Occurrence and modeling of THMS and HAA formation in drinking water

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Trihalomethanes (THMs) and haloacetic acids (HAAs) are two of the largest classes of disinfection by-products (DBPs) during chlorination in drinking waters. In this dissertation, the formation of THMs and HAAs in drinking water plants in Missouri was investigated to further understand their occurrence and predict their formation. Firstly, the occurrence of TTHM and HAA5 in Missouri public water supplies was investigated by analyzing the database from Missouri Department of Natural Resources (MoDNR) from 1999 to 2006. The results indicated that many plants exceeded the current standards and the formation of TTHM and HAA5 had a seasonal trend. Secondly, based on the data analysis of MoDNR database, eight Missouri water samples were collected and investigated from Harrison, Jamesport, Higginsville, Lexington, Adrian, Creighton, Boonville and Columbia in Missouri. Water samples were fractionated in four fractions: raw water, hydrophobic, transphilic and hydrophilic extracts, for the chlorination to test the formation of DBPs. Finally, DBPs formation in Boonville Water Treatment Plant in Missouri was investigated because of their high concentration of THMs in the drinking water. A series of experiments were designed and conducted to discover the reasons for high concentration of THMs. The data were modeled to predict the formation of THMs, which was examined with experimental data and fit with the accuracy higher than 80%.