug/L 4,200

Copper, ug/L 4,500

Lead, ug/L (2) 600

Mercury, ug/L (2) (4)

--

Cyanide, ug/L (2) 1,750

Phenol, ug/L (3) --

(1) All values are the City's current local limit. No current limit exists for Molybdenum, Selenium, Phenol, TPH.

Molybdenum, ug/L (3) --

Nickel, ug/L 4,100

Silver, ug/L 1,200

Selenium, ug/L (3) --

FOG, ug/L 100,000

TPH, ug/L

Table 4-1 - Industrial User Concentrations with Peak Concentration Above Current Local Limit

20

Chromium, ug/L 7,000

Number of Industrial Users with Peak Concentrations Above Current Local Limit or "Threshold Value"

Cadmium, ug/L (2) 1,200

Arsenic, ug/L (2) 2,100

Current Local Limit (1) Pollutant

Industrial User Pollutant

Concentrations

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 4-1_NOV Table December 2012

Electro-plating

Metal Finishing

(1) (2)

Pollutant ug/l ug/l ug/l MGD ug/l ug/l

Arsenic 2,100 -- -- 0.036 2,720 Land Application 2,100

Cadmium 1,200 700 260 0.015 3,840 Land Application 1,200

Chromium 7,000 4,000 1,710 0.254 94,900 Inhib Nitrif 7,000

Copper 4,500 2,700 2,070 0.002 574,000 Inhib Digest 4,500

Lead 600 400 430 0.090 7,830 Land Application 600

Mercury 20 -- -- 0.039 8.64 NPDES 9

Molybdenum -- -- -- -- -- -- --

Nickel 4,100 2,600 2,380 0.211 2,900 Land Application 4,100

Selenium -- -- -- -- -- -- --

Silver 1,200 700 240 0.042 2,290 WLA 1,200

Zinc 4,200 2,600 1,480 0.092 38,300 Inhib Nitrif 4,200

Cyanide 1,750 2,700 650 0.203 5,220 WLA 1,750

Phenol -- -- -- -- -- -- --

FOG 100,000 -- -- -- -- 200,000

TPH -- -- -- -- -- 100,000

Notes:Categorical industrial limits are shown for comparison only. Categorical limits are applied independent of Local Limits.

Table 4-2 Proposed Local Limits

Most Stringent Calculated

Allowable Limit

(1) Electoplating Categorical Industry Limits from 40 CFR 413.

(2) Metal Finishing Categorical Industry Limits from 40 CFR 433.

Current LocalLimit

Proposed Local Limit

Federal Categorical Industry Limits Limiting

FactorContributory

IU Flow

Malcolm Pirnie / ARCADISLocal Limits Tables_rev2012.12.10.xlsx | 4-2_Prop. Local Limit December 2012

Appendix B

EPA Local Limits Spreadsheet


B

APPENDIX B

EPA Local Limits Spreadsheet Calculations

EPA Spreadsheet_Elkhart_rev2012.12.10.xlsx December 2012

TABLE 1Local Limits Determination Based on NPDES Daily Effluent Limits (or WLA PEL)

ENVIRONMENTAL CRITERIA AND PROCESS DATA BASE MAXIMUM LOADING INDUSTRIAL

IU Pollut. POTW Removal NPDES Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Efficiency Daily Limit Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Rpotw) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 49.88 0.00138 15.79 - 0.1820 - - 10Cadmium 0.015 15.82 90.10 0.030 0.00035 15.81 39.98 0.0458 35.95 287.94 10Chromium 0.254 15.82 95.23 2.700 0.00536 15.57 7,462.79 0.6955 6,713.30 3170.42 10Copper 0.002 15.82 94.34 0.075 0.06563 15.82 174.74 8.6579 148.84 8731.94 10Cyanide 0.203 15.82 70.40 0.044 0.0000027 15.62 19.61 0.000352 17.64 10.42 10Lead 0.090 15.82 57.95 0.320 0.00298 15.73 100.42 0.3906 89.61 119.24 10Mercury 0.039 15.82 96.71 0.0000032 0.0000145 15.78 0.01284 0.00190 0.01 0.02993 10Molybdenum 0.000 15.82 29.59 0.00170 15.82 - 0.2249 - - 10Nickel 0.211 15.82 96.26 1.600 0.00139 15.61 5,642.30 0.1813 5,075.82 2885.60 10Selenium 0.000 15.82 34.30 - 15.82 - - - - 10Silver 0.042 15.82 94.92 0.00074 0.00048 15.78 1.92 0.0627 1.67 4.76 10Zinc 0.092 15.82 68.02 0.480 0.08788 15.73 198.02 11.528 166.67 216.71 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Rpotw) Removal efficiency across POTW as percent.(Ccrit) NPDES daily maximum permit limit for a particular pollutant in mg/l. (or Preliminary Effluent Limit from WLA by IDEM.)(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Ccrit * Qpotw 1 - Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS::


