Production And Discharge Characteristics Of Rural Sewage And Purification Efficiency From Artificial Wetlands To Rural Domestic Sewage In Draw-down Areas Of The Three Gorge Reservoir

With the continuous change of living level and the way of life in the Three Gorges area,Water pollution of the Three Gorges area from agricultural non-point source is worse and worse,it is urgent to study the influence of water quality in the Three Gorges area from rural sewage,which is an important source of agricultural non-point source pollution.As the running of Three Gorges reservoir,the water level changes around 145m to 175m,a large reservoir which is called The riparian zone will come out.maybe bring about a series of ecological problems,Therefore exploring an effective use of riparian zone of idle land in rural wastewater pollutants removal method,can reduce pollution emissions to the reservoir water utilization mode of the delay,on the rational use of fluctuating with land and protect reservoir water ecological environment is of great significance.At first,this artical investigates and monitors the basic characteristic of residents living sewage in Long Wang Gou watershed of the Three Gorges Reservoir area.We construct many artificial wetlands in the riparian zone of Long Wang Gou watershed,as the time of longer hydraulic retention is 7d,14d,21.the potential of purifying rural domestic sewage from different artificial wetlands which is planting different plants?HH,CG,MR,HH,DJ,QQ,XP,ZL,CP,JB,LW,LZ,SD,WC,BQ,ZH,QH,CM,LL,CD?.Screened three suitable artificial wetland plants?lotus water spinach and rice?.Researched efficiency of purifying sewage,explore the best HRT and influent concentration.And explore the potential of purifying rural domestic sewage.The results show:1.The resident population of Long Wang Gou watershed in the Three Gorges Reservoir area is 344,the average values of the daily discharge per household and capita in Three Gorges Reservoir Area is 133.5L and 38.OL,54.5 percent of the rural domestic sewage comes from the kitchen,30.0 percent comes from the laundry,There is only 15.5 percent of sewage comes from the toilet.Water quanlity among different resource differences a lot.The average value of pH of sewage is 7.2,concentrations average of COD,TP,TN and NH₃-N in domestic sewage respectively are 457.6mg·L^-1,4.7mg·L^-1,58.3 mg·L^-1 and 16.2 mg-L^-1.Domestic sewage contaminants that COD,TP,TN and NH₃-N daily capacity per capita respectively are 16.893g/cap·d^-1,0.185 g/cap·d^-1,2.184 g/cap·d^-1,0.641 g/cap·d^-1 Domestic sewage contaminants that COD,TP,TN and NH₃-N daily capacity in the small watershed respectively are 5.811kg,63.64g,751.30g,220.50g.2.Riparian wetland of rural domestic sewage purification experiments show that:with the increase of processing time,the removal rate of COD,TN,NH₃-N and TP form rural domestic sewage of artificial wetland with different plants or plant assemblages will improve.Overall,the efficiency on sewage purification from different combinations of plants is higher than that of single plant wetlands.In processing time was 21 days,influent concentration of COD,NH₃-N,TN,TP mean 1739.00mg·L^-1,1113.60 mg·L^-1,1147.60 mg·L^-1 and 37 mg·L^-1,respectively,different combinations of plant and plant of wastewater COD,NH₃-N,TN,TP average removal rate was 85.53%respectively,99.94%,99.19%,98.83%,except for COD,other indexes reached other pollutant concentrations meet the urban sewage treatment plant pollutant discharge standards?GB18918-2002?level a standard.Thus the purification potential of riparian zone artificial wetlands to sewage is well.3.The test of purification sewage shows that:?The HRT of lotus,water spinach and rice wetland system should be 5d.In the HRT for 5d,lotus and spinach wetland system respectively on the COD,TP,TN and NH₃-N removal rate was the highest,for 88.21%,79.02%and 88.16%,81.23%.?The COD concentration of influent water spinach and rice,lotus wetland system should be 340-460mg/L.Overall,the average removal effect of the 3 plant wetland systems for COD,TP,TN and NH₃-N was C>D>B>A.?Artificial wetland system with 3 water spinach under optimal conditions,on COD,TP,TN and NH₃-N average removal rate were 84.37%and 77.06%,83.18%,75.96%.At this time,TN and NH₃-N effluent can reach urban sewage treatment plant pollutant discharge standards?GB18918-2002?standard of a class a requirements effluent TP concentration up to urban sewage processing plant pollutant discharge standards?GB18918-2002?secondary standard requirements,to within the watershed,generated pollutants COD,TP,TN,NH₃-N daily average removal rate is 1.19%,1.02%,1.16%and 1.00%.Without considering other factors,construction area of 900m2 fluctuating with water spinach constructed wetland to basin generated daily pollutant all cut off.