Landfill Gas Status And Its Risk Assessment In Lhasa Municipal Landfill Site

With the improvement of people's living quality,the yield of municipal solid waste(MSW)will continue to increase,which led the disposal of household waste becoming the focus of environmental prevention and control.At present,the most direct and simple way of centralized disposal of MSW in China is sanitary landfill,which has advantages such as mature technology and low treatment cost.At the same time,the secondary pollution problem also caused a greater impact on the surrounding residents.Lhasa MSW landfill site is one of the regular sites for solid waste treatment and disposal in Lhasa and its surrounding areas,the landfill gas generated is inevitable secondary pollution,which is the focus of the prevention and control of landfill pollution.However,at present,there are few studies on monitoring and evaluation of landfill gas generation in Lhasa MSW landfill site,and there is a lack of data support for pollution prevention and control.In this study,we adopted the national standard "discharge standard of odor pollutants"(GB14554-93),the current situation of odor emission from the landfill in Lhasa was monitored,the single-factor index method and the comprehensive index method were used for analysis and evaluation.At the same time,this study analyzed the concentration and contribution rate of odor gas from the pollution source of the landfill.Moreover,the forecast of the yield of methane gas from the landfill was studied,while analysis of the emission reduction potential of greenhouse gas from the landfill was also carried out,so as to provide reference for the construction and management of relevant projects.The main research results are as follows:1.Concentration of 9 odors(including ammonia(NH3),trimethylamine(C3H9N),hydrogen sulfide(H2S),methyl mercaptan sulfur(CH3SH),methyl ether(CH3)2 s,dimethyl disulfide ether(C2H6S2),carbon disulfide(CS2),styrene(C8H8))of the brand of Lhasa landfill and chosen sensitive spots was monitored.The results showed that the hydrogen sulfide concentration in all the sampling sites did not exceed the value proposed by national standard "odorous pollutants discharge standard"(GB14554-93),while the other odors were negative;2.The theoretical odor concentration,odor intensity and contribution rate of pollution sources were calculated,showed that the odor concentration was the highest At 14:00,and the sulfur compounds including trimethylamine and hydrogen sulfide made the largest contribution to the odor concentration.The stench intensity of hydrogen sulfide reaches the level of "obvious odor" in pollution sources,while the odor intensity is large,requiring special attention to the generation of hydrogen sulfide.3.The prediction of the methane yield in Lhasa landfill was analyzed,the results showed that methane yield is definitely low.The analysis of the methane emission reduction approaches from Lhasa landfill site was studied,and the results showed that the cumulative economic benefits of electricity generation from landfill gas in Lhasa landfill site was pretty low.Considering the high cost of equipment,landfill gas methane power generation is not economically feasible.We suggested that the methane gas discharged from the landfill in Lhasa should be treated with torch combustion to prevent the pollution of the surrounding environment.