Research On Intensive Ecological Treatment Mode Of Domestic Sewage In Rural Area

With the development of China’s economy in recent years and the improvementof people’s living standards, especially the development of rural water supply, thedisplacement in rural areas kept increasing. In China, the amount of villages andcounties in rural areas were large and widespread, the sanitary sewage volume wasrelatively small and distributed, and the sewage volume was discharged irregularlyand was hard to control. Therefore, the sewage treatment techniques in cities were notsuitable in rural areas. It is important to develop new technique with low cost, lowmaintenance and high treatment efficiency in rural areas.Combining with the status quo of sewage treatment in rural area of Tianjin andbased on the treatment techniques research in and abroad, the paper put forward a newmode ecological treatment which intensified three technique of anaerobic hydrolysis,aerobic biological contact oxidation and constructed wetland. The paper elaboratedthe characteristics of aerobic biological contact oxidation technique and wavysubsurface flow constructed wetland; problems of the intensive technique in dealingwith sewage treatment in rural areas were discussed. The results showed that theintensive technique could achieve excellent effect in wiping off COD、NH4+-N、TN、TP and SS, and the effluent quality would reach the A standard of the pollutantdischarge standard on sewage treatment plants (GB18918-2002). The removal ratesfor COD、NH4+-N、TN、TP and SS were86.30%、89.60%、72.47%、93.19%and98.2%.Comparing with the single treatment technique, the combination of the threetechniques could make full use of their advantages, and heighten the effluent qualityand the system stability. Preconditioned by the effluent quality, the combingtechnique could shorten the hydraulic detention time and save the volume ofbiological contact oxidation and the space of constructed wetland, and reduce theaeration rate. The technique is an intensive ecological treatment mode, the investmentper ton is RMB4,719.55, and the operation cost is0.134RMB per ton. With theadvantages of good operation effect, low investment, low cost, small amount ofexcess sludge and simple operation, the technique is suitable for sewage treatment inrural areas, and could achieve multiple effects together with ecological and greeningconstruction, which proved the technique was of wide application foreground.