The Combined Process Of SBR And Constructed Wetland System For Decentralized Rural Domestic Sewage

At this stage,the treatment process for decentralized rural sewage is still in its infancy,and the treatment process for the water quality and water characteristics of decentralized rural sewage is not in place.In order to solve the problems such as the high dispersion degree of dispersed rural sewage,the large fluctuation of water quality and the serious pollution of nitrogen and phosphorus,this paper adopts the combination process of SBR-artificial wetland not only combines their respective advantages,but also makes up for their respective shortcomings,studies the law of pollutant degradation and organic degradation of organic matter,investigates the effect of sepsis,aeration time,water exchange ratio and artificial wetland intake organic load on the effect of combining the process.It is determined that the optimal process parameters for the combination process to achieve sewage discharge while reducing energy consumption are determined.This combination of technology in decentralized rural sewage treatment to provide theoretical and technical support.The findings are as follows:（1）The SBR-artificial wetland combined process solves the difficulty of intermittent drainage in rural areas and has a good removal effect on rural domestic sewage.During stable operation,the effluent concentrations of COD,NH₃-N,TN,and TP are 29.29,1.0,16.71,and0.67mg/L,respectively.With removal rates of 85.56%,97.76%,68.84%,and 85.13%,respectively.The combined process effluent COD and NH₃-N reached the level A standard of Pollutant Discharge from Urban Waste Water Treatment Plants（GB18918-2002）,TN,TP Reached the Grade B standard of"Emission of Pollutants from Urban Sewage Treatment Plants"（GB18918-2002）.The optimal operating parameters of the combined process are SBR reactor intermittent aeration,aeration for 3 hours,water exchange ratio of 1:1,and the organic load of artificial wetland water intake is 20-40(g·m^-3·d^-1).（2）Through the analysis of pollutant removal rules and kinetics in the SBR reactor,it is concluded that the reactor has a good treatment effect on COD and NH₃-N.The removal rate can reach 85%and 99%when aerated for 5 hours.It meets GB18918-2002-Class A standard,and also has a certain removal effect on TN and TP.The removal rate can reach 45%and 68%.DO content,ORP and ph value can better reflect the degradation degree of pollutants in the reaction system,the growth period of microorganisms,and environmental alkalinity.At the same time,the DO content and ORP value can also adjust the aeration in real time to Reduce reflected energy consumption.Within the experimental COD range,the SBR reactor follows the first-order reaction kinetics equation.The correlation is particularly good through fitting,and the correlation coefficient reaches 0.963.（3）Experiments show that continuous aeration is beneficial to the removal of COD and NH₃-N in the SBR reactor by changing the aeration method in the SBR reactor,but intermittent aeration improves the removal effect of TN in the reactor,and the removal rate can be improved.About 11.8%,the reactor uses intermittent aeration.（4）Experiments by changing the aeration time of the SBR reactor showed that when the aeration time was 2h and 3h,all types of pollutants did not meet the discharge standards.When the aeration time was 4h,the effluent COD,NH₃-N,TN,TP The concentrations were37.41,2.58,43.70 and 2.98 mg/L,and COD and NH₃-N all reached Level A standard of the Pollutant Discharge Standard for Urban Sewage Treatment Plants（GB18918-2002）.At the same time,TN and TP also had certain removal effects.（5）The experiment results show that the change of the water exchange ratio mainly affects the removal effect of COD,TN,and TP in the SBR reactor,and has little effect on NH₃-N.The removal rate of TN and TP is significantly higher under the 1:1 water exchange ratio.（6）When the organic load of the artificial wetland is less than 20(g·m^-3·d^-1),the effluent COD,NH₃-N,TN,and TP removal rates can reach 10.73%,68.56%,18.29%,and 72.80%,of which the effluent CODcr,NH₃-N,and TN can reach The level A standard of the Pollutant Discharge Standard of Urban Sewage Treatment Plants（GB18918-2002）,TP can reach the level B standard of the Pollutant Discharge Standard of Urban Sewage Treatment Plants.