Relationships between trihalomethane formation potential and surrogate parameters for dissolved organic matter in reservoir water and treated wastewater in Thailand

Abstract

Relationships between trihalomethane formation potential (THMFP) and dissolved organic matter (DOM) surrogate parameters including dissolved organic carbon (DOC), ultraviolet adsorption at wavelength 254 nm (UV-254) and specific ultraviolet adsorption (SUVA) were investigated from six water sources in Thailand. Five raw water supply sources were Mae-Hia Reservoir, Aung-Keaw Reservoir, Mae-Kuang Reservoir in Chaing Mai province, the Bhumibol Dam Reservoir in Tak Province, and the Northern-Region Industrial Estate Reservoir in Lamphun province, Thailand. One treated wastewater was effluent water from the central wastewater treatment plant of the Northern-Region Industrial Estate. The coagulation process was utilized to remove DOM from all water samples. In the case of raw water, coagulated water, hydrophobic organic fraction and hydrophilic organic fraction of reservoir water, moderate correlations were obtained from relationships between THMFP and DOC, (R2 of 0.83) and between THMFP and UV-254 (R2 of 0.77). Correlations were significant at the 0.01 level. A poor correlation was obtained from relationship between THMFP and SUVA (R2 of 0.34). The fitting equation for predicting THMFP in reservoir water and its coagulated water could be expressed as follows: THMFP ( g/L) = 73.67DOC (mg/L) + 86.8. In case of treated wastewater and its coagulated water, moderate correlation (R2 of 0.84), good correlation (R2 = 0.96) and moderate correlation (R2 of 0.81) were observed from relationships between THMFP and DOC, THMFP and UV-254, and between THMFP and SUVA, respectively. Correlations were significant at the 0.01 level. The appropriate equation for predicting THMFP in treated wastewater and its coagulated water could be expressed as follows: THMFP ( g/L) = 813.3DOC (mg/L) + 310. In conclusion, DOC and UV-254, therefore, moderately correlated with THMFP in both reservoir water and treated wastewater. SUVA moderately correlated with THMFP in treated wastewater; however, it did not relate to THMFP in reservoir water in Thailand.