Local Limits Crash Course Gorman Lau, P.E. CWEA 2016 P3S Conference February 29, 2016
Presentation Outline Background Local limit evaluations Local limits update/development Local limits implementation Local limits troubleshooting Summary and Q/A 2
Why have a Pretreatment Program? Protect POTW from interference or upset of treatment operations Prevent pass-through of pollutants Prevent harm to POTW infrastructure Protect biosolids quality Protect public health and safety 3
Who must have a Pretreatment Program? Defined in 40 CFR Part 403 POTWs with design flow > 5 mgd POTWs with design flow ≤ 5 mgd Directed by regulatory agency 4
What is required for Pretreatment Program? Pretreatment Program Documents Administrative procedures Sewer Use Ordinance (SUO)/Legal Authority General and specific prohibitions Categorical limits Local limits Enforcement Response Plan (ERP) Wastewater discharge permits/control mechanism Program approved by Regional Water Board 5
What are general and specific prohibitions? Narrative discharge limits General prohibitions – no discharge of pollutants causing pass-through or interference Specific prohibitions – characteristics of wastewater that cannot be discharged into collection system (e.g., pH, temperature, fire/explosive hazards) Required by 40 CFR Part 403.5 Example language in USEPA Model Sewer Use Ordinance 6
What is a categorical limit? Effluent limits for industrial processes Regulates specific discharges from 35 industries Concentration- or mass-based Applied at end-of-process typically at end of pretreatment system Required by 40 CFR Parts 405-471 7
What is a local limit? Technically-based effluent limit for industrial (or other regulated) users Concentration- or mass-based Applied at end-of-pipe 8
Pollutant Pie Background (non- regulated) Regulated Growth Hauled Waste Safety Factor 9
Categorical vs. local limits Non- Regulated regulated process process wastewater wastewater Discharge to Categorical lim its collection system Local lim its 10
Categorical vs. local limits Regulated process wastewater #2 Regulated Non- process regulated wastewater process #1 wastewater Discharge to Categorical collection lim its system Local lim its 11
Categorical vs. local limits Regulated process wastewater Discharge to collection system Categorical & Local lim its 12
What is a local limit? Technically-based effluent limit for industrial (or other regulated) users Concentration- or mass-based Applied at end-of-pipe Required by 40 CFR Part 403.5 Guidance documents Local Limits Development Guidance (July 2004) Local Limits Guidance (December 1987) 13
Why do you need local limits? Protect POTW Infrastructure Treatment process integrity Final effluent quality (meet discharge requirements) Biosolids quality Protect human health and safety Protect the environment 14
Applicability of restrictions Categorical Significant Other Industrial Restriction Industrial User Industrial User Users General and specific X X X prohibitions Categorical limits X Local limits X X * * Local limits may apply 15
Life cycle of local limits Update/Develop Local Limits Evaluate Local Implement Local Limits Limits 16
Update/Develop Local Limits Evaluate Local Implement Local Limits Limits 17
Why conduct a local limits evaluation? It may be required: Pretreatment compliance inspection (PCI) Pretreatment compliance audit (PCA) Discharge permit Things change over time Local Limits Guidance recommends periodic evaluations 18
What things change? Treatment plant upgrades Treatment process modifications Wastewater/biosolids quality Wastewater discharge effluent limits Biosolids handling/disposal Regulated user base Water supply 19
What do you want to get out of a local limits evaluation? Verify existing pollutants of concern Identify new pollutants of concern Assess existing data quantity and quality Gain an understanding of the pollutant loadings to the treatment plant Magnitude Temporal variations/trends Determine next steps, if necessary 20
How do you conduct a local limits evaluation? Identify pollutants of concern (POCs) Compare recent influent pollutant loads with the Maximum Allowable Headworks Loading (MAHL) for each pollutant Conduct compliance analysis Document the evaluation 21
