Regularity Of Water Quality Variation In A City Sewer Networks System

As the connector between sewage discharge unit and sewage treatment plant,the collected domestic sewage has physical,chemical and biological effects on pollutants such as organic matter and nitrogen and phosphorus in the water during the transportation of the sewage network,which will lead to the change of sludge deposition and pollutant composition in the sewage network,and the operation and pollution of the maintenance work of the pipeline network caused by the change of the water quality of the sewage network.Effective operation of water treatment process has different effects.Therefore,taking the main pipe in the sewage collection area of Jinan No.1 Water Quality Purification Plant as the research object,this paper explores the temporal and spatial variation rule of the actual urban domestic sewage in the sewage pipeline and the reasons for this change rule.In this paper,through the study of the sewage pipe network from Lishan Road to Lishan North Road and from Lishan North Road to No.1 Water Quality Purification Plant,the changes of organic matter,nitrogen and phosphorus,dissolved organic matter,antibiotic resistance genes in the sewage pipe network are analyzed.The results showed that the organic matter,nitrogen and phosphorus compounds,dissolved organic matter and antibiotic resistance genes were removed to a certain extent in the urban sewage network,and the changes were mainly related to the physicochemical,biological and branch sewage influx.Concentrations of organic matter and nitrogen and phosphorus were lower in the second and third quarters,higher in the first and fourth quarters.At present,municipal pipelines in Jinan are mostly rain and sewage diversion.This seasonal change is mainly related totemperature and water consumption of residents.The temperature in the second quarter is higher,the water consumption of residents is higher,the temperature in the fourth quarter is lower,and the microbial activity in the pipeline network is relatively weak.The concentration of SS is higher in the first,second and fourth quarters.Rainfall is more in the first and second quarters.The water volume of the pipeline network increases and the flow rate becomes faster.Sewage has scouring effect on the sediments at the bottom of the pipeline network,which makes SS concentration higher.Similarly,the scouring effect of residents' water consumption on sediments is also obvious.In addition,along the pipeline network,the removal rate of total organic matter is 50.08%.The removal rates of physical deposition and microbial interpretation are 54.69% and 45.31%,respectively.The removal rate of total nitrogen is 31.22%.The removal rates of total organic matter by physical deposition and microbial degradation are 67.84% and 32.16%,respectively.But in fact,the actual urban sewage in Jinan City is complex and multifarious.Denaturation,and different concentrations of sewage,such as Heping Road,Jiefang Road,Huayuan Road and Beiyuan Road,will lead to changes in the amount of sewage and the concentration of water quality indicators in the main pipe.However,in the whole pipeline network,the change of total phosphorus is relatively small compared with other water quality concentrations,and the anoxic environment in the pipeline network is relatively stable,which has little influence on the change of total phosphorus.The change of total phosphorus in the pipeline network is mainly related to the concentration of branch sewage.Study on the water quality in different time periods within 24 hours of a day shows that the water quality of sewage pipe network fluctuates obviously in the morning,middle and late periods,and this change is mainly related to people's living habits and work habits.The sulfate concentration gradually decreases along the pipeline network.On the one hand,there are sulfate reducing bacteria and anti-sulfide bacteria in the pipeline network.Under the pipeline network environment,sulfate will be reduced to S2-.On the other hand,the competition among bacteria will be moreintense along the process.The number and bacterial content of sulfate reducing bacteria will decrease,which will lead to the decrease of sulfate concentration.In the analysis of microbial flora diversity,due to the continuous influx of sewage from trunk and branch pipes,the diversity of microbial flora gradually increases along the way,while the number of species gradually decreases due to the reduction of nutrients and species competition.