Monitoring And Analysis Of Water Quality Characteristics Of Rainwater And Surface Runoff In Anqing City

With the rapid development of China's economy and the continuous expansion of urbanization,the shortage of resources and urban ecological problems in many areas of China have become increasingly prominent.The shortage of water resources has become the most prominent problem in the process of urban development in China.The exploitation of groundwater and the increase in the area of impervious floors have increased the crisis of ground subsidence.Rainwater is one of the most important sources of groundwater supply and an important way to resolve the contradiction between water supply and demand.Water quality-type water shortage caused by current point source and non-point source pollution is one of the main causes of water shortage.Non-point source pollution caused by stormwater runoff has become one of the important reasons for the deterioration of water environment.This paper takes Anqing city as an example to sample and monitor the natural rainfall and different underlying surface Rain Water in industrial area and cultural and educational district from 2017 to 2019,and makes a comprehensive analysis.Standard method was used to measure the conductivity of pH,NH₃-N,TN,TP and COD;and flame atomic absorption spectrophotometry was used to determine the Cu,Mn,Fe,Zn;graphite furnace atomic absorption spectrophotometry?GFAAS?was used to determine metal ion Pd,Cd;and ion chromatography was used to determine anionic and cationic ions.Determination of cyanide by pyridine-barbituric acid spectrophotometry.Comparing the data results with the surface water environmental quality standards,the following conclusions are drawn:?1?Analysis of natural rainfall and rainwater quality data in different regions of Anqing City for three years shows that the natural rainwater quality is better.The pH of the cultural and educational areas and the industrial area are between 6 and 7.There is no acid rain?pH<5.6?,and the conductivity fluctuates widely.The natural rainfall rainwater COD,NH₃-N,TN and TP do not exceed the Class V standard of GB3838-2002 Surface Water Environmental Quality Standard.Rainwater enters the surface water body and has less impact on water quality.In the three years of monitoring data from 2017 to 2019,we can see that the COD,TP,and TN monitoring data are decreasing and the indicators monitored show that the industrial area is higher than the cultural and educational area.The results of the study indicate that the industrial zone may be affected by the environmental impact of the plant in the process of refining and producing products,and it will also be affected by the relatively large traffic volume and human flow in the vicinity of the industrial zone.The cultural and educational district is located in the suburbs.The flow of people and traffic is relatively small.The pollutants discharged to the environment are relatively small.At the same time,due to the large amount of vegetation and certain purification capacity,the monitoring indicators have certain differences.Natural precipitation is also affected by rainfall characteristics.Rainfall can promote the water quality of runoff rainwater.For example,when rainfall increases,the runoff water quality is better.However,the time between the two adjacent rains will cause the runoff rainwater quality to deteriorate.?2?The water quality indicators of different underlying surfaces in the cultural and educational areas of Anqing City,COD,ammonia nitrogen and total phosphorus are lower than the national surface water environmental quality standard class V;cyanide is lower than the national surface water environmental quality standard class I;industrial area The total nitrogen concentration is slightly higher than the national surface water environmental quality standard category V;heavy metals manganese and cadmium are below the detection limit.Other heavy metals are within the Class II standard of GB3838-2002 Surface Water Environmental Quality Standard;the concentration of anion and cation in different underlying surface runoff water quality is as follows:the proportion of fluoride ion and chloride ion in anion is less than sulfate ion and Nitrate ions,the proportion of calcium ions and potassium ions in the cation is greater than that of sodium ions and ammonium ions.The research results show that the types of pollutants on the road and parking lot are more than the roof,which may be due to the gas and some pollutants generated by the factory production process,as well as the influence of vehicle flow and automobile exhaust.?3?Through the precipitation and adsorption treatment of surface runoff,the precipitation experiment time is 15 min,30 min,60 min,120 min.The experimental results show that the longer the time,the better the sedimentation effect,but the removal effect is most obvious at30 min.Two kinds of adsorbents,activated carbon and artificial zeolite,were selected in the adsorption experiment.The dosage was 2.5g,5.0g,7.5g,10.0g.The results showed that the adsorption effect of artificial zeolite was better,and both activated carbon and artificial zeolite increased with the dosage of activated carbon and artificial zeolite increased.The effect is better.The optimum input amount of activated carbon was 5.0 g,and the input amount of artificial zeolite was 7.5 g.The results show that precipitation and adsorption have certain effects on rainwater treatmentand,the treated rainwater can be utilized with reference to the water quality requirements and standards for rainwater reuse.Rainwater runoff on the underlying surface is not only affected by rainfall and drying time before rain,but also by the type of underlying surface.