Effectiveness of ozonation and chlorination on municipal wastewater treatment evaluated by a battery of bioassays and biomarkers

摘要

A battery of bioassays, including biological toxicity as well as in vitro mouse spleennlymphoproliferative responses and cytokine production, was conducted to comparenthe effectiveness of tertiary treatment methods such as coagulation (Coag) and absorptionnon granular activated carbon (GAC) and disinfection processes such as chlorination and ozonationnin removing toxic or stress inducing agents from reclaimed wastewater. Whole effluent toxicityn(WET) testing of secondary treated (ST) wastewater using as test species Vibrio fischeri, Daphnianmagna and Tetrahymena thermophila as well as phytotoxicity revealed moderate toxicity effectsnthat depend on the organism used. All bioassays exhibited decrease of the ecotoxicologicalnresponses after tertiary treatment. However, mitogenic responses were proved to be morensensitive. Endotoxin present in ST samples may be responsible for the increased strongnlymphoproliferative activity as well as interleukin-1 (IL-1) production by mouse splenocytes.nTertiary treatment of ST with coagulation and/or adsorption on granular activated carbon (GAC)nin combination with ozonation reduced WET to control levels. Ozonation alone or in combinationnwith any other treatment removed endotoxin more efficiently than chlorination and thus reducednspleen lymphoproliferative responses and IL-1 production.