Micro-nano Aeration Method On The Treatment Of Black And Smelly River In Shanghai Suburb

Background:The suburbs of Shanghai are located on the front edge of the Yangtze River Delta,facing the East China Sea to the south,Jiangsu and Zhejiang provinces to the West,and the estuary of the Yangtze River to the north.The suburbs include Minhang District,Baoshan District,Jiading District,Qingpu District,Songjiang District and Jinshan District,with a registered population of6.284 million,accounting for 46.8 percent of the city’s total population.Because of the huge industrial system,high population density,a large number of industrial,agricultural,domestic sewage discharge at will,leading to large-scale water pollution,causing Algal Bloom,the formation of black and odorous water,seriously affecting the urban living environment and image.The ecological system structure of the urban water body is seriously out of balance,which not only affects the image of the urban sanitation civilization,but also brings the extremely uncomfortable sensory experience to the masses More serious is easy to cause sudden water pollution and lead to epidemic diseases and malignant tumors,causing great negative impact on the physical and mental health of the people.Objective:This topic on the basis of predecessors’work,through a large number of experiments and field survey,the study of micro-nano aeration technology of black smelly river governance effect and its mechanism,and carries on the qualitative quantitative analysis,find the aeration mode,aeration time and the pollutant removal rate,the relationship between aims to seek a highly efficient low consumption of aeration mode,for the promotion of micro-nano governance black smelly river aeration method to provide the reference.Methods:In this study,the smell-black water body of small and medium-sized rivers in the suburbs of Shanghai was selected as the experimental research object.p H,chemical oxygen demand(COD),dissolved oxygen(DO),ammonia nitrogen,total phosphorus(TP)and total nitrogen(TN)were selected as the key indicators for the evaluation of smell-black water body.On the basis of confirming that micro-nano aeration is the most effective method to purify black-odor water body,the effect of micro-nano intermittent aeration on improving black-odor water body was studied.Finally,the experience of the experiment was applied to the governance of Yao Bang river area in the suburb of Shanghai,and the public satisfaction survey was conducted to evaluate the effectiveness of black and smelly water governance.Spss was used to analyze and evaluate the effect of micro-nano aeration on improving black and smelly water.Results:1.After 18-hour test,the dissolved oxygen(DO)was rapidly raised from the initial value of1.2mg/L to 5.2mg/L by micro-nano aeration.The dissolved oxygen content in the water was rich and the water body reached the self-purification level.It shows that the effect of using micro-nano aeration is good.2.Using micro-nano aeration method to improve dissolved oxygen(DO)in water body for 6hours can reach the increase value after 18 hours using ordinary aeration method,saving nearly 1/3of the time;Using micro-nano aeration method to remove chemical oxygen demand(COD)after10 hours can reach the common aeration method after 18 hours of the value;The ammonia nitrogen micro-nano aeration method can reduce the value to 18 hours after the normal aeration method.The removal of total nitrogen(TN)micro-nano aeration method also saves 1/2 time compared with the ordinary aeration method.This shows that micro-nano aeration is economical.3.The removal rates of COD,ammonia nitrogen and total nitrogen(TN)in black stink water were 71.9%,77.5%and 67.0%respectively by micro-nano aeration,and the removal effect was better than that of ordinary aeration group.It can be seen that the degradation efficiency and removal rate of pollutants in water by using micro-nano aeration method are significantly higher than that by common aeration method.4.Using micro-nano intermittent aeration,after 8 hours of operation,Dissolved oxygen DO increased 2.68 times,The removal rates of ammonia nitrogen,Chemical oxygen demand phosphorus,total phosphorus and total nitrogen were 61%,53.2%,30.5%and 62.7%respectively.The removal effect is better than the continuous aeration of the water body,and it is more economical.In the pilot experiment of micro-nano Aeration treatment of Yao Bang River area,the instrument runs in 8 hours per day,and the cost of electricity and manpower is greatly reduced than that of continuous operation.5.At the same time,based on the impact of black and smelly river water on the health of the surrounding population and the satisfaction degree after remediation,a personnel questionnaire survey was conducted,and spss analysis was adopted.Chi-square test was conducted on the understanding degree of the remediation project and the satisfaction degree after remediation.The P value obtained was 0.008(P<0.05).This shows that residents who know and know the entire process of the remediation project hold a positive attitude towards the effect of the black and smelly river water remediation project.With the completion of the remediation project,According to the analysis of the satisfaction degree of remediation and the influence of surrounding residents on their own health after the remediation,the P value is 0.001(P<0.05),which indicates that after the completion of the remediation project,the satisfaction degree of surrounding residents is relatively high and their physical and mental health has also been improved to some extent.To further verify the beneficial effects of micro-nano aeration method on the health of the population.This paper provides a reference for the treatment of black and smelly river water by micro-nano aeration in small and medium-sized rivers in similar areas.Conclusion:Micro-nano aeration is a new type of water aeration and oxygenation technology,which has obvious advantages of low investment and high efficiency in the process of black and smelly river water treatment.Two micro-nano aerators are used in the 4000m~2water area,which are turned on for 8 hours per day and run for 22 days.The average power consumption per cubic meter per hour per day is 0.07 yuan/m~3/h.Micro-nano aeration can make the water quality of Yaobang River reach the"surface water environmental standards"(GB3838-2002)Ⅴclass water quality standards,Normal aeration takes a long time,Bubbles stay in water for a short time,The rising efficiency of dissolved oxygen(DO)is not high,and the black and smelly water body cannot achieve a good self-purification effect within a period of time,and the water quality of the black and smelly river cannot be improved.The details are as follows:1.the effect of micro and nano aeration in treating black and smelly river water is better than that of ordinary aeration,the period of w quality restoratiateron is short,and the cost is saved.The aeration capacity,the utilization rate of oxygen and the degradation efficiency and removal rate of pollutants in water by micro-nano aeration are obviously higher than that by ordinary aeration.2.The micro-nano aeration method is applied to control the black and smelly river water of Yaobang River in Jiading District of Shanghai.The micro-nano intermittent aeration method is adopted to run the aerator for 8 hours a day,which is better than continuous aeration in economic cost.To monitor the quality of water for 22 days,found that the overall ecological restoration of water and water self-purification capacity recovery effect is good,the water quality to environmentalⅤclass water quality standard and stability,the governance project implementation effect is good.