Unregulated, Emerging DBPs Why We Should Understand Them March 26, 2018 Original title of this presentation was “Why Engineers Should Understand Them”. I think it everyone ought to understand them, and at least know what they are. J. Clark Maness, EI Staff Professional, WithersRavenel

PRESENTATION TOPICS What are DBPs? Unregulated, emerging DBPs Alternative Disinfectants Potential Control Options

Why disinfect? Needed to prevent microbial, waterborne diseases. ~ 2.4 million preventable deaths with full access to clean, reliable sanitation and drinking water (Bartram, Cairncross, 2010). Why disinfect? Those who work at water plants know a lot of treatment goes in before disinfection. Need to kill any remaining pathogens in the finished water product, and prevent re-growth in the distribution system. Important step to prevent microbial, waterborne diseases. “KILL THE BUGS” https://infogr.am/poor-people-down-have-clean-water

Disinfection By-Products An unintended consequence: formation of disinfection by-products (DBPs). DBPs formed through oxidation and substitution reactions with organic matter However, as with many good things there are a few side effects. An unintended consequence of chemical disinfection is the formation of many different toxic disinfection-byproducts or DBPs. There are many complex formation routes for each individual DBP. But generally, your disinfectant reacts with natural organic matter that is not removed in the water treatment process to form DBPs. Humic, fluvic acids, etc. http://www.waterhelp.org/index.php/article/introduction_disinfection_byproduct_sampling

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. So, why worry about DBPs? We need to disinfect our water to prevent the spread of waterborne diseases. DBPs are a side effect of a process necessary for preventing acute health risk, but they also pose a serious chronic health risk. Yes, we need to protect the public from acute risks, but we also need reduce the life-time risk of developing cancer and teratogenic effects in fetuses.

Brief History of DBPs and Regulations 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. It’s always surprising to see that we have not been regulating DBPs, or other environmental hazards, for very long. The SDWA was passed in the 1974, allowing the EPA to establish and enforce minimum drinking water standards. Around the same time Rook et al., Bellar et al., and a few other groups discovered THMs, which were subsequently regulated in 1979 http://www.illienglobal.com/international-day-of-happiness-earth-day-model/

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) Many years would pass before more DBPs were regulated until 1998 that the Stage 1 Disinfectants/Disinfection By-Products Rule regulated more DBPs (haloacetic acids, HAAs).

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) Many years would pass before more DBPs were regulated until 1998 that the Stage 1 Disinfectants/Disinfection By-Products Rule regulated more DBPs (haloacetic acids, HAAs).

Effect of alternative disinfectants Positive: The reduction of regulated DBPs Negative: The increased formation of emerging/unregulated DBPs Alternative disinfectants and new multi-disinfectant practices reduce the formation of THMs and HAAs! In chlorinated drinking water, the THMs and HAAs are generally present at the highest levels of the DBPs measured (mid-ppb levels), with chloroform generally being the dominant THM (mean of 23 mg/L in the ICR, with some samples above 100 mg/L) and dichloroacetic acid and trichloroacetic acid being the dominant HAAs (mean of 11 and 10 mg/L in the ICR, respectively). The sum of the four regulated THMs (THM4) are generally present at levels higher than the sum of the five regulated HAAs (HAA5); however, the sum of the nine total chloro-bromo-HAAs (HAA9, i.e., the five regulated plus four unregulated HAAs) can be present at levels comparable to THM4. Chloramination and ozonation generally produce much lower levels of THMs and HAAs relative to chlorine, although ozonation can produce ppb levels of bromoform and dibromoacetic acid in high-bromide source waters. Chlorine dioxide can also produce HAAs (mean of 23 mg/L in the ICR for the five regulated HAAs). With the U.S. Stage 1 and Stage 2 D/DBP regulations, the current mean levels will likely be lower in the United States than when the ICR data were collected (1997– 1998).

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 In the 30 years since the THMs were identified as DBPs in drinking water, significant research efforts have been directed toward increasing our understanding of DBP formation, occurrence, and health effects [2,8–17]. Although more than 600 DBPs have been reported in the literature [2,18], only a small number has been assessed either in quantitative occurrence or health-effects studies.

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

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. Why care, they’re not regulated. The decisions we make directly or indirectly impact public health.

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.

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)

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)

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

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)

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

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

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

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

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