间歇式生物反应器中PHACs的吸附降解性及动力学特性

利用间歇反应器考察了非那西丁(PNT)、吉非罗齐(GFZ)、咖啡因(CAF)、双氯芬酸(DCF)和胆固醇(CH)5种医药类污染物分别在厌氧、缺氧及好氧条件下的吸附与降解特性,并通过动力学拟合深入考察目标物的降解速率及所符合的反应级数.研究表明,PNT在4 h内就能得到100%的降解,GFZ与CH能通过吸附与降解得到部分或全部去除.好氧条件下目标物的泥水分配系数kp值与降解速率均高于缺氧与厌氧条件,好氧条件下CAF的去除率达到99%以上.5种目标物除PNT外都有不同程度的吸附,目标物的污泥吸附能力为CHDCFGFZCAF;动力学拟合结果表明,生物降解动力学一级反应速率PNTCAF,二级反应速率CHGFZ;DCF几乎不能被生物降解,但符合二级吸附动力学模型,其平衡吸附量最高可达总投加量的71%.

Adsorption, biodegradation and reaction kinetics of pharmaceuticals in a batch bioreactor

Adsorption and biodegradation of phenacetin (PNT), gemfibrozil (GFZ), caffeine (CAF), diclofenac acid (DCF) and cholesterol (CH) were investigated in a batch reactor under anoxic, anaerobic and aerobic conditions, respectively. The degradation rates and reaction orders of target pollutants were also investigated. It was shown that PNT could be entirely degraded in 4 h, CH was removed completely through adsorption and degradation, and GFZ was biodegraded partially. The sludge-water partition coefficients (k_p) and degradation rates of the pharmaceuticals under aerobic condition were higher than those under anaerobic and anoxic conditions, and the removal efficiency of CAF was more than 99% under aerobic condition. The k_p of CAF was more steady than GFZ and DCF, and the fluctuation of the k_p of GFZ was the largest. All pharmaceuticals except PNT had been adsorbed in activated sludge in some degree, and sludge adsorption capacities were in the order of CH>DCF>GFZ>CAF. Degradation rate of PNT was higher than CAF under first order reaction and biodegradation of CH was higher than GFZ under second order reaction, but DCF could hardly be degraded while it fit second adsorption reaction and the equilibrium adsorption amount could reach 71% of total input amount.