Where do you find POCs? Existing local limits 2004 Local Limits Guidance 15 national POCs Appendix C: Pollutants Regulated by Categorical Standards Appendix G: Literature Inhibition Values Discharge permits Biosolids limits Treatment design capacities 22
How do you compare influent loads to MAHLs? Local Limits Guidance thresholds Average influent load > 60 percent of MAHL Maximum influent load > 80 percent of MAHL Monthly average influent load > 80 percent of design capacity for BOD, TSS, or ammonia Other thresholds If any threshold exceeded, re-evaluate local limit If threshold not exceeded, is a local limit necessary? 23
What is a compliance analysis? Is treatment plant meeting discharge limitations? Is treatment plant meeting biosolids disposal limits? Have there been treatment plant upsets? Are regulated dischargers complying with local limits? Do they need more flexibility? 24
What are the potential outcomes of a local limits evaluation? Confirm existing local limits are adequate Propose removal an unnecessary existing local limit Focus next steps/future effort Identify data gaps and additional sampling that may be needed to complete the evaluation or update/develop local limits Consider implementing ongoing monitoring program Document results of evaluation 25
Minimum Recommended Sampling Frequency (Ongoing) 10-50 Parameter Location < 5 MGD 5-10 MGD >50 MGD MGD Pollutants with Influent, Every local limit Effluent, Quarterly Quarterly Quarterly other Biosolids month Pollutants with Influent, Semi- Semi- MAHLs, but no Effluent, Annually Quarterly annually annually local limit Biosolids Organic priority Semi- Influent Annually Annually Annually pollutants annually TCLP pollutants Biosolids Annually Annually Annually Annually Biosolids % Once Every Semi- solids and Biosolids every 4 Quarterly other annually specific gravity months month Source: 2004 Local Limits Guidance
Update/Develop Local Limits Evaluate Local Implement Local Limits Limits 27
How do you update/develop local limits? Identify applicable operational/environmental restrictions Review and collect relevant data Conduct screening Conduct headworks loading analysis Calculate removal efficiencies Calculate MAHLs Calculate maximum allowable industrial loadings (MAILs) local limits 28
What operational/environmental restrictions to consider? Treatment plant design capacities Treatment process inhibition levels Activated sludge Nitrification Trickling filters Anaerobic digestion Effluent limits Biosolids limits Air quality standards 29
What is the secret to local limits update/development? × × 8 . 34 C Q = NPDES EFF AHL NPDES R POTW × × 8 . 34 C Q = AS PE AHL AS R PE × × × × 8 . 34 C PS Q G = sldg sldg sldg AHL sldg R POTW HIGH QUALITY SITE-SPECIFIC DATA!!! 30
Is it really that important? USEPA Plant A Plant B Plant C Plant D Pollutant (2004) (2012) (2013) (2014) (2015) Arsenic 11-78% 41% 7% 35% 47% Cadmium 25-99% 90% 78% 92% 94% Chromium 25-97% 86% 74% 89% 84% Copper 2-99% 85% 54% 91% 92% Lead 1-92% 95% 76% 95% 95% Mercury 1-95% 99% 74% 97% 99% Nickel 2-99% 19% 14% 61% 53% Silver 17-95% 95% 62% 96% 98% Zinc 23-99% 88% 31% 82% 95% Cyanide 3-99% -14% -170% -640% 58% Activated sludge treatment plant average removal efficiencies 31
X Biosolids Disposal Processing Non- Regulated regulated dischargers X dischargers X X X X X Primary Secondary Tertiary Headworks Treatment Treatment Treatment Disinfection X Effluent X = Data locations 32
Why do you need a Sampling and Analysis Plan (SAP)? Goal: Produce high quality scientifically- defensible data that adequately characterizes the site-specific conditions Uncontrollable loads Treatment plant removal efficiencies Biosolids quality Outline all information related to sampling and analysis activities 33
What goes into a SAP? Sampling locations Pollutants of concern Sampling frequency Types of samples Analytical requirements Quality assurance/quality control (QA/QC) procedures 34
Where to potentially sample? Collection system POTW influent Between treatment processes Final effluent Anaerobic digester Biosolids to disposal 35
Recommend
More recommend
