农村生活污水生物-生态组合工艺净化效果及长效管理研究

Study on Purification Effect and Long-Term Management of Bio-Ecological Combined Process for Rural Domestic Sewage

关键词:  农村生活污水  生物生态组合处理  季节效应  去除效率  长效管理

Key words:  rural domestic sewage  bio-ecological combination treatment  seasonal effect  removal efficiency  long-term management

摘要:

相比城镇地区，农村生活污水排放分散、基础处理设施薄弱、管理维护难度大，因此本研究采用“厌氧池+生物滤池+潜流人工湿地(简称“人工湿地”)+氧化塘”的组合工艺，考察分析组合工艺各处理单元对广西桂林农村地区各污染物的去除特性。结果显示，组合工艺中生物滤池对化学需氧量(COD)、氨氮(NH₃-N)的去除效果最好，夏季去除贡献率分别为75.36%和66.46%，冬季分别为67.96%和57.13%；而人工湿地对总氮(TN)、总磷(TP)的去除贡献率最大，夏季去除贡献率分别为65.08%和63.97%，冬季分别为53.15%和62.87%，并且不论夏季还是冬季，芦苇混合美人蕉湿地与菖蒲混合鸢尾湿地对 COD、TN、NH₃-N 及TP去除效果均较好，二者的出水浓度均能满足一级B排放标准；氧化塘作为最后的处理单元，各生态净化功能区深度去除污染物，其中水生植物区对于TN、TP及NH₃-N的平均去除率最高，水生动物区则在COD的去除方面有明显的优势，夏、冬季氧化塘平均出水浓度均能较稳定达到一级A排放标准。另外，针对农村污水设施对污染物去除率随运行年限延长而下降的现象，提出对组合工艺各处理单元加强防堵塞和及时收获植物动物的长效管理建议，为保障污水处理设施长久治污效果提供参考。

Abstract:

Compared with urban areas,rural domestic sewage discharge is scattered,basic treatment facilities are weak,and the management and maintenance are difficult. Therefore,in this study,the combined process of “anaerobic tank+biological filter+subsurface flow constructed wetland (referred to as “artificial wetland”)+oxidation pond” was used to investigate and analyze the removal characteristics of each treatment unit of the combined process on various pollutants in rural areas of Guilin,Guangxi. The results showed that the biological filter had the best removal effect on Chemical Oxygen Demand (COD) and Ammonia Nitrogen (NH₃-N) in the combined process. The removal contribution rates were 75.36% and 66.46% in summer,and 67.96% and 57.13% in winter,respectively. The artificial wetland had the highest contribution rates to the removal of Total Nitrogen (TN) and Total Phosphorus (TP),with removal contribution rates of 65.08% and 63.97% in summer and 53.15% and 62.87% in winter,respectively.Moreover,regardless of whether it was summer or winter,the reed mixed canna wetland and the calamus mixed iris wetland had good removal effects on COD,TN,NH₃-N and TP,and their effluent concentrations both could meet the first level B emission standard. As the final treatment unit,the oxidation pond deeply removed pollutants in various ecological purification functional areas. Among them,the aquatic plant area had the highest average removal rate for TN,TP,and NH₃-N,while the aquatic animal area had obvious advantages in COD removal. The average effluent concentration of the oxidation pond in summer and winter could reach the first level A emission standard stably. In addition,in view of the phenomenon that the removal rate of pollutants in rural sewage facilities decreased with the increase of operating years,long-term management suggestions for strengthening anti-clogging and timely harvesting of plant animals in each processing unit of the combined process were proposed to provide reference for ensuring the long-term pollution control effect of sewage treatment facilities.