Transfer-transformation Rules Of Pharmaceutical Pollutants In The Reversed A~2/O Process Of A Municipal Sewage Treatment Plant And Its Process Evaluation

With the development of society and the improvement of human to water qualityrequirements, in addition to the improper use of drug by human beings and animals,pharmaceutical pollutants can be detected generally with high concentration inenvironment, thus it has potential risk to human health and environment. The removalto the pharmaceutical pollutants still being studied at present, there is no targetedtreated process to the pharmaceutical pollutants, So a set of treated process which iscomplete and reasonable can both do not affect its removal efficiency to the commonnutrient in sewage and have good removal effect to the pharmaceutical pollutants needto be established. This paper studies the removed rule to the pharmaceutical pollutantsin sewage by tested samples which were inflow and effluent from different structuresin urban sewage treatment plants,make the effluent of urban sewage treatment plant noharm to ecological environment,and can still provide reliable useful data to treatedprocess of level3of sewage.Regarding the fourth wastewater treatment plant in Xi’an as the researchsubject，This paper determined4target compounds, respectively were Phenacetin、Caffeine、Gemfibrozil and Cholesterol, develop research work through the stationingsampling testing analysis to inverted A~2/O (anoxic anaerobic aerobic) process. Thisresearch found that the annual average concentration of inflow of Phenacetin、Caffeine、Gemfibrozil and Cholesterol were respectively5.01g/L、100.59g/L、8.82g/L and5.82g/L, Caffeine, a kind of common nervous drug which has a highcapital usage, its concentration is far higher than other three pharmaceuticalpollutants.Through the analysis to the process,we found that Phenacetin、Caffeine and Cholesterol were removed mainly by the primary treatment and the secondprocess,their concentration in the secondary effluent and sludge were relatively low;while Gemfibrozil were removed much higher than other three pharmaceuticalpollutants by sludge adsorption,which conform to its larger logKow,because it hasstrong hydrophobic and sludge adsorption.For the inverted A~2/O process, Phenacetin、Caffeine and Gemfibrozil were mainly removed by aerobic microorganism,whileCholesterol were removed mainly by anaerobic microorganism. Although the removalrate of the pharmaceutical pollutants in sewage by the treatment process were higherthan90%,the average concentration of Phenacetin、Caffeine、Gemfibrozil andCholesterol in floating oil of aeration sink sand pool respectively were2.49μg/L、44.37μg/L、3.47μg/L and2.52μg/L,and the average concentration of Phenacetin、Caffeine、Gemfibrozil and Cholesterol in sludge respectively were0.03μg/g、2.04μg/g、6.78μg/g and0.73μg/g.By the study we know that the pharmaceutical pollutants in sewage were onlyabout50%be removed by the sewage treatment process,while the rest were flow intothe environment through other ways.So the pollution of environment caused by thepharmaceutical pollutants first should be controlled from the source,second thetreatment process should be thought.