Investigation On The Present Situation Of Water Environment And Experimental Study On Rural Domestic Sewage Treatment In Qihe

In recent years,the industrialization and urbanization process was pushed forward,the society and economy developed rapidly,environmental pollution problems increased accordingly,and the water pollution was particularly prominent.But our country's sewage disposal work was more inclined to urban areas,most rural areas lacked sewerage networks and sewage treatment facilities,domestic sewage was discharged without treatment,a large number of organic matter,pathogenic microorganisms,nitrogen,phosphorus and other nutrients polluted rivers and lakes and other water,and even became a threat to the safety of drinking water of the villagers.As the "beautiful village" construction work continued to advance,the construction of ecological civilization and the renovation of ecological environment in rural areas had become a top priority,rural sewage treatment had become an important manifestation of social material progress and an important measure to ensure the quality of life of farmers,so it was urgent to improve the rural water environment quality.This subject relied on the national major projects for water pollution control and management-the seventh sub-topics of water pollution control and water quality improvement technology integration and comprehensive demonstration in Tuhai River and Majia River Basin,so the paper selected Tuhai River and Majia River Basin representative county-Qihe as a research object,and conducted field research to the county.The results showed that domestic sewage discharge had become one of the main causes of water pollution in Qihe,the discharge of domestic sewage in Qihe was concentrated in the morning and evening of summer and autumn,and the main pollutants were organic matter and ammonia nitrogen.In order to improve Qihe's present situation of water environment,the paper studied several commonly used domestic sewage treatment technology and determined the self-purification method of capillary moistening as a research focus.However,the traditional self-purification method of capillary moistening had problems in soil blockage and nitrogen removal efficiency.So a series of experiments were carried out to improve the method in this paper.Firstly,the removal efficiency of COD,NH₄⁺-N by zeolite,activated carbon,and clay ceramic filler single packing and with a certain volume ratio packing were studied with the method of contrast test.The experimental results showed that the combination and filling method would affect the purification effect of self-purification method of capillary moistening.The treatment effect of three kinds of filler mixed packing was obviously higher than that of single packing,and the effect of complete mixed filling was better than that of layered filling.In addition,zeolite,activated carbon,clay ceramsite volume for 8:3:2 loading way was better than that of 5:4:3 ratio of volume loading way.Therefore,considering both COD and NH₄⁺-N removal effect,the order of the effect of the four systems was system 4> system 3> system 2> system 1.That was to say,the best way to purify contaminants was the volume ratio of zeolite,activated carbon and clay ceramsite by 8: 3: 2.Secondly,operation parameters of self-purification method of capillary moistening were optimized in this paper.The experimental results showed that the change of hydraulic loading and aeration parameters could improve the removal efficiency of the self-purification system of capillary moistening.On the one hand,the pollutant removal efficiency of the system increased slightly with the increase of hydraulic load,and the effect of hydraulic load on NH₄⁺-N was relatively obvious.Compared to 0.1m3/?m2×d?,0.2m3/?m2×d?,0.3m3/?m2×d?three hydraulic loading conditions,the highest removal rates of COD and NH₄⁺-N were found under the condition of hydraulic loading of 0.2m3/?m2×d?,so in the actual project,the feedwater hydraulic load should adopt 0.2m3/?m2×d?.On the other hand,the aeration device for the removal of the system,especially the removal of nitrogen had a significant promotion.The average concentration of effluent COD and NH₄⁺-N of the system could reach Grade A standard of “Pollutant Discharge Standard of Urban Wastewater Treatment Plant”?GB18918-2002?after increasing the aeration device.Finally,the adaptability of the system to the pollution load after structural and operating parameters optimization was investigated.The experimental results showed that the removal efficiency of COD and NH₄⁺-N in low and medium concentration could be up to Class A standard of “Pollutant Discharge Standard of Urban Sewage Treatment Plant”?GB18918-2002?by modified self-purification method of capillary moistening,When the t COD influen concentration was higher than 400mg/L and NH₄⁺-N influent concentration was higher 50mg/L,the effluent concentration of the system increased slightly.The COD and NH₄⁺-N concentrations in most villages of Qihe were in low concentration or medium concentration range according to “Technical Guideline for Suburban Regional Sewage Treatment” and actual sampling monitoring data,for the high concentration rural domestic sewage,pretreatment.could be considered before the self-purification method of capillary moistening.