TABLE 2 Local Limits Determination Based on NPDES Monthly Effluent Limits (or WLA PEL)


IU Pollut. POTW Removal NPDES Domestic & Commercial Allowable Domestic/ Allowable Local Safety

Pollutant Flow Flow EfficiencyMonthly

Limit Conc. Flow Headworks Commercial Loading Limit Factor(MGD) (MGD) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Rpotw) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 49.88 0.00138 15.79 - 0.182 - - 10Cadmium 0.015 15.82 90.10 0.015 0.000347 15.81 19.99 0.0458 17.95 143.78 10Chromium 0.254 15.82 95.23 1.300 0.00536 15.57 3,593.19 0.696 3,230.30 1525.54 10Copper 0.002 15.82 94.34 0.038 0.06563 15.82 88.53 8.658 70.99 4164.81 10Cyanide 0.203 15.82 70.40 0.022 0.0000027 15.62 9.81 0.000352 8.83 5.22 10Lead 0.090 15.82 57.95 0.160 0.00298 15.73 50.21 0.391 44.79 59.60 10Mercury 0.039 15.82 96.71 0.0000013 0.0000145 15.78 0.0052173 0.00190 0.0028 0.00864 10Molybdenum 0.000 15.82 29.59 0.00170 15.82 - 0.225 - - 10Nickel 0.211 15.82 96.26 0.820 0.00139 15.61 2,891.68 0.181 2,601 1478.56 10Selenium 0.000 15.82 34.30 - 15.82 - - - - 10Silver 0.042 15.82 94.92 0.00037 0.00048 15.78 0.96 0.063 0.8 2.29 10Zinc 0.092 15.82 68.02 0.290 0.08788 15.73 119.64 11.53 96.5 125.43 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Rpotw) Removal efficiency across POTW as percent.(Ccrit) NPDES monthly maximum permit limit for a particular pollutant in mg/l. (or Preliminary Effluent Limit from WLA by IDEM.)(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Ccrit * Qpotw 1 - Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS

::


TABLE 3 Local Limits Determination Based on Activated Sludge Inhibition Level


IU Pollut. POTW RemovalActivated Sludge Domestic & Commercial Allowable Domestic/ Allowable Local Safety

Pollutant Flow Flow Efficiency Inhibition Level

Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Rprim) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 1.00 0.10 0.00138 15.79 13.33 0.1820 11.8 39.4 10Cadmium 0.015 15.82 15.00 5.00 0.00035 15.81 776.16 0.0458 698.5 5593.8 10Chromium 0.254 15.82 41.18 50.00 0.00536 15.57 11,215.50 0.6955 10,093 4766.6 10Copper 0.002 15.82 25.69 1.00 0.06563 15.82 177.57 8.6579 151.2 8867.9 10Cyanide 0.203 15.82 27.00 5.00 0.0000027 15.62 903.75 0.000352 813.4 480.7 10Lead 0.090 15.82 9.30 50.00 0.00298 15.73 7,274.00 0.3906 6,546 8710.7 10Mercury 0.039 15.82 58.44 0.50 0.0000145 15.78 158.75 0.00190 142.9 444.7 10Molybdenum 0.000 15.82 1.02 0.00170 15.82 - 0.2249 - - 10Nickel 0.211 15.82 67.92 2.50 0.00139 15.61 1,028.16 0.1813 925.2 526.0 10Selenium 0.000 15.82 1.00 - 15.82 - - - - 10Silver 0.042 15.82 30.36 0.00048 15.78 - 0.0627 - - 10Zinc 0.092 15.82 13.01 5.00 0.08788 15.73 758.44 11.5277 671.1 872.5 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Rprim) Removal efficiency across across primary treatment as percent.(Ccrit) Activated sludge threshold inhibition level, mg/l.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Ccrit * Qpotw 1 - Rprim US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS

