Study On Rural Sewage Treatment By Wastewater Land Anaerobic Purification System

Wastewater land anaerobic purification system is an ecological wastewater treatment technology by artificial enhancement, which uses an ecosystem composed by Soil-Microorganism-Plant to purify pollutants and improve effluent quality. The pollutant removal mechanism of wastewater land anaerobic purification treatment includes decomposition of microorganism, absorption of vegetation and physiochemical effect of substrates. The wastewater land anaerobic purification treatment has the following advantages: low construction investment and operating costs, simple management, stable operating, better removal efficiency, great compatibility to loading changing, salient profit of ecological surroundings and effluent reusing, etc. It's suitable for small-scale sewage treatment, such as towns and villages.DongDazhai village, Lai Xi city built the Wastewater land anaerobic purification system in 2006 to process the village's wastewater, in order to know the draining conditions of the village, study the influence factors of pollutant removal of the Wastewater land anaerobic purification system, so we have Experimented, the Experiment contains two parts:Firstly, to investigate the fluctuation of the wastewater, because the sewage treatment station collecting the wastewater from the district of new village only and the wastewater from the district of old village inflows to the Landscape river, so we investigated the fluctuation of the wastewater from the district of new village only. according to the investigation: the sewage quantity of February drained was the most ,achieving to 3076.07m~3,the least month is May, the sewage quantity was 408.43m~3, the month variation coefficient Km=2.17. The maximum flow rate of day and night sewage was 1.715m~3/10min, and the average flow rate was 0.903 m~3/10min, 10 minute variation coefficient K10min=1.90; the wastewater which flow to the sewage treatment station ,it's average concentration of various pollutant, CODCr=69.45mg/L, TP=1.66 mg/L,NH4+-N =17.28mg/L.Secondly, to study the influence factors of pollutant removal effect of the Wastewater land anaerobic purification system, according to the experiment: except pH, temperature, HRT, the Hydraulic Load, the COD volume load are the main reasons, when the water temperature was more than 22 degrees, the pollutant removal effect was better than the temperature was below 10 degrees; with the increasing of HRT, pollutant removal ability of the system was Strengthening, the best HRT of the system is 19.31~22.5h; with the increasing of the Hydraulic Load and the COD volume load, pollutant removal ability of the system was becoming lower, the best Hydraulic Load and the COD volume load is 0.05m~3/m2.d and 0.01kgCOD/m~3.d respectively; in the course of the experiment, the effluent CODcr of the wastewater land anaerobic purification system is lower than 60mg/L, achieving the first level B criteria ,but TP and NH4+-N aren't satisfy the first level B criteria.