Abstract
Alkylphenols are used in various industries in Japan. These substances are found to be endocrine disruptors that affect the gonad system. One alkylphenol that is often detected in the aquatic environment and has been found to have an estrogenic effect is nonylphenol (NP). The objectives of this study were to degrade NP using chlorine and ozone, the two major disinfectants used in treatments of drinking water and wastewater, and to investigate the effects of other coexisting substances. The results showed that NP in buffered water could easily be degraded by chlorine and ozone. The presence of ammonia however affected the degradation of NP by chlorine. Humic acid showed a negative effect on the removal of NP by chlorine and ozone but the effect of humic acid was small. Comparison of the amount of total chlorinated carbon (TOX) formed during chlorination of buffered NP solution and of sewage effluent was likewise conducted. Under normal chlorination conditions, the amount of TOX formed per mg dissolved organic carbon (DOC) was higher in buffered NP solution (138μg-Cl/mg-DOC) than in sewage effluent (84μg-Cl/mg-DOC). The results of the study further showed that 15-min chlorine contact time considerably decreased the NP concentration and its estrogen receptor binding effect. The aromatic ring however was not decomposed. Degradation of the aromatic ring was only observed after 24-h contact time. Ozone contact time of 1-min was found to degrade the aromatic ring.
