Anaerobic Biological Filter - Combinations Of Return Flow Constructed Wetland Process Research Of Rural Domestic Sewage

Compared with the traditional urban sewage treatment process，artificial wetlandsewage treatment process has been widely used for its lower capital cost and runningcost. But as the removal rate on nitrogen and phosphorus of the process is poorer, andwider use of wetland in higher demand area is seriously constraint by the problem thatthe process packing vulnerable to jam and service life is short.The research use the anaerobic bio-filter——the back-to flow of artificial wetlandcombination process treats rural domestic sewage First, the author discussed the type ofanaerobic filter, the height of the filter and the time of hydraulic loading are influent onSewage treatment effect. Second, the author Discussed the flow back to do artificialwetland plants turn water depth of water flow times the effects of the rich oxygen. Third,the author analysed the effect of removing pollutants by the integrate technique ofanaerobic filter and constructed wetland as well as the impact of seasonal variation on itof anaerobic bio-filter back line flow constructed wetland in different seasons ofpollutant removal effect; Finally, through engineering practice, the practical applicationeffect on this technique was tested. The following results were obtained:（1） Cobbles of20-30mm in grain diameter and200mm in height were selected assupporting layer of the anaerobic filter, and sandy soil, gravels of5-10mm,2-4mm and20-25mm, in a height of1,000mm were respectively selected for the filler layer. Theremoval rate of COD_cris60.2%、57.8%、53.1%;（2） Select gravels of2-4mm as the filler, In a height of800mm,1000mm,1,200mm,the removal of COD_cris56.3%、66.8%、67.1%；（3） Select2-4mm in diameter of gravel, the height is1000mm, stay in time for the12h, Compared with initial stage, The removal rate of COD_cris reduced by10%.（4） The back-to flow of artificial wetland oxygen enrichment with water turbulentstate, return number increase DO content increases;（5） In accordance with definite technological parameters, the removal rate for COD_cr,NH4+-N, TP and SS was72.8%-79.6%、26.5%-48.1%、33.3%-59.6%and77.0%-84.0%successively, with effluent meeting the standard of Grade II in Discharge Standard ofPollutants for Municipal Sewage Treatment Plant（GB18918-2002）;（6） In practical application and under the circumstances of a certain difference inelevation, the integrated technique of anaerobic filter and constructed wetland canachieve unpowered operation. Besides, it is easy to implement this technique, the dailymanagement and protection work load is small, the operational cost is extremely low,and it is easy to integrate with the landscape construction in camps;Therefore, it is anecological technique for treating domestic sewage with military features.