Recreational WQ Standards and Recreational WQ Standards and Wastewater DisinfectionWastewater 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

Table of Contents for This Presentation

▸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

Waterborne Diseases/Pathogens

Bacteria Viruses Protozoa

Shigella Enteric viruses Crypto-Salmonella -(gastroenteritis) sporidiumE. coli O157:H7 Adenovirus: EntamoebaCampylobacter -(colds, etc.) Giardia:Cholera PolioTyphoid: Hepatitis A:

Photos: 1 & 3 from primewater.com from 2 from OlarMed.com

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)

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.

Indicators in Early Disinfection Studies

Field demonstration of chlorine dosing (“available chlorine”)Side stream from City of Boston trickling filter WWTPFrom: 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%

Initial chlorine mg/L E. coli per mL

Monthly mean Before ~ 2 hours % removal2.5 mg/L (Nov, N=3) 41,500 720 98.36.1 mg/L (Apr, N=4) 135,300 8 99.9

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

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

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

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

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

Recreation Uses Indicator Bacteria (#/100 ml)Geometric Mean Criteria

Single-sample Max Criteria in BracketsE. coli (FW) Enterococci (SW)

Previous Standards: Contact recreation 126 [394] 35 [89] Noncontact rec. 605 168Revised Standards:(Adopted 6/30/2010)

Primary contact 126 [399] 35 [104] Secondary contact 1

630 175

Secondary contact 2

1030 --

Noncontact rec.

2060 350

Recreational Use-Attainability

▸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 effortand public participation

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

Effluent Bacteria: Houston TMDL StudiesEffluent Bacteria: Houston TMDL Studies

Minor municipal facilities(114 data points)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 5 10 15 20

Residual chlorine (mg/L)

E. c

oli

(lo

g o

f #

/10

0 m

l)

Log E. coli / 100 ml

Single sample max log (2.6) = 394 / 100 ml

Geometric mean log (2.1) = 126 / 100 ml

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

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)

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?