::


TABLE 4 Local Limits Determination Based on Nitrification Inhibition Level


IU Pollut. POTW Removal Nitrification Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Efficiency Inhibition

LevelConc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Rsec) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 1.00 1.50 0.00138 15.79 199.9 0.1820 179.8 599.3 10Cadmium 0.015 15.82 15.00 5.20 0.00035 15.81 807.21 0.0458 726.3 5816.1 10Chromium 0.254 15.82 41.18 1.00 0.00536 15.57 224.31 0.6955 200.9 94.8789 10Copper 0.002 15.82 25.69 0.25 0.06563 15.82 44.39 8.6579 31.3 1836.4 10Cyanide 0.203 15.82 27.00 0.40 0.0000027 15.62 72.30 0.000352 65.1 38.5 10Lead 0.090 15.82 9.30 0.50 0.00298 15.73 72.74 0.3906 65.0 86.5 10Mercury 0.039 15.82 58.44 0.0000145 15.78 - 0.00190 - - 10Molybdenum 0.000 15.82 1.02 0.00170 15.82 - 0.2249 - - 10Nickel 0.211 15.82 67.92 5.00 0.00139 15.61 2,056.32 0.1813 1,854 1053.9 10Selenium 0.000 15.82 1.00 - 15.82 - - - - 10Silver 0.042 15.82 30.36 0.00048 15.78 - 0.0627 - - 10Zinc 0.092 15.82 13.01 0.30 0.08788 15.73 45.51 11.528 29.4 38.3 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Rsec) Removal efficiency across primary treatment and secodary treatment as percent.(Ccrit) Nitrification threshold inhibition level, mg/l.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Ccrit * Qpotw 1 - Rsec US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS

::


TABLE 5 Local Limits Determination Based on USEPA 503 Sludge Regulations


IU Pollut. POTW Sludge Percent Removal 503 Sludge Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Flow Solids Efficiency Criteria Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (MGD) (%) (%) (mg/kg) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Qsldg) (PS) (Rpotw) (Cslcrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 0.01026 15.75 49.88 41 0.00138 15.785 1.107431 0.182 0.815 2.72 10Cadmium 0.0150 15.82 0.01 15.75 90.10 39 0.00035 15.806 0.58 0.046 0.479 3.84 10Chromium 0.254 15.82 0.01 15.75 95.23 0.00536 15.567 - 0.696 - - 10Copper 0.002 15.82 0.01 15.75 94.34 1500 0.06563 15.819 21.42 8.658 10.621 623.10 10Cyanide 0.203 15.82 0.01 15.75 70.40 0.0000027 15.618 - 0.0004 - - 10Lead 0.090 15.82 0.01 15.75 57.95 300 0.00298 15.731 6.97 0.391 5.886 7.83 10Mercury 0.039 15.82 0.01 15.75 96.71 17 0.0000145 15.782 0.23681 0.002 0.211 0.66 10Molybdenum 0.000 15.82 0.01 15.75 29.59 75 0.00170 15.821 3.41 0.225 2.848 - 10Nickel 0.211 15.82 0.01 15.75 96.26 420 0.00139 15.610 5.88 0.181 5.109 2.90 10Selenium 0.000 15.82 0.01 15.75 34.30 100 - 15.821 3.93 - - - 10Silver 0.042 15.82 0.01 15.75 94.92 0.00048 15.779 - 0.063 - - 10Zinc 0.092 15.82 0.01 15.75 68.02 2800 0.08788 15.729 55.46 11.528 38.386 49.91 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Qsldg) Sludge flow to disposal in MGD.(PS) Percent solids of sludge to disposal.(Rpotw) Removal efficiency across POTW as a percent.(Cslcrit) 503 sludge criteria in mg/kg dry sludge.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Cslcrit * (PS/100) * Qsldg Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS::


