Experimental Study On Treatment Of Rural Domestic Sewage By Laminated Filter Box Sewage Treatment Plant

China is a country with severe drought and water shortage.At present,the shortage of water resources and the pollution of water resources are still very serious in China.With the economic and social development in rural areas,the problem of water resources in rural areas has become increasingly prominent.For a long time,the national focus of water pollution prevention and control has been on large and medium-sized cities,rural areas of water pollution control is relatively backward,resulting in China's rural areas are facing prominent contradictions between supply and demand of water resources,serious water pollution and rural domestic sewage treatment serious lag and many other problems.Therefore,it is urgent to speed up the construction of domestic sewage facilities and technology research and development in rural areas,and explore a treatment technology that matches the characteristics of rural water environment and rural water resources.In recent years,the soil infiltration system has become a hot spot of domestic sewage treatment technology in rural areas because of its low operating cost,stable effluent,low operating cost and space saving.Based on the technical principle of soil infiltration system,our research group has designed and developed an invention patent,a kind of water-type sewage treatment device with laminated filter tank.In order to improve the decontamination capacity of the plant and optimize the treatment effect of the plant,an optimum structure scheme and operation scheme were selected.The experimental study aimed to improve the treatment effect of the plant on organic pollutants,nitrogen,phosphorus and other pollutants.As well as the optimization of the operation parameters of the plant,three aspects are studied and tested.Firstly,the matrix filters used in the stacked filter tank sewage treatment plant were screened.Seven different matrix filters,zeolite,activated carbon,shale ceramsite,expanded vermiculite,fly ash ceramsite,clay ceramsite and porcelain sand ceramsite,were selected as the research objects for the static isothermal adsorption test of nitrogen and phosphorus.Its nitrogen and phosphorus adsorption properties.The results show that the adsorption capacity of the seven media is zeolite > expandedvermiculite > fly ash ceramsite > activated carbon > shale ceramsite > porcelain sand ceramsite > clay ceramsite.Among them,the adsorption capacity of zeolite is the best,and the maximum adsorption capacity is 167mg/kg.By comparing the theoretical saturated adsorption capacity and adsorption strength of phosphorus,the adsorption capacity is as follows: fly ash ceramsite > shale ceramsite > activated carbon >zeolite > expanded vermiculite > clay ceramsite > ceramic sand ceramsite.Among them,the adsorption capacity of fly ash ceramsite is the best and the maximum adsorption capacity is 985mg/kg.Based on the comprehensive consideration of nitrogen and phosphorus adsorption properties of seven matrix filters,five matrix filters,zeolite,activated carbon,shale ceramsite,fly ash ceramsite and expanded vermiculite,were selected as the matrix filters in this experiment.Secondly,this experiment optimizes the structure of the laminated filter box type sewage treatment plant.In the experiment,the simulated domestic sewage prepared by the laboratory was used as the research object.Five kinds of matrix filters,zeolite,activated carbon,shale ceramsite,fly ash ceramsite and expanded vermiculite,were mixed and filled in the ratio of 1:1:1:1:1 to investigate the effect of different layers of stacked filter tank type sewage treatment device on organic pollutants.And the removal efficiency of nitrogen and phosphorus.The test results show that the decontamination capacity of the stacked filter tank sewage treatment device with different layers is different.Among them,the removal of organic pollutants and ammonia in the device,5 and 6 layers of the device is obviously better than 3 and 4layers of the device,can meet the "Urban Sewage Treatment Plant Pollutant Discharge Standard" in the first level standard.The device with different layers has little effect on phosphorus removal.Considering comprehensively,the 5-layer device is the best choice,which not only ensures the treatment effect,but also achieves a certain degree of economy.Finally,the operation parameters of the device are optimized.In the experiment,the simulated domestic sewage was used as the experimental object,and the five-layer laminated filter tank water treatment device was selected to investigate the influence of influent mode,hydraulic load and dry-wet ratio on the decontamination andpurification capacity of the device.The experimental results show that the device has the best removal effect on organic pollutants and nitrogen and phosphorus when intermittent water intake is adopted.The average removal rates of CODcr,NH3-N,TN and TP of the effluent were 90.6%,90.41%,81.2% and 95.8% respectively.When the hydraulic load was 0.3m3 /(m2d),the average concentrations of CODcr,NH3-N,TN and TP in effluent were 33.2mg/L,6.2mg/L,9.1mg/L and 0.2mg/L,respectively,and the average removal rates were 90.0%,80.8%,78.2% and 95.8%.When the dry /wet ratio is large,the device is more conducive to the removal of CODcr and NH3-N.When the drying and wetting hours are relatively small,the TN removal effect is better.The ratio of dry to wet has no obvious effect on phosphorus removal.