Duyen Tran

1
The Nuts Bolts of TBLL Development

• Duyen Tran
• OMI, Inc.

2
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

3
7-steps process

• Preliminary Data Collection
• Identify Pollutants of Concern
• Sampling Plan
• Data Collection Evaluation
• Calculation
• Technical Review
• TBLL Submission

4
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)

5
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 EPAs POCs Cd, Cr, Cu, Pb, Ni, Zn, As,
  CN, Ag, Hg, Mo, Se, BOD, TSS, Ammonia

6
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

7
Sampling Plan (contd)

• 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

8
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)

9
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

10
Calculation

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

11
Allowable Headworks Loadings (AHL)

• Calculate AHL for
• Water Quality Standards
• NPDES Permit
• Process Inhibition/Operational Problems
• Sludge Disposal Criteria

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Maximum Allowable Industrial Loadings, MAIL

• MAIL MAHL - (Background Safety Factor)

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15
Allocation

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

16
Applications of Local Limits

• Industrial Discharge Permit Limits Calculation
• New Discharge Permit Consideration
• Plant Loadings Assessment

17
Technical Review

• Technical Support Staff
• City Engineers
• City Council

18
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

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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

21

• Duyen Tran, Project Manager
• OMI, Inc.
• City of Fayetteville WWTP
• 1400 N. Fox Hunter Road
• Fayetteville, AR 72701
• duyen.tran_at_omiinc.com
• [phone]