| The safety of drinking water and drinking water sources is very important for national economy and people's livelihood.This article research theproblems of pesticide pollution of drinking water in Guiyangby source control technologies.Selecting Hongfeng Lake as the object,the pollution of the riversinflow the Hongfeng Lake was studied through field sampling and detection.The pollutant distribution map was drawn and analyzed according to the type,time and place of pesticide pollutants.Here,fenpropathrin and triadimefon were selected as the main research pesticides,and Pingzhai Village was selected as the main research site.According to the characteristics of pesticide pollution in dry soil of Pingzhai Village,mixing spent mushroom substrate(SMS)and soil was used to control the source pollution.Experimentresults show that the SMS mix soil technology has obvious effect on reducing the content of two pesticides in soil leachate.Among several options,Pleurotus eryngii SMSshow the best removal effect,The relative removal rates of fenpropathrin and triadimefon are 41.4% and 79.1%,respectively.Pleurotus eryngii SMS was selected as the main object.Designing experiments to study the effects of different factors on leachate pesticide content,results are summarized as follows:(1)For the using amount of SMS,the relative removal rates of fenpropathrin and triadimefon were 80% and 79.5%,respectively,when the proportion of SMS was 10% of the soil proportion,and the removal effect was similar to that of the 30% group.When the proportion is 50%,the relative removal rates of the two are 83% and 87%,respectively.The best ratio for the experiment is 50%,and the best ratio for practical applications is 10%.(2)When the reaction time of mixed soil and pesticide is longer than 6 days,fenpropathrin relative removal rate 78%,relative triadimefon about 85.1% removal.The control effect is better when the reaction time of mixed soil and pesticide is more than 6 days.(3)In consideration of the co-effect of Pleurotus eryngii SMS and other SMS,the relative removal rates of fenpropathrin and triadimefon were 85% and 95% when using Pleurotus eryngii SMScoupled with Oyster mushroom SMS,respectively,which is better than that of using sole Pleurotus eryngii SMS.(4)For the dosage of pesticides,when the concentration of the drug gradually decrease,the relative removal rates of the two pesticides gradually increase.Asthe ratio of pesticide to solvent is 1:2500,the relative removal rates of the two pesticides were 83% and 96%,respectively.Scientific use of low-concentration pesticide solution is beneficial to the control of pesticide pollution.In view of the pesticide pollution caused by farmland reclamation in the paddy fields of Pingzhai Village,the "ecological pond + constructed wetland" system was selected to control the source pollution.Five groups of experiments were designed to study the effect of hydraulic retention time(HRT),plant type,whether using SMS in the soil layer,and pesticide contamination load on the removal rate.The results are as follows:(1)Each group of systems can achieve their best removal efficiency after 2days.The optimal HRT for the “ecological pond + constructed wetland” system is 2days.(2)System A(planted ryegrass in wetlands)has better removal rate of triadimefon,while System B(planted canna in wetland)has better removal rate of fenpropathrin.In actual use,it is necessary to selectsuitable plant species according to the type of pollutants.(3)When using SMSin soil layer,the removal rate increase by about 10% compared with the control group.This measure can significantly improve the control effect of the “ecological pond + constructed wetland” system on pesticide pollution.(4)The “ecological pond + constructed wetland” system has a certain ability to resist impact.When the pollution load of pesticides changes,the effluent water quality is basically stable.System A is slightly more impact resistant than System B.In order to improve the source control technology system,the following complementary recommendations and measures are proposed in terms of regulations,policies,production structure,agricultural technology,and promotion management. |
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