[Assessing the ecological risk of effluents from different advanced treatment units by using a battery of bioassay]

In this paper, effluents from different advanced treatment units, which were reclaimed for Olympic Park, were assessed regarding to the removal efficiencies of the technologies on acute toxicants, Ah-acceptor chemicals and estrogenic substances by using a battery of bioassays. The results showed that advanced treatments using ultra-filtration and activated carbon absorption were suitable for removal of toxic organic substances from STP effluent. Activated carbon absorption was the most effective technology to remove acute toxicants and Ah-acceptor chemicals, and the removal efficiency of Ah-acceptor chemicals reached 98%. Ultra-filtration was suitable for removing nonpolar acute toxicants and polar estrogenic chemicals. Nonpolar fraction extracted from water after ultra-filtration treatment showed 100% percentage survival of cell in the acute toxic assay. E2-TEQ was reduced from 0.13 pmol x L(-1) to 0.04 pmol x L(-1) in the polar fraction extracted from water after ultra-filtration. Treatments with micro-filtration and osmosis did not manifest sufficient efficiencies for removal of toxic organic substances. In complex matrix, interactions may occur among different toxic components to interfere the bioassay results. Therefore fractionation of organic concentrate before bioassay is necessary.