Study On The Treatment Of Rural Domestic Sewage Using Mini Constructed Wetland & Landscape Water Body Construction

With the economic development and improvement of growth in the living standard, the home scrap pollution is worse and worse in country-side village and small town. Apparently, a practical and effective solution is needed. Therefore this paper with the needs of New-Rural-Construction, proposed the concept of establishing the rural ecological drainage system. The ecological toilet, which can separate the waste water from the toilet waste, was constructed to replace the pit toilet. This can reduce the concentration of the pollutants of domestic sewage. Then use the constructed wetland technology treat sewage. This paper focuses on the study of using integrated vertical flow constructed wetland (IVCW) key technology treat domestic gray water deeply. As live scattered in rural areas, there is some open space in courtyard. So treatment scattered in a single household sewage is the idea of using the construction of wetlands in the form of micro-vertical-flow wetland. For the removal effect by microbiological in wetland system is low, raised increasing carbon and reaeration in wetland in improving and promoting the removal of nitrogen, phosphorus and so on.Furthermore, the outlet water from the wetland can meet the environmental quality standard of surface water, which is better than outlet water from the municipal wastewater plant.The environmental monitoring was carried out on the IVCW base. The variation of pollution concentration in IVCW was studied by adjusting the hydraulic load, oxygen condition and denitrification condition, then the pollution reduction principle was analyzed. The result indicated that hydraulic load influence the removal of contamination was obvious and great; Because of the concentration of oxygen is lower when the wetland doesn't aerate, nitration is scarcity and so as to denitrification .The removal of nitrogen in wetland depend on adsorption and interception by substrates. The nitration increase when the wetland aerate, and nitrogen transform to nitrate. Because of the concentration of organic carbon is low before add carbon rescue, denitrification is limited .So the concentration of nitrate is high. After adding carbon rescue in wetland denitrification is sufficiency. The concentration of nitrogen is very low. TheⅢsurface water environmental quality standards can be obtained for TN, NH3-N, COD except for TP inⅣstandard rank by reasonable combination of conditions.Furthermore, the carbon source material was studied in the thesis. The branch crumb was selected as the adding carbon source by beaker test to denitrification. Regard branch crumbs as the research object and set up the experiment of hydrolyze -- denitrification . Using droplet straining type reactor and inundator reactor carry on the experiment separately. Because of the difference of fashion of inlet, the hydraulic retention time (HRT) of up inlet reactor is so short. The hydrolyze of cellulose and denitrification can not occur. So the effect of nitrogen removal is bad. The inundator reactor perform better because of the detention time extension.In order to study branch crumbs as carbon source forward and more details in denitrification, the beaker tests were carried out to measure the velocities of denitrification in different temperature and variation PH values, then the optimal condition was achieved. The optimal temperature was 25～33℃for Hydrolysis-Denitrification reaction and 7～8 for optimal PH values.The variation of branch crumbs for continuing reactor was studied since the branch amount was a significant factor in the whole reaction. The result showed that branch crumbs amount was not the only factor for the reaction and the results was effected by combined actions of many factors, including surface area of the branch crumbs, microbial biomass in the surface of branch crumbs, branch crumbs amount, variation of detention time, retarding effect by the reaction products and so on. The experimental result was effected by the co-action of these factors.Finally, the constructed wetland was applied in Nanzhuang Cun, Cuicui town, Changping District Beijing. The domestic waste water was treated by constructed wetland. The investment for the waste water treatment was less than 90,000 RMB for the whole village, and the operation cost was also cheap as less than 0.1 RMB per ton. This technology was obviously better than traditional central waste water treatment technique.