Classification And Key Influencing Factors Of Apparent Pollution In Urban Water

Up to now,the main function of urban water bodies is landscape function,but due to the influence of external pollutants,the landscape function of urban water bodies has gradually disappeared.Urban water bodies can no longer satisfy the effects of pleasant people,and urban water bodies are affected by external pollutants.The phenomenon that causes the sensory discomfort of the human body is the apparent pollution of the water body.The existence of apparent pollution in urban water bodies not only causes serious problems in the maintenance of urban living environment,but also seriously affects the healthy development of urban ecological environment.This issue has attracted the attention of government departments.Restoring the urban water landscape function has become the primary goal of urban water pollution control,and the existing water quality assessment methods and evaluation methods for apparently polluted extreme water bodies cannot meet the needs of people to evaluate the apparent quality of water bodies.In order to make up for the shortcomings and limitations of current urban water evaluation methods and to meet the actual needs of water pollution assessment,the research team constructed a characterization method,the apparent pollution index method(SPI),which was adopted in 2015.It is included in the “Guidelines for the Remediation of Urban Black and Stinky Waters”,but this method is only a means of characterization,and it is impossible to analyze the causes of apparently polluted water bodies,and it cannot provide guidance for the determination of prevention and treatment technical schemes for apparently polluted water bodies.The research object is the water body that meets the research objectives in the urban water body of Suzhou.Through the analysis of the genesis of different apparent polluted water bodies,the characteristic indicators or characteristic values of different apparent polluted water bodies are screened out,and the apparent pollution classification method is constructed.The influencing factor of the indicator or eigenvalue.The research results can provide guidance for the prevention strategies and restoration schemes of apparently polluted water bodies,and propose different targeted pollution types for targeted treatment programs.This study mainly got the following conclusions:(1)Definition and distinct characteristics of water bodies with different apparent pollution types were defined: organic dominant type of apparently polluted water body,the main pollutants are organic matter,including black odor phenomenon or water bloom phenomenon caused by algae transitional reproduction,water body appears black,dark green;Inorganic dominant type of apparently polluted water is mainly caused by inorganic substances(inorganic particles such as sediment),the turbidity is high,and the water body is mostly yellow,khaki;The nutrient-oriented apparent polluted water body is mainly caused by inorganic nutrients(N,P,etc.)in the water body.The water body is good in appearance,showing clear,no obvious suspended matter,green and so on;Mixed superficially polluted water bodies are between the above-mentioned apparent pollution types,caused by inorganic substances,organic substances,etc.,and have the characteristics of shifting to a certain type of organic dominant,inorganic dominant,and nutrient-dominated types,the water body is mostly yellow-green and gray.(2)By monitoring the water quality indicators of the rivers in Suzhou,and using statistical methods to summarize the data,construct an apparent pollution classification method,and based on the results of exclusive verification,delineate the priority order of different apparent polluted water bodies,inorganic dominant Type>organic dominant type> nutrition-led>mixed type,finally determined that the organic dominant type(black odor)apparent polluted water body characteristic index is redox potential(ORP),the determination condition is ORP<0 mv;organic dominant type(water bloom)appearance The characteristic index of polluted water is the ratio of dissolved oxygen to saturated dissolved oxygen(DO/DOs)and chlorophyll a.The determination conditions are DO/DOs>1 and Chla>50 μg/L;the inorganic dominant type of apparent polluted water is characterized by high The ratio of manganate index to turbidity(Im/Tur)is determined by Im/Tur<0.08 mg/L/NTU;the dominant indicator of nutrient-oriented apparent polluted water is turbidity(Tur)and chlorophyll a.The judgment condition is Tur<15 NTU and Chla<50 μg/L.The verification of the indicator system confirms the accuracy of the selected characteristic index or eigenvalue of the method,which further enhances the feasibility and rationality of the apparent pollution classification method.(3)The method of correlation analysis and stepwise regression analysis is used to analyze the key factors of the externally affected water body characteristic index orcharacteristic value: for the organic dominant type of polluted water body,the water caused by the black body odor phenomenon and the algae transitional breeding The Hua phenomenon is analyzed separately.The results show that the key influencing factors of organically dominant(black odor)apparent polluted water are dissolved oxygen and permanganate index;the key influence factors of organic dominant(water bloom)apparent polluted water are water body.Temperature and dissolved oxygen;for inorganically dominant apparently polluted water bodies,the key influence factors of inorganic dominant type of polluted water are permanganate index and turbidity,and the disturbance effect of ships to water bodies cannot be ignored;Apparently polluted water,total phosphorus,permanganate index,temperature and ammonia nitrogen are key influence factors for nutrient-dominated apparently polluted water bodies,at the same time,some preventive measures for different apparent pollution types of water bodies are put forward.