TABLE 6 Local Limits Determination Based on State Sludge Criteria


IU Pollut. POTW Sludge Percent RemovalState

Sludge Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Flow Solids Efficiency Criteria Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (MGD) (%) (%) (mg/kg) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Qsldg) (PS) (Rpotw) (Cslcrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 0.01026 15.75 49.88 75 0.00138 15.785 2.03 0.182 1.64 5.47 10Cadmium 0.015 15.82 0.01026 15.75 90.10 85 0.00035 15.806 1.27 0.046 1.10 8.79 10Chromium 0.254 15.82 0.01026 15.75 95.23 0.00536 15.567 - 0.696 - - 10Copper 0.002 15.82 0.01026 15.75 94.34 4300 0.06563 15.819 61.41 8.658 46.61 2734.34 10Cyanide 0.203 15.82 0.01026 15.75 70.40 0.0000027 15.618 - 0.00035 - - 10Lead 0.090 15.82 0.01026 15.75 57.95 840 0.00298 15.731 19.53 0.391 17.18 22.87 10Mercury 0.039 15.82 0.01026 15.75 96.71 57 0.0000145 15.782 0.79401 0.00190 0.71 2.22 10Molybdenum 0.000 15.82 0.01026 15.75 29.59 75 0.00170 15.821 3.41 0.225 2.85 - 10Nickel 0.211 15.82 0.01026 15.75 96.26 420 0.00139 15.610 5.88 0.181 5.11 2.90 10Selenium 0.000 15.82 0.01026 15.75 34.30 100 - 15.821 3.93 - - - 10Silver 0.042 15.82 0.01026 15.75 94.92 0.00048 15.779 - 0.063 - - 10Zinc 0.092 15.82 0.01026 15.75 68.02 7500.00 0.08788 15.729 148.55 11.528 122.17 158.85 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Qsldg) Sludge flow to disposal in MGD.(PS) Percent solids of sludge to disposal.(Rpotw) Removal efficiency across POTW as a percent.(Cslcrit) State sludge criteria in mg/kg dry sludge. (Qdom) Domestic/commercial background flow in MGD. (Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Cslcrit * (PS/100) * Qsldg Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS::


TABLE 7Local Limits Determination Based on Chronic Water Quality Standards (for Pollutants with no NPDES Limits or PELs)


IU Pollut. POTW Upstream Upstream Removal Chronic Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Flow Conc. Efficiency WQS Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (MGD) (mg/l) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Qstr) (Cstr) (Rpotw) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 843 49.88 0.148 0.00138 15.785 2113 0.1820 1902 6339 10Cadmium 0.015 15.82 843 0.00 90.10 0.00035 15.806 - 0.0458 - - 10Chromium 0.254 15.82 843 95.23 0.00536 15.567 - 0.6955 - - 10Copper 0.002 15.82 843 0.00 94.34 0.06563 15.819 - 8.6579 - - 10Cyanide 0.203 15.82 843 0.00 70.40 0.0000027 15.618 - 0.0004 - - 10Lead 0.090 15.82 843 0.00 57.95 0.00298 15.731 - 0.3906 - - 10Mercury 0.039 15.82 843 96.71 0.0000145 15.782 - 0.00190 - - 10Molybdenum 0.000 15.82 843 29.59 - 0.00170 15.821 - 0.2249 - - 10Nickel 0.211 15.82 843 0.00 96.26 0.00139 15.610 - 0.1813 - - 10Selenium 0.000 15.82 843 34.30 0.005 - 15.821 54.51 - - - 10Silver 0.042 15.82 843 0.01 94.92 0.00048 15.779 - 0.0627 - - 10Zinc 0.092 15.82 843 68.02 0.08788 15.729 - 11.5277 - - 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Qstr) Receiving stream (upstream) 7Q10 flow in MGD.(Cstr) Receiving stream background level in mg/l.(Rpotw) Removal efficiency across POTW as percent.(Ccrit) State chronic water quality standard for a particular pollutant in mg/l -- for Pollutants with no NPDES Limits or PELs.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * (Ccrit * (Qstr + Qpotw) - (Cstr * Qstr)) 1 - Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS::


