人工湿地系统对生活污水中类固醇激素的去除效果

为了考察建立在室外的12个不同基质(牡蛎壳、沸石、麦饭石、陶粒)、不同水力负荷(HLP=10、20、30 cm/d)的中试人工湿地(CWs)对常规污染指标(COD、TN和NH₄⁺-N)和激素的去除能力差异,筛选出最优的湿地基质种类和水力负荷,同时通过污染物通量核算推断出湿地系统对激素的去除途径.结果表明:在进水中共检出9种激素,包括雄烯二酮、17α-勃地酮、17β-勃地酮、1,4-雄烯二酮、雄酮、羟孕酮、甲孕酮、黄体酮及睾丸素,质量浓度在6.32～1 113 ng/L范围内;不同设计参数下的湿地单元对常规污染指标和激素的去除效果差异较大,对所有检出激素的总去除率为27.7%～94.9%; COD、TN、NH₄⁺-N的日去除通量分别为3.81～10.10、0.42～1.07、0.31～0.80 g/d,所有检测出的激素日去除通量为14.16～28.65μg/d.综合考虑湿地系统对常规污染指标、激素的去除率和去除通量的影响发现:以沸石为基质、水力负荷为20 cm/d的湿地单元为最佳选择.质量平衡核算结果...

The Effect of Constructed Wetlands on Removing Steroid Hormones in Domestic Sewage

The potential of removing steroids in raw domestic wastewater with various mesocosm-scale horizontal subsurface-flow constructed wetlands (CWs) with different design parameters is assessed. Twelve CWs with three hydraulic loading rates (HLR=10, 20, 30 cm/d) and four substrates (oyster shell, zeolite, medical stone and ceramic) were set up outdoors in order to obtain the optimum design parameters of CWs. Meanwhile, the pollutant removal mechanism with CWs was deduced with the mass balance analysis. The result showed that 9 target steroids including 4-androstene-3, 17-dione, 17α-boldenone, 17β-boldenone, androsta-1, 4-diene-3, 17-dione, androsterone, hydroxyprogesterone, medroxyprogesterone, medroxyprogesterone and testosterone were detected in the effluent. The concentrations ranged from 6.32 to 1 113 ng/L. The CWs with different design parameters had variable removals of conventional pollutants and steroids. The total removal rate of all detected steroids was between 27.7% and 94.9%. The calculated daily mass removals of COD, TN, NH₄+-N and steroids with the twelve CWs were 3.81~10.10, 0.42~1.07, 0.31~0.80 g/d, and 14.16~28.65 μg/d. Considering their aqueous removal rates in combination with their mass removals, the CW with zeolite as the substrate and with HLR of 20 cm/d was selected as the best. The results indicated that both biodegradation and substrate adsorption were responsible for the fate of steroids in the wetlands, but biodegradation was the most important process in the removal of these pollutants.