抄録
In order to obtain a better understanding of the situation on trihalomethane precursors and halogenated organics in a watershed, it is essential to evaluate the trihalomethane precursors loads caused by the discharge of secondary effluents into the receiving water as well as the natural loads originated from humic substances.
For each unit process of a municipal wastewater treatment, the daily variations of formation potential of halogenated organics, such as THM (Trihalomethane), TPTHM (Total Potential THM) and TOX (Total Organic Halide), and those of the concentrations of volatile halogenated organics were investigated. Volatile halogenated organics are reduced to 14% of the initial concentration by activated sludge treatment and precursors of halogenated organics are reduced to 23% of TOX, 46% of TPTHM and 72% of THM. Formation potential of THM, TPTHM, and TOX formed from the chlorination of the secondary effluent are 25.5±4.1(μg·mg C-1), 54.1±10.0(μg·mg C-1) and 166+ 33(μg·mg C-1), respectively. Although TOX formation potential of the secondary effluent is 9% lower than that of the sewage, THM formation potential of the secondary effluent is 2.6 times as much as that of the sewage, and TPTHM formation potential is 1.6 times as greater as that of the sewage. However, there is no significant difference between these values and those obtained from the surface water.
