The Nuts & Bolts of TBLL Development Duyen Tran OMI, Inc.

The “Bible” EPA Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the Pretreatment Program EPA 833-R-04-002A July 2004

7-steps process Preliminary Data Collection Identify Pollutants of Concern Sampling Plan Data Collection & Evaluation Calculation Technical Review TBLL Submission

Preliminary Data Collection Receiving stream designation Water Quality Standards for the designated receiving stream Most recent priority pollutant scans on plant influent (include analyses of additional pollutants specified in State Water Quality Standards)

Identify Pollutants of Concern (POC) Pollutants with concentration greater than 0.1 mg/l in the influent scan, adjust for inflow/infiltration if the plant has I/I problem Pollutants associated with historical plant problems Fifteen EPA’s POCs: Cd, Cr, Cu, Pb, Ni, Zn, As, CN, Ag, Hg, Mo, Se, BOD, TSS, Ammonia

Sampling Plan Review historical data on pollutants of concern for: influent, effluent, primary effluent, sludge, industrial effluent, inhibition data, background (domestic & commercial) Reject data that is anomaly Reject data that does not meet laboratory QA/QC or required MDLs

Sampling Plan (cont’d) In lieu of at least 6 months of historical data, collect at least 6 consecutive days of samples for influent, effluent, and background Consider plant retention time when collecting new influent and effluent data In all cases, obtain the most representative collection of data for TBLL calculation

Data Collection & Evaluation NPDES Permit State WQS 503 Sludge Criteria Receiving Stream, 7Q10 or 7Q2 Plant diagram and description of plant processes POTW Flow Digester Flow Industrial Flows Background Flow (Domestic + Commerical)

Data Collection & Evaluation Review analytical data for: Chain of custody Laboratory QA/QC MDLs Reject data that appears to be anomaly or does not meet the above criteria Document the data evaluation process

Calculation Plant Removal Efficiency, % Allowable Headworks Loadings Background (Domestic) Loadings Derive Maximum Allowable Headworks Loadings (MAHL) Maximum Allowable Industrial Loadings (MAIL)

Allowable Headworks Loadings (AHL) Calculate AHL for: Water Quality Standards NPDES Permit Process Inhibition/Operational Problems Sludge Disposal Criteria

Maximum Allowable Industrial Loadings, MAIL MAIL = MAHL - (Background + Safety Factor)

Allocation Uniform Concentration Industrial Contributory Flow Mass Proportion Method Selected Industrial Reduction Method

Applications of Local Limits Industrial Discharge Permit Limits Calculation New Discharge Permit Consideration Plant Loadings Assessment

Technical Review Technical Support Staff City Engineers City Council

TBLL Submission Use State guidelines and checklist on program modification and submittal Prepare a professional certification Incorporate the new technically based local limits to the sewer use ordinance (SUO) Submit three copies of the TBLL study and revised SUO to the State

Resources EPA Guidance Manual on the Development and Implementation of Local Discharge Limitations Under the Pretreatment Program EPA Supplemental Manual EPA Region VI TBLL Guidelines

Duyen Tran, Project Manager OMI, Inc. City of Fayetteville WWTP 1400 N. Fox Hunter Road Fayetteville, AR 72701 duyen.tran@omiinc.com (479) 443-3292