Estrogen toxicity reduction of industrial biochemical tailwater by electrolysis biofilters with ceramsite‑sulfur-siderite fillers

Abstract

Biochemical tailwater of the industrial park wastewater treatment plant is facing the growing demand of advanced treatment and toxicity reduction. However, existing information on toxicity reduction of real industrial biochemical tailwater is still limited so far. Herein, the water quality of biochemical tailwater from an integrated industrial park in Taihu Lake Basin, China, was systematically investigated, and typical endocrine disrupting chemicals (EDCs) and estrogen toxicity were detected. Estrogen toxicity reduction by previously proposed electrolysis biofilters with ceramsite‑sulfur-siderite fillers was further verified. Results showed that total nitrogen (TN) and estrogen toxicity removal increased by 41.0 % and 30.3 % respectively under the optimal voltage of 4 V and electric loading of 24 h/d, and significantly positive correlation between estrogen toxicity reduction and TN removal (p < 0.05) was observed. The lowest effluent estrogen toxicity was 0.79–0.95 ngE2/L (in estradiol equivalent concentration) by the biofilter with ceramsite‑sulfur-siderite fillers, which was lower than the estrogen disruption effects mass concentration threshold of 1 ng/L. Electrical stimulation promoted the increase of the abundance of denitrifying bacteria Thauera and electroactive bacteria Hydrogenophaga, thus enhancing the removal of TN, furthermore, the abundance of Thiobacillus and Sulfuritalea were significantly correlated with the reduction of estrogen toxicity. The study highlights the potential of electrolysis biofilter in realizing the synergy of estrogen toxicity reduction and autotrophic denitrification of industrial biochemical tailwater, and paves the way for the application of electrolysis biofilter in the advanced purification of industrial biochemical tailwater.