Local Limits Crash Course Gorman Lau, P.E. CWEA 2016 P3S Conference - PowerPoint PPT Presentation

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