Study On The Purification Efficiency Of Rural Sewage By Tower Sewage Ecological Treatment System

Tower of sewage ecological treatment system（TEPS,Tower ecological purification system）,is a new type of composite rural domestic sewage treatment technique,using gravity,biological,ecological energy sources such as solar energy,make full use of the mountainous natural topography,to construct the cascade purification system,cover an area of an area small and is not restricted by terrain,more suitable for rural areas and small towns.This paper takes the rural domestic sewage of Linshan Township as the research object,and carries out a one-year experimental study in Linshan Township,Yanting County,Sichuan Province,respectively discusses the tower sewage ecological treatment system at work during the stable operation of the whole system and staging of the effect of each pollutant removal efficiency and under different rainfall intensity in different concentration of pollutant load and the influence on the effect of sewage ecological treatment system purification tower.The main results and conclusions are as follows:（1）The amount of domestic sewage in this area varies significantly.In the early（7:00⁸:00）,middle（12:00¹3:00）and late（18:00¹9:00）time periods,there is a big difference in the discharge of domestic sewage.The highest value reaches 0.87m³/h,and the lowest value is 0.22m³/h.The amount of water changed greatly on the next day.The amount of domestic sewage discharged by villagers on market day ranged from 0.48m³/h to 0.81m³/h,while that on non-market day ranged from 0.26m³/h to0.58m³/h.The concentration of COD,NH₄⁺-N,TN and TP ranged from 139.42 to328.98mg/L,22.28 to 35.94mg/L,30.68 to 45.42mg/L,and 2.16 to 2.96mg/L,respectively.（2）during the normal operation of the tower sewage ecological treatment system,the purification efficiency of each pollutant is good.The average purification efficiency of COD,NH₄⁺-N,TN and TP is 69.61%,66.87%,54.29%and 72.97%,respectively.The effluent concentrations were 55.21mg/L,8.79mg/L,16mg/L,and0.7mg/L,respectively,which reached the first-class B standard of"pollutant discharge standard for urban sewage treatment plants"（GB 18918-2002）.From the perspective of the purification effect of the tower sewage ecological treatment system on each pollutant along the way,the concentration of COD,TN,NH₄⁺-N and TP gradually decreased,indicating that each filter layer contributed to the purification effect of each pollutant.However,the contribution of each section to the total purification efficiency was quite different.The purification efficiency of TN and NH₄⁺-N keeps rising,and the purification efficiency of the last segment is the highest.On the contrary,the purification efficiency of TP decreases gradually,and the purification efficiency of the last stage is the lowest.（3）During the normal operation of the tower sewage ecological treatment system,it has a good impact resistance capacity.According to the analysis of different pollution concentrations,the influent concentrations of COD,NH₄⁺-N,TN and TP were 173.27mg/L,25.33mg/L,33.9mg/L and 2.54mg/L,respectively,and the average purification efficiency was 67.7%,67.16%,55.68%and 74.48%,respectively.In the market-going period,the influent concentrations of COD,NH₄⁺-N,TN and TP were190.1mg/L,27.73mg/L,36.09mg/L and 2.64mg/L,respectively.The average purification efficiency was 70.8%,67.3%,53.27%and 72.04%,respectively.According to the analysis of rainfall intensity,the influent concentrations of COD,NH₄⁺-N,TN and TP in light rain were 182.56mg/L,25.59mg/L,34.09mg/L and2.5mg/L,respectively.The average purification efficiency was 69.84%,68.68%,56.31%and 69.31%,respectively.In moderate rain,the influent concentrations of COD,NH₄⁺-N,TN,and TP were 214.22mg/L,25.25mg/L,33.41mg/L and 2.33mg/L,respectively.The average purification efficiency was 73.07%,66.91%,56.27%and75.77%,respectively.In heavy rain,the influent concentrations of COD,NH₄⁺-N,TN,and TP were 198.43mg/L,20.27mg/L,27.95mg/L and 2.4mg/L,respectively.The average purification efficiency was 73.94%,69.85%,50.38%and 79.43%,respectively.It can be seen that different pollution concentration load and different rainfall intensity lead to a wide range of fluctuation in the influent concentration of each pollutant,but the removal rate can still remain stable and there is no major failure,which reflects the stability and high efficiency of the tower sewage ecological treatment system under different load conditions.