Unregulated, Emerging DBPs

1. Unregulated, Emerging DBPs Why We Should Understand Them March 26, 2018 J. Clark Maness, EI Staff Professional, WithersRavenel

2. PRESENTATION TOPICS

3. Why disinfect? https://infogr.am/poor-people-down-have-clean-water Needed to prevent microbial, waterborne diseases. ~ 2.4 million preventable deaths with full access to clean, reliable sanitation and drinking water (Bartram, Cairncross, 2010).

4. Disinfection By-Products http://www.waterhelp.org/index.php/article/introduction_disinfection_byproduct_sampling An unintended consequence: formation of disinfection by-products (DBPs). DBPs formed through oxidation and substitution reactions with organic matter

5. Importance of DBP Control • Why DBP control? • Carcinogenic • Mutagenic • Teratogenic • Drinking water systems will continue to disinfect the water we drink and we’re forced to balance risks.

6. Brief History of DBPs and Regulations http://www.illienglobal.com/international-day-of-happiness-earth-day-model/ The Safe Drinking Water Act (SDWA) passed in 1974. Environmental Protection Agency (USEPA) to establish and enforce drinking water standards. Around the same time, trihalomethanes (THMs) were discovered, and subsequently regulated by the USEPA in 1979.

7. Brief History of DBPs and Regulations • 1998: Stage 1 Disinfectants/Disinfection By-Products Rule (DBPR) regulated more DBPs and reduced acceptable THM levels • 2006: Stage 2 DBPR implemented stricter monitoring requirements in distribution systems. • Today, still only 11 regulated DBPs. • 4 Trihalomethanes (THM4) • 5 Haloacetic Acids (HAA5)…but there are nine total HAAs (HAA9) • Bromate and chlorite (oxyhalides)

8. Brief History of DBPs and Regulations • Many utilities struggled with Stage 1 and 2 DBPR regulations. • Popular way to comply was to switch to an alternative disinfectant and/or use multiple disinfectants. • Alternative disinfectants • Chloramines (mono-, di-, & tri-) • Ozone (O3) • Chlorine Dioxide (ClO2) • Ultra Violet (UV)

9. Effect of alternative disinfectants • Positive: The reduction of regulated DBPs • Negative: The increased formation of emerging/unregulated DBPs

10. Emerging/Unregulated DBPs • Presently identified emerging DBP classes include: • Halonitromethanes (HNMs) • Halofuranones • Haloamides (HAMs) • Haloacetonitrile (HANs) • Tribromopyrrole • Haloacetaldehydes (HALs) • Iodo-Haloacetic Acids (I-HAAs) • Iodo-Trihalomethanes (I-THMs) • Nitrosamines • More than 600 identified DBPs

11. What is an emerging DBP? • Have at least a moderate occurrence level in public drinking water systems (sub- to low µg/L) • Known or suspected to cause adverse toxicological effects in humans • Currently not regulated by the USEPA or individual state authority

12. Why care? • It’s our duty to care about the health of the public. • With GenX, C8, and etc. our customers are more well-informed than ever. • Regulations will likely get stricter in the future.

13. Examples • Ozone  Bromate Formation • Reduces or removes formation of THMs and HAAs • However, leads to elevated levels of bromate (known carcinogen in lab animals) • Big issue if elevated levels of bromide present.

14. Examples • Chloramines  NDMA Formation • Reduces formation of THMs and HAAs • However, leads to elevated levels of Nitrosodimethlyamine (NDMA) (probable human carcinogen) • Big issue if elevated levels of tertiary amines present (think biopolymers and treatment polymers)

15. Examples • Chlorine Dioxide  Chlorite Formation • Reduces formation of THMs and HAAs • However, leads to elevated levels of Chlorite (regulated DBP) • Chlorite causes anemia; nervous system damage in infants and young children)

16. Control of Emerging DBP Formation • Four (4) general options • DBP precursor material removal • Preformed DBP and precursor removal • DBP removal post disinfection • Distribution System Control

17. Control of Emerging DBP Formation • DBP precursor material removal • Activated carbon filtration • Granular activated carbon (GAC) or powdered activated carbon (PAC) • May lead to formation of more brominated/iodinated DBPs • Membrane filtration • Ultrafiltration, nanofiltration, and reverse osmosis • Expensive • Enhanced Coagulation and Sedimentation (increased TOC removal) • Increased coagulant costs • Capital cost for improved settling equipment (example: settling plates)

18. Control of Emerging DBP Formation • Preformed DBP and DBP precursor removal • Add disinfectant at different points in treatment process to preform DBPs • DBPs then removed during processes highlighted earlier • Activated carbon filtration • Granular activated carbon (GAC) or powdered activated carbon (PAC) • May actually • Membrane filtration • Ultrafiltration, nanofiltration, and reverse osmosis • Expensive

19. Control of Emerging DBP Formation • DBP Removal Post-Disinfection • Aeration (good for THM and other volatile DBP removal)

20. Control of Emerging DBP Formation • Distribution System Control • Tank aeration • Change chlorination points in system • Tank Recirculation

21. Great Resources on Emerging DBPs Richardson, S., Plewa, M., Wagner, E., Schoeny, R., & Demarini, D. (2007). Occurrence,genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. Krasner, S. W., Weinberg, H. S., Richardson, S. D., Pastor, S. J., Chinn, R., Sclimenti, M. J., Thruston, A. D. (2006). Occurrence of a New Generation of Disinfection Byproducts †. Environmental Science & Technology, 40(23), 7175-7185. doi:10.1021/es060353j

22. Great Resources on Emerging DBPs Richardson, S., Plewa, M., Wagner, E., Schoeny, R., & Demarini, D. (2007). Occurrence,genotoxicity, and carcinogenicity of regulated and emerging disinfection by-products in drinking water: A review and roadmap for research. Mutation Research/Reviews in Mutation Research, 636(1-3), 178-242. doi:10.1016/j.mrrev.2007.09.001