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Solar photolysis of soluble microbial products as precursors of disinfection by-products in surface water

Wu, Jie, Ye, Jian, Peng, Huanlong, Wu, Meirou, Shi, Weiwei, Liang, Yongmei, Liu, Wei
Chemosphere 2018 v.201 pp. 66-76
activated sludge, byproducts, chloral hydrate, chlorine, chloropicrin, disinfection, dissolved organic matter, drinking water, irradiation, laboratory experimentation, lighting, municipal wastewater, photolysis, risk, river deltas, rivers, solar radiation, surface water, water treatment
In the Pearl River Delta area, the upstream municipal wastewater is commonly discharged into rivers which are a pivotal source of downstream drinking water. Solar irradiation transforms some of the dissolved organic matter discharged from the wastewater, also affecting the formation of disinfection by-products in subsequent drinking water treatment plants. The effect of simulated solar radiation on soluble microbial products extracted from activated sludge was documented in laboratory experiments. Irradiation was found to degrade macromolecules in the effluent, yielding smaller, more reactive intermediate species which reacted with chlorine or chloramine to form higher levels of noxious disinfection by-products. The soluble microbial products were found to be more active in formation of disinfection by-products regard than naturally-occurring organic matter. The results show that solar irradiation induced the formation of more trihalomethane (THMs), chloral hydrate (CH) and trichloronitromethane (TCNM), causing greater health risks for downstream drinking water.