Water Resources Research Act Program

Details for Project ID 2018WV238B

3RQ 05 - Drinking Water Treatment Methods to Reduce THM

Institute: West Virginia
Year Established: 2018 Start Date: 2018-03-01 End Date: 2019-02-28
Total Federal Funds: $19,985 Total Non-Federal Funds: $48,714

Principal Investigators: Lian-Shin Lin, Paul Ziemkiewicz, Melissa ONeal

Abstract: Problem: While drinking water disinfectants are effective in controlling many microorganisms, they react with natural organic and inorganic matter in source water and distribution systems to form Disinfection By-Products (DBPs) such as the Trihalomethanes (THM). Knowledge gaps concerning the formation of trihalomethanes, particularly their relationship to source water halogen concentrations are evident in current research studies, especially for small water treatment facilities. Supplementary studies are warranted to address these gaps; furthermore, this knowledge could then be made applicable for treatment plant operators when managing their respective water treatment systems. Thus, improving the water quality and safety of the consumers. Results from toxicology studies show that several DBPs (e.g. bromodichloromethane, bromoform, chloroform) to be carcinogenic in laboratory animals. Several epidemiology studies have suggested a weak association between certain cancers (e.g. bladder) or reproductive and developmental effects, and the exposure to chlorinated surface water (EPA, 2011). In 2002, the Disinfectants/Disinfection Byproducts (D/DBP) Rule affected surface water treatment plants serving at least 10,000 people. Small plants started monitoring in the first quarter of 2004. In addition to monitoring for Total Organic Carbon (TOC), the water authorities are also required to monitor for total THM (THM) along with haloacetic acids (HAA5). Treatment plant operators often encounter THM levels above the 80 g/L primary drinking water standard; yet, workable guidelines for reducing THM levels are not available. Methods: The 3 Rivers QUEST (3RQ) program at West Virginia Water Research Institute (WVWRI) will collect additional water quality samples to analyze the relationship of bromide and chloride levels to THM formation. A thorough literature review will be conducted to examine related studies. The relationship between intake bromide levels and THM in finished water is not completely clear, high bromide levels at the water authority’s intake could increase the risk of exceeding THM limits 3RQ recently conducted a two-year study concerning the formation of THMs in various water treatment plants in Southwestern Pennsylvania. The focus of this study was the relationship of bromide levels to that of THM formation as a function of a range of factors such as temperature. These preliminary results suggested that elevated THM levels occurred during low flow, late summer/fall conditions when river temperatures and microbial populations were at a maximum. Thus, excessive chlorination was more important in determining THM levels than intake water halogen concentrations, at least within the observed range. Discussions with drinking water utilities supported this hypothesis. , THMTHM However, no exceedingly high bromide levels were found in the intake samples during the study. Furthermore, the data showed no direct correlation between either bromide or chloride levels at the river intakes and any of the four THM species. About 90% of the THMs were either purely or dominantly chlorinated forms, suggesting that chlorination alone might be the dominant factor in raising THM levels during low river flow periods. In this study, we will supplement our earlier seasonal sampling at several utilities to test whether the earlier observations are valid and develop appropriate risk mitigation guidance for utility operators. Objectives: This research study will identify knowledge gaps concerning the formation of THMs in public water supplies and highlight areas where further research on the formation of THM’s is needed. This knowledge could then have real world applications if used by water treatment plant operators when managing their respective facilities. The goal is to increase the understanding of THM formation, convey that knowledge to water treatment plant operators, and in-turn have them apply that knowledge for the benefit of public health by establishing water treatment methods to reduce the formation of THM. A peer reviewed article detailing the findings will be published; in addition, findings will also be presented at professional meetings and conferences.