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Recreational WQ Standards and Wastewater Disinfection

Recreational WQ Standards and Wastewater Disinfection. Jim Davenport Monitoring & Assessment Section Water Quality Planning Division Office of Water Texas Commission on Environmental Quality jdavenpo@tceq.state.tx.us tel. 512/239-4585 April 26, 2011.

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Recreational WQ Standards and Wastewater Disinfection

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  1. Recreational WQ Standards and Wastewater Disinfection Jim Davenport Monitoring & Assessment Section Water Quality Planning Division Office of Water Texas Commission on Environmental Quality jdavenpo@tceq.state.tx.us tel. 512/239-4585 April 26, 2011

  2. Characteristics of indicator bacteria Historical linkage of indicators, disinfection Notes on disinfection requirements Notes on dechlorination requirements Development of recreation criteria in U.S. Recreation criteria in Tx WQ Standards (2010) Bacteria limits in discharge permits (EPA, TCEQ) EPA re-evaluation of recreation criteria Table of Contents for This Presentation

  3. Waterborne Diseases/Pathogens BacteriaVirusesProtozoa Shigella Enteric viruses Crypto- Salmonella -(gastroenteritis) sporidium E. coli O157:H7 Adenovirus: Entamoeba Campylobacter -(colds, etc.) Giardia: Cholera Polio Typhoid: Hepatitis A: Photos: 1 & 3 from primewater.com from 2 from OlarMed.com

  4. Indicator Bacteria • E. coli, Fecal coliform, Total coliform, Enterococci, etc. • Surrogate of potential pathogens in water • Ideal characteristics: - Occur at detectable concentrations - Easy to monitor and assess - Well-correlated with actual pathogens - Provide quantifiable risk of disease • Important uses of indicator bacteria: - Indicator of suitability of treated drinking water - Instream criterion for aquatic recreation - Indicator of seafood consumption safety (oysters)

  5. Historical Notes on Pathogens/Indicators • 1854 – John Snow documented cholera outbreak from sewage-contaminated well in London • 1856 – William Budd made a similar demonstration for waterborne typhoid • 1883 – Robert Koch microscopically identified bacteria causing cholera & typhoid • 1891 – E. coli tube tests used to indicate fecal origin of typhoid bacteria in Hudson River, NY From Indicators for Waterborne Pathogens, 2004, National Research Council of the National Academy of Sciences.

  6. Indicators in Early Disinfection Studies Field demonstration of chlorine dosing (“available chlorine”) Side stream from City of Boston trickling filter WWTP From: Earle B. Phelps, 1909, USGS Water Supply Paper 229 Avg. “total bacteria” removal over time at ~ 5 mg/L chlorine: 10 min – 95% 15 min – 99.8% 60 min – 99.9%

  7. Disinfection Requirements in TexasTexas Administrative Code, Chapter 30, Section 309.3(g) • Chlorine requirements for domestic discharges: - Chlorine residual > 0.5 mg/L - Detention time > 20 minutes - Chlorine (mg/L) X Time (minutes) > 20 - Maximum chlorine < 4 mg/L • Exempt: Stabilization ponds > 21 days retention • Alternative disinfection such as UV is allowed: - If supported by engineering report - Additional monitoring or limits as needed

  8. Dechlorination • Advocated by EPA in: Disinfection of wastewater – Task Force Report” MCD-21, EPA-430/9-75-012 1976 • EPA 1984 criteria for total residual chlorine to protect aquatic life: 0.019 mg/L acute: 0.011 mg/L chronic • In 1990, dechlor by two large discharges at Dallas & Fort Worth substantially improved fish in the Trinity River (TPWD, River Studies Report No. 10, 1992) • Dechlor and whole-effluent toxicity testing required in Tx for domestic discharges > 1 MGD since early 1990’s

  9. Dechlorination – Revisions • On 6/30/10, TCEQ approved revisions of the Standards Implementation Procedures • Revised procedures are not in effect until approved by EPA, and EPA’s review is still in progress • The revised procedures require dechlor for domestic discharges > 0.5 MGD (1.0 MGD previously) • For discharges > 0.5 to < 1.0 MGD, dechlor is required only for new and amended permits (not renewals) • EPA comment letter on 12/2/10 indicated that dechlor should apply to discharges < 0.5 MGD

  10. Bacteria Criteria for Recreation • Fed. criteria for fecal coliform published in 1968: - From U.S. Public Health Service epidemiology studies - 200 FC/100 mL as geometric mean - 400 FC/100 mL for single samples (< 10%) - Already in TCEQ WQ Standards in 1967 • New studies & revised EPA criteria in 1986: - E. coli for freshwater: 126/100 mL geo mean - Enterococci for saltwater: 35/100 mL geo mean - Adopted in TCEQ standards in 2000

  11. Revised Recreational Standards (6/30/10) • Previously: Almost all water bodies primary contact • > 300 water bodies not meeting bacteria criteria (2010) • Expand recreational categories • Implement new use-attainability analyses

  12. Uses other than primary contact may be appropriate for some water bodies TCEQ has new recreational UAA procedures Surveys include physical & flow characteristics, + observed evidence of recreation Local input (interviews) important Initiated 90 recreational UAAs Involves major coordination effort and public participation Recreational Use-Attainability

  13. Bacteria Limits in Permits • 1973 – EPA included fecal coliform in performance requirements for domestic wastewater [40 CFR Part 133] • 1976 – EPA deleted these fecal coliform requirements • EPA current reg. requires effluent limits for permits that could “cause or contribute” to WQ impairment – for pollutants of concern [40 CFR Part 122.44] • In 2007, EPA objected to permits to impaired waters – unless bacteria limits included [~24 by Sept 2007] • TCEQ provided documentation for using effluent limits for minimum chlorine residual to regulate disinfection

  14. Effluent Bacteria: Houston TMDL Studies Minor municipal facilities (114 data points) 5 4.5 4 3.5 Log E. coli / 100 ml 3 E. coli (log of #/100 ml) 2.5 Single sample max 2 log (2.6) = 394 / 100 ml 1.5 Geometric mean 1 log (2.1) = 126 / 100 ml 0.5 0 0 5 10 15 20 Residual chlorine (mg/L)

  15. TCEQ Effluent Limits for Bacteria • Adopted 11/4/09; Effective 11/26/09 - 30 TAC §§ 309, 319, 210 • Required for domestic discharge permits - §309.3(h) • Effluent limits = most stringent criteria in WQ standards: - Monthly avg limit = geometric mean criterion in stds - Daily max limit = single sample criterion in stds • Sampling frequency of bacteria effluent limits - §319.9 • Bacteria effluent limits for reclaimed water - §210.33

  16. EPA Review of Existing Recreation Criteria • EPA is re-evaluating bacteria indicators for coastal waters & Great Lakes; for Federal Beach Act of 2000 • Lawsuit settlement (w/ NRDC, NACWA, LA County): - Requires conducting numerous specific studies - Requires publishing criteria by October 15, 2012; as indicated by new studies • Results could amend EPA’s 1986 recreation criteria • Examples of studies: - Additional epidem. studies (e.g., tropical, marine) - Evaluating alternative indicator organisms - Developing rapid tests for indicators (e.g., DNA)

  17. Summary • Bacterial indicators used > 100 years • Current indicators are “imperfect” • TCEQ revised recreation WQ Standards - 6/30/10 • Bacteria effluent limits required as of 11/26/09 • Dechlor for smaller dischargers under EPA review • EPA reviewing recreation criteria – by 10/15/12 • Questions?

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