某污水处理厂倒置A2/O工艺中制药类污染物的去除规律分析

针对西安市某污水处理厂的倒置A2/O工艺,通过对主要构筑物的布点检测,分析了污水中4种制药类污染物非那西汀、咖啡因、吉非罗齐和胆固醇的浓度变化及其去除规律.结果表明,污水厂进水中非那西汀、咖啡因、吉非罗齐和胆固醇的浓度分别为8.22、127.31、12.93和5.61μg·L-1,整个污水处理工艺中,非那西汀、吉非罗齐和胆固醇主要是被格栅、曝气沉砂池和初沉池去除,咖啡因则以生物降解为主.A2/O生物反应池中,吉非罗齐和胆固醇以厌氧生物降解为主,非那西汀和咖啡因则以好氧生物降解为主.脱水污泥中非那西汀、咖啡因、吉非罗齐和胆固醇的含量分别为0.09、2.62、12.24和0.91μg·g-1,污泥对吉非罗齐的吸附效果最为显著.污水厂出水中制药类污染物的浓度为0.17～1.98μg·L-1,出水中咖啡因的浓度偏高因而需要做进一步的三级处理.

Study on the removal mechanism of pharmaceutical pollutants in wastewater by the reversed A2/O process

In this paper, the concentration changes and removal mechanism of four pharmaceutical pollutants in wastewater, named phenacetin, caffeine, gemfibrozil and cholesterol, generated by the reversed Anoxic-Anaerobic-Oxic (A2/O) process, were studied on the basis of stationing and sampling analysis for a sewage treatment plant in Xi′an city. The results indicated that, the influent concentrations of the four pollutants were 8.22 μg·L-1, 127.31 μg·L-1, 12.93 μg·L-1and 5.61 μg·L-1, respectively, and physical methods, such as grid, aerated grit chamber and primary settling tank, were the effective manners to remove phenacetin, gemfibrozil and cholesterol, while microbial degradation played a key role for caffeine removal. For the reversed A2/O biological system, most of gemfibrozil and cholesterol were degraded by anaerobic bacteria, and most of phenacetin and caffeine were removed by aerobes. In order to analyze the effect of sludge adsorption, concentrations of phenacetin, caffeine, gemfibrozil and cholesterol in dewatered sludge were measured to be 0.09 μg·g-1, 2.62 μg·g-1, 12.24 μg·g-1 and 0.91 μg·g-1, respectively, and the adsorption of sludge to gemfibrozil was remarkable. Concentrations of target pharmaceuticals were approximately 0.17~1.98 μg·L-1 in the treated effluent of the sewage treatment plant. Caffeine concentration was still high that needed further tertiary treatment.