| The analysis and research on current situation of the emissions and treatment of the rural sewage is carried out. It is put forward that rural areas should adjust measures to local conditions to select the appropriate mode of decentralized wastewater treatment. Considering geographical landform, topography, soil type and climatic conditions and other factors, a four levels six programs system of rural decentralized wastewater treatment mode and evaluation method which is suitable for rural regional characteristics in China is established by using improved analytic hierarchy process, in order to help rural place to solve the sewage problem.Decentralized Wastewater Treatment Planning Model is constructed for rural decentralized wastewater treatment mode planning and evaluation, which based on Yahhp software. It makes the complex calculation process realized the digitization and friendly man-machine visualization. The decentralized wastewater treatment mode planning and evaluation of Shuangfengshan village in Jiao Nan is finished by using D.W.T.P. Model. GIS and D.W.T.P. Model is coupled by creating a spatial database and combining the spatial database and relevant mathematical model through programming. It has carried out the regional decentralized wastewater treatment mode planning and evaluation for part of the village areas in Jiao Nan.Constructed wetland wastewater treatment system is chose to simulate, analyze and evaluate in laboratory. Experimental results show that the removal rate of CODcr, TP and NH4+-N increases with increasing hydraulic retention time, also increases with increasing temperature by sandstones treatment. At an ambient temperature of15℃, CODcr can be reduced from252mg/L to52mg/L for4days hydraulic retention time, the removal rate is79%. Keep5days hydraulic retention time, TP can be reduced from3.49mg/L to1.01mg/L, the removal rate is74%, NH4+-N can be reduced from20.38mg/L to8.00mg/L, the removal rate is61%. The subsequent activated carbon or coal gangue treatment can further reduce the TP to0.15mg/L, removal rate is85%, reduce the NH4+-N to4.66mg/L, removal rate is42%.On this basis, the demonstration project of Jimo fifth high school is designed, evaluated, established, operated and monitored. The constructed wetland wastewater treatment system is determined the best choice by using D.W.T.P. Model. After six months of trial operation, the treatment effect is proved good and the effluent can meet the discharge standards. The demonstration project has important reference value to the popularization and application for the decentralized wastewater treatment in rural place in our country. |