TABLE 8Local Limits Determination Based on Acute Water Quality Standards (for Pollutants with no NPDES Limits or PELs)


IU Pollut. POTW Upstream Upstream Removal Acute Domestic & Commercial Allowable Domestic/ Allowable Local SafetyPollutant Flow Flow Flow Conc. Efficiency WQS Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (MGD) (mg/l) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Qstr) (Cstr) (Rpotw) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 621 0.00000 49.9 0.00138 15.785 - 0.1820 - - 10Cadmium 0.015 15.82 621 0.00050 90.1 0.00035 15.806 - 0.0458 - - 10Chromium 0.254 15.82 621 0.00000 95.2 0.00536 15.567 - 0.6955 - - 10Copper 0.002 15.82 621 0.00128 94.3 0.06563 15.819 - 8.6579 - - 10Cyanide 0.203 15.82 621 0.00000 70.4 0.0000027 15.618 - 0.000352 - - 10Lead 0.090 15.82 621 0.00051 58.0 0.00298 15.731 - 0.3906 - - 10Mercury 0.039 15.82 621 0.00000 96.7 0.00001 15.782 - 0.00190 - - 10Molybdenum 0.000 15.82 621 0.00000 29.6 0.00170 15.821 - 0.2249 - - 10Nickel 0.211 15.82 621 0.00092 96.3 0.00139 15.610 - 0.1813 - - 10Selenium 0.000 15.82 621 0.00000 34.3 - 15.821 - - - - 10Silver 0.042 15.82 621 0.00748 94.9 0.00048 15.779 - 0.0627 - - 10Zinc 0.092 15.82 621 0.00000 68.0 0.08788 15.72877 - 11.528 - - 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Qstr) Receiving stream (upstream) 1Q10 flow in MGD.(Cstr) Receiving stream background level in mg/l.(Rpotw) Removal efficiency across POTW as percent.(Ccrit) State acute water quality standard for a particular pollutant in mg/l -- for pollutants with no NPDES Limits or PELs.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * (Ccrit * (Qstr + Qpotw) - (Cstr * Qstr)) 1 - Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS::


TABLE 9 Local Limits Determination Based on Anaerobic Digester Inhibition Level


IU Pollut. POTW Sludge Flow RemovalAnaerobic Digester Domestic & Commercial Allowable Domestic/ Allowable Local Safety

Pollutant Flow Flow to Digester Efficiency Inhibition Level

Conc. Flow Headworks Commercial Loading Limit Factor

(MGD) (MGD) (MGD) (%) (mg/l) (mg/l) (MGD) (lbs/day) (lbs/day) (lbs/day) (mg/l) (%)(Qind) (Qpotw) (Qdig) (Rpotw) (Ccrit) (Cdom) (Qdom) (Lhw) (Ldom) (Lind) (Cind) (SF)

Arsenic 0.036 15.82 0.058 49.9 1.6 0.00138 15.785 1.552 0.1820 1.21 4.04 10Cadmium 0.015 15.82 0.058 90.1 20.0 0.00035 15.806 10.737 0.0458 9.58 76.75 10Chromium 0.254 15.82 0.058 95.2 0.00536 15.567 - 0.6955 - - 10Copper 0.002 15.82 0.058 94.3 40.0 0.06563 15.819 20.510 8.6579 9.79 574.46 10Cyanide 0.203 15.82 0.058 70.4 50.0 0.0000027 15.618 34.355 0.0004 30.96 18.30 10Lead 0.090 15.82 0.058 58.0 340.0 0.00298 15.731 283.79 0.3906 255.21 339.59 10Mercury 0.039 15.82 0.058 96.7 0.00001 15.782 - 0.0019 - - 10Molybdenum 0.000 15.82 0.058 29.6 0.00170 15.821 - 0.2249 - - 10Nickel 0.211 15.82 0.058 96.3 136.0 0.00139 15.610 68.343 0.1813 61.29 34.84 10Selenium 0.000 15.82 0.058 34.3 - 15.821 - - - - 10Silver 0.042 15.82 0.058 94.9 40.0 0.00048 15.779 20.385 0.0627 18.30 52.33 10Zinc 0.092 15.82 0.058 68.0 400.0 0.08787857 15.72877 284.47 11.528 244.07 317.34 10

