污水处理厂芳香烃和氯代烃逸散速率研究

以哈尔滨某城市污水处理厂中的芳香烃(苯,甲苯,二甲苯)和氯代烃(三氯甲烷,四氯化碳三氯乙烯,四氯乙烯)为研究对象,应用不同的数学模型计算了在不同季节条件下其在格栅、初沉池、生化池(厌氧段和曝气段)、二沉池处理单元中的逸散速率.结果表明,芳香烃和氯代烃在生化池逸散速率最高,苯和三氯乙烯的逸散速率分别为1.92~5.22g/s和16.94~18.8g/s.芳香烃逸散速率不符合《大气污染物综合排放标准(GB16297-1996)》.芳香烃的逸散速率在生化池中下降很快,而氯代烃的逸散速率比较稳定.芳香烃和氯代烃在格栅的逸散速率最低,二甲苯和三氯甲烷的逸散速率分别为12.94×10-6~17.24×10-6g/s和1.88×10-6~2.58×10-6g/s.在沉淀池中,芳香烃和氯代烃春季逸散速率平均为夏季的1.7倍.春季二沉池苯、甲苯和二甲苯的逸散速率分别为初沉池的59.2%,53.3%和4.5%;而二沉池氯代烃逸散速率增加了13%.

Emission rates of aromatic hydrocarbons and chlorinated hydrocarbons at a wastewater treatment plant

The emission of aromatic hydrocarbons(benzene,toluene,and xylene) and chlorinated hydrocarbons(chloroform,carbon tetrachloride,trichloroethylene,and tetrachloroethylene) at a municipal wastewater treatment plant in Harbin was studied to calculate their seasonal emission rates from screen room,primary clarifier,biochemical tank(anaerobic and oxic stages),and secondary clarifier by applying different mathematical models.The highest emission rates of aromatic hydrocarbons and chlorinated hydrocarbons were observed for the biochemical tank,which were 1.92~5.22g/s for benzene and 16.94~18.8g/s for trichloroethylene,respectively.The emission rates of aromatic hydrocarbons failed to meet the criteria of Integrated Emission Standard of Air Pollutants(GB16297-1996).The emission of aromatic hydrocarbons decreased quickly along biochemical tank,while that of chlorinated hydrocarbons kept constant.The lowest emission rates of aromatic hydrocarbons and chlorinated hydrocarbons were observed for the screen room,which were 12.94×10-6~17.24×10-6g/s for xylene and 1.88×10-6~2.58×10-6g/s for chloroform,respectively.In the primary and secondary clarifiers,the average emission rates of aromatic hydrocarbons and chlorinated hydrocarbons in spring were 1.7 times of those in summer.In Spring,the emission rates of benzene,toluene and xylene in the secondary clarifier were 59.2%,53.3%,and 4.5% of those in the primary clarifier,while the average emission rates of chlorinated hydrocarbons in the secondary clarifier was increased by 13%.