Monitoring and Evaluation of Agricultural Non-point Source Pollution Control Effect:Taking Yi'an District,Tongling City,Anhui Province as an Example
Monitoring and evaluation of agricultural non-point source pollution control effect is of great significance to measure the implementation effect of agricultural non-point source pollution and control it in small watershed.Taking agricultural non-point source pollution control project in Yi'an District,Tongling City,Anhui Province as an example,according to the monitoring principle of"source of pollution-transport route-receiving water area",this paper determined the monitoring points,frequencies and indicators of each treatment project,used single factor index method and comprehensive pollution index method to analyze and evaluate the implementation effect of each treatment project.The results showed that TN was the main pollutant of farmland non-point source pollution.In the early stage of treatment,the multiple of exceeding the standard(Class Ⅲ of surface water)reached 1.58.After engineering treatment,the pattern of pollutant reduction concentration was NH4+-N>TN>COD>TP.In the control project of livestock and poultry breeding pollution,the removal effect of pollutants after each process was anaerobic returning process>ectopic fermentation process>oxidation pond process.The removal rate of pollutants in anaerobic returning process and ectopic fermentation process was higher than that in early stage,oxidation pond process was on the contrary.The comprehensive COD removal rates of the three processes were 44.43%,20.91%and 33.70%,respectively.The removal rate of NH4-N in anaerobic field returning process was 69.66%,which was the highest.Suspended solids(SS)was the pollution factor with the highest pollutant removal rate in ectopic fermentation process,and its removal rate was 55.44%.The comprehensive TP removal rate of oxidation pond process was also the highest,which was 74.72%.Aquaculture pollution control project adopted the"three pools and two dams"process,and the removal sequence of each pollutant was TP>TN>SS.Based on the comprehensive pollution index evaluation of entropy weight,this paper found that the agricultural non-point source pollution project in the study area was in the polluted state before treatment,while the evaluation result reached the qualified state after treatment.This study can provide reference for methods of monitoring and evaluation of agricultural non-point source pollution control effect in the Yangtze River basin.
agricultural non-point source pollutionthe Yangtze River basinenvironmental monitoringcomprehensive pollution index methodeffect evaluation