Study On MVC Evaporation Treatment Technology Of Landfill Leachate

The reduction and decontamination of municipal solid waste have become an important issue in front of the environmental circles in our country.However,the leachate generated from domestic waste has a very high concentration of pollutants and causes great impacts on water resources,soil and atmosphere,but also has a greater harm to human health.Therefore,how to deal with landfill leachate is the key to solving the future harmless treatment of garbage.At home and abroad,there are many treatment methods for landfill leachate.The Mechanical Vapor Compression?MVC?process is one of the physical and chemical treatment methods.The process has the characteristics of stable operation and strong impact resistance,and can meet various leachate water quality treatment needs.which currently gets extensive attention.The thesis is based on the leachate treatment project of Midong district MSW sanitary landfill in Urumqi,combined with the characteristics of landfill leachate water quality,this paper analyzes the characteristics of low energy evaporation+ion exchange?MVC+DI?technology and low energy evaporation technology,the mechanism of leachate treatment,process control test and production test research,and project economic benefit.By monitoring the water quality of landfill leachate for 12 consecutive months,the changes of various water quality indicators were analyzed.It was found that the water quality of landfill leachate did not change significantly with the seasons.However,with the landfill time increasing,BOD₅,COD,SS and other basic decline,ammonia nitrogen slowly increased over time,while the pH value is almost neutral and remained unchanged.In the pilot project,the leachate in the early,middle and late landfills was sampled and the evaporation test was conducted by adjusting different pH to study the evaporation regularity and the influence of COD and ammonia nitrogen.The results showed that COD and ammonia nitrogen showed higher evaporation in the first stage,slower in the middle stage and then slowly increased during the whole evaporation process of the leachate.Early COD volatilization is higher,ammonia evaporation in each period of about the same,and more than 90%of ammonia nitrogen is evaporated.Under alkaline conditions,the evaporation of COD is more than 70%under acidic conditions,especially early leachate.Organic acid and TOC evaporation increased under acidic conditions,while the amount of alcohol evaporation is almost not by influenced acid-base.In the Pilot test,the MVC evaporation equipment installed in this project was used to explore the effect of pilot test.The scale of pilot test was 50 t/d.The results showed that the effluent pH of the leachate basically did not change with the running time,but the SS generally showed a downward trend,the COD was not detected,the effect of ammonia nitrogen removal was not obvious,and the ammonia nitrogen was effectively removed after the condensate effluent was treated by ion exchange treatment.The indicators of effluent meet the national emission standards.The operation cost of MVC evaporation system is about 65 yuan/t under pilot-scale conditions,and the comprehensive operation cost is high.However,the MVC+DI technology shows the characteristics of large project investment and moderate energy consumption in practical application after the project is put into production.The actual operation cost of MVC evaporation system is lower than that of pilot scale,which has good economic benefits.