[Adsorbable organic halogen compounds and bio-toxicity in hospital wastewater treatment].

Adsorbable organic halogen compounds (AOX) exist persistently in the aquatic environment, and accumulate in the food chain. Some of them are toxic for humans and other organisms. However, hospital wastewater is considered as an important source of AOX in municipal wastewater. The aim of this study was to evaluate the generation of AOX both in a raw hospital wastewater and the effluent from a membrane sequencing batch reactor, also the effect of cR t value and the bio-toxicity were investigated. The results show that the removal of AOX in the hospital wastewater is 63.6% after treated by the membrane sequencing batch reactor, and the contribution of membrane rejection accounts for 14.5%. The concentration of AOX in the raw hospital wastewater is much higher than that of the effluent from membrane sequencing batch reactor at the same value of cR t for its higher chlorine-demands. Along with the increasing of cR t value, the fitting curves of AOX present exponential growth for the raw hospital wastewater, while linearity relation for the effluent from membrane sequencing batch reactor. To meet the requirement for indicative microorganism (fecal coliform) in the Discharge Standard of Water Pollutants for Medical Organization (GB 18466-2005), the demands of cR t value for the raw hospital wastewater and the effluent from membrane sequencing batch reactor are 5.5 (mg x h)/L and 0.0075 (mg x h)/L respectively, the bio-toxity by acute toxicity test with Daphnia magna are 40.39 microg/L (K2Cr2O7) and 8.96 microg/L (K2Cr2O7), and correspondingly the concentration of AOX produced are 607.1 microg/L and 102.5 microg/L.