自然曝气生物滤床去除二级污水处理厂尾水中酚类内分泌干扰物的应用

Application of natural-aeration biofilter in removal of phenolic endocrine disruptors chemicals from secondary effluent

采用自然曝气生物滤床工艺对二级污水处理厂尾水进行深度处理。结果表明该工艺可在净化过程中创造良好的好氧环境,对尾水中悬浮颗粒物(SS)、化学需要氧量(COD)和氨氮(NH4+)的去除效率分别可达76%、45%和77%。尾水中可检出不同程度的酚类内分泌干扰物,其中双酚A(BPA)、壬基酚(4-NP)、辛基酚(4-t-OP)、三氯生(TCS)和雌酮(E1)的浓度在1～1639 ng/L之间,未检出雌二醇(E2)和炔雌醇(EE2)。该工艺可显著削减上述有机微污染物的含量,去除效率分别可达49%、63%、78%、80%和46%。4-NP、4-t-OP和TCS的去除效率随水力负荷(HLR)减小而升高,E1的去除效率不随HLR变化而变化,BPA的去除效率随HLR减小而下降,主要因为强疏水性有机物可在吸附竞争中降低疏水性较弱的有机物在系统中的吸附能力。

A natural aeration biofilter was employed to treat the secondary effluent. Results showed that a favorable aerobic condition could be created by the biofilter. And the biofilter showed good performance on removal of SS, COD and NH4＋, with values of 76%, 45% and 77%, respectively. Individual concentrations of phenolic endocrine disruptors （EDCs） in secondary effluent ranged from 1 to 1639 ng/L for biophenol A （BPA）, 4-nonylphenol （4-NP）, 4-t-octylphenol （4-t-OP）, triclosan （TCS） and estrone （El）, whereas estradiol （E2） and ethinylestradiol （EE2） were not detected. Natural aeration biofilter could significantly reduce content of above micropollutants with removal efficiency of 49%, 63%, 78%, 80%, and 46%, respectively. Furthermore, the effect of HLRs on the removal of EDCs was elosely related to the hydrophobicity of chemicals. Removal rates of 4-NP, 4-t-OP and TCS went up with decreasing HLRs, while that of BPA performed the opposite. Moreover, removal rate of E1 represented no changes with varying HLRs. The main reason should be that the adsorption affinity of organics with weak hydrophobicity would be lessened by those with strong hydrophobicity.