(Qind) Industrial User total plant discharge flow in Million Gallons per Day (MGD) that contains a particular pollutant.(Qpotw) POTW's average influent flow in MGD.(Qdig) Sludge flow to digester in MGD.(Rpotw) Removal efficiency across POTW as percent.(Ccrit) Anaerobic digester threshold inhibition level in mg/l.(Qdom) Domestic/commercial background flow in MGD.(Cdom) Domestic/commercial background concentration for a particular pollutant in mg/l.(Lhw) Maximum allowable headworks pollutant loading to the POTW in pounds per day (lbs/day).(Ldom) Domestic/commercial background loading to the POTW for a particular pollutant in pounds per day (lbs/day).(Lind) Maximum allowable industrial loading to the POTW in pounds per day.(Cind) Industrial allowable local limit for a given pollutant in mg/l.(SF) Safety factor as a percent. 8.34 Unit conversion factorLhw = 8.34 * Ccrit * Qdig Rpotw US EPA Region 5 Local Limits Spreadsheet: Locallmt.XLS


TABLE 10Summary: Calculated Maximum Allowable Industrial Loadings & Local Limits

Source Table: 1 2 3 4 5 6 7 8 9NPDES NPDES AS Inhib Nitr Inhib 503 State Sludge WQS WQS Dig Inhib

LOCAL LIMITS

Basis for Allowable Industrial

Load

NPDES Daily Effluent Limits

NPDES Monthly Effluent Limits

Activated Sludge

Inhibition Level

Nitrification Inhibition

Level

USEPA 503 Sludge

Regulations (EQ Sludge)

State Sludge Criteria (Ceiling Conc.)

Chronic Water Quality

Standards

Acute Water Quality

Standards

Digester Inhibition

LevelMAIL

Basis for

MAIL

IU Pollut. Flow

(MGD) (Qind)

Local Limit (mg/l) (Cind)

ExistingLocal Limits (mg/l)

Arsenic - - 11.81 179.82 0.8147 1.6413 1902 - 1.21 0.815 503 0.04 2.72 2.1Cadmium 36.0 17.95 698.5 726.3 0.4790 1.0981 - - 9.58 0.479 503 0.01 3.84 1.2Chromium 6,713 3,230 10093.3 200.90 - - - - - 200.9 Nitr Inhib 0.25 94.90 7Copper 148.8 70.99 151.2 31.30 10.6212 46.6088 - - 9.79 9.792 Dig Inhib 0.00 574.00 4.5Cyanide 17.6 8.83 813.4 65.07 - - - - 30.96 8.829 NPDES 0.20 5.22 1.75Lead 89.6 44.79 6546.2 65.04 5.8860 17.1839 - - 255.21 5.886 503 0.09 7.83 0.6Mercury 0.0096 0.0028 142.9 - 0.2112 0.7127 - - - 0.0028 NPDES 0.04 0.0086 0.02Molybdenum - - - - 2.8478 2.8478 - - - 2.848 503 0.00 - -Nickel 5,076 2,601 925.2 1853.82 5.1090 5.1090 - - 61.29 5.109 503 0.21 2.90 4.1Selenium - - - - - - - - - 0.000 Dig Inhib 0.00 - -Silver 1.7 0.80 - - - - - - 18.30 0.801 NPDES 0.04 2.29 1.2Zinc 166.7 96.47 671.1 29.42 38.3860 122.1697 - - 244.07 29.422 Nitr Inhib 0.09 38.30 4.2

ALLOWABLE INDUSTRIAL LOADINGS (lb/d) MAIL

technical justification for industrial user local limits

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