Water Resources Research Act Program

Details for Project ID 2020WV044B

Drinking Water Treatment Methods to Reduce THM

Institute: West Virginia
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $19,914 Total Non-Federal Funds: $41,033

Principal Investigators: LianShin Lin

Abstract: Trihalomethanes, a family of halogenated disinfection byproducts is ubiquitously present in finished drinking water. This is a great concern for the public health since daily intake of those compounds can create toxicity and cancer in humans. According to USEPA’s Disinfectants/Disinfection Byproducts Rule (D/DBPR), the regulatory standard of the total Trihalomethanes (TTHMs) is 80 μg/L, and water treatment plant operators are required to closely monitor TTHMs in the finished water on quarterly basis. The Disinfectants/Disinfection Byproducts Rule (D/DBPR) also requires water systems that treat surface water to remove a percentage of the total organic carbon (TOC) in the source water influent based on concentration and alkalinity. Although TOC has been identified as a precursor for the TTHMs, knowledge gaps still exist in how water treatment plant specific factors (e.g., intake water quality, seasonal variation, contact time, and treatment units) affect TTHM formation. Continuing with sample collection of water treatment plants in southwestern Pennsylvania and adding in plants in West Virginia, the objectives of this additional year of study are to: 1) further develop statistical models for predicting TTHM levels using source water quality data, and 2) further examine the effects of water treatment and distribution on TTHMs formation. Given the adverse effect of the THM, water plant operators are required to monitor the THM level in the finished water through the distribution network. This study aims to aid the operators reduce trihalomethane occurrences and levels in small treatment plant by investigating linking the precursor levels and factors contributing to THM formation. To perform this study, monthly samples are taken form three water treatment authorities and five points within distribution network starting from September 2018 till May 2019 at Southwestern Pennsylvania. The results showed that the concentration of TOC in the source water highly controlled the formation of THM in finished water. The linear regression of THM and total organic carbon (TOC) gave better fit for individual treatment plants indicating influence of different operation techniques. The highest TOC occurred during September and October which also caused THM violation in all the sampled distribution points. As the bromide level was lower (mostly undetected), the chlorinated THM dominated in the finished water. Using the chloroform concentration alone, the total concentration of THM was checked applying linear regression. Moreover, a multiple linear regression model was developed to predict THM in the finished water using chloride, TOC and temperature values. Lastly, the secondary data obtained from Charleroi Water Authority was utilized to show the effectiveness of pre-sedimentation tank for controlling elevated THM formatted. Furthering the study with an additional year of data collection as well as an additional site in West Virginia will take our research one step further towards having a positive impact on water treatment operations, ultimately improving our drinking water quality.