摘要:
通过12个月的现场监测试验,研究了活性污泥法与四个串联潜流人工湿地构成的组合处理系统对农村生活污水的处理效果及其影响因素.结果表明,当平均处理量为82T·d-1(36—132T·d-1),湿地系统水力负荷为0.52—1.88m·d-1时,组合处理系统对TSS,AN,TP,COD和BOD5的去除率分别为75%,71%,38%,81%和88%;湿地系统对COD,BOD5,SS,AN和TP的去除率分别为39%,55%,48%,5%和18%.方差分析表明,影响组合系统处理效果的主要因素是水力负荷及处理单元;湿地系统中有机污染物(COD,BOD5,SS)的去除主要是由第一块湿地完成的,而AN及TP的去除却呈现"累积"的特点;结合电子受体SO42-,NO3-及NO2-在湿地系统中的浓度变化趋势,推测湿地系统中有机污染物的生物去除主要是通过反硝化脱氮进行的,而通过硫酸盐还原(在硫酸盐还原菌的作用下)却是次要过程.
Abstract:
A pilot-scale wastewater treatment system combined by activated sludge and four subsurface constructed wetlands in series was sampled for one year to study the system performance for common contaminants in countryside wastewater.Yearly average results showed that when the average wastewater flow was 82 T·d-1(36—132 T·d-1) corresponding to hydraulic loading rate of 0.52—1.88m·d-1,the combined system removed 75% of the TSS,71% of the AN (ammonium),38% of the TP,81% of the COD,and 88% of the BOD5,respectively.The constructed wetlands system removed 39%,55%,5%,18% and 48%,of COD,BOD5,AN,TP and SS,respectively.ANOVA statistical analysis performed on the data set of 12 months of operation showed that the hydraulic loading rate(HLR)and the treatment unit were major factors that control the performance of combined system for the target pollutants.Significant removal of organic matter such as COD,BOD5and SS in the constructed wetlands system was found in the first constructed wetland,however,a accumulative removal was found for nutrient matter such as AN and TP.A survey of electron acceptors such as SO42-,NO3-and NO2- in the constructed wetlands system indicated that denitrification was estimated to be significant for organic matter removal in constructed wetland beds,in contrast,the organic matter removal by sulfate reduction was minor.
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