Basic Study On CH₄ And N₂O Release From Landfill And Methods Of Reducing Emission

Global warming has become increasingly worse mainly due to the release of greenhouse gases.Since landfills are the largest sources of anthropogenic CH₄ and N₂O emissions,the basic research on the mitigation of landfill CH₄ and N₂O emissions is of great significance.This paper makes a basic study on greenhouse gas emission reduction in municipal soild waste landfill.Based on the study on the changes of spatial and temporal on CH₄ and N₂O release,simulating the anaerobic environment in overburden layer under the condition of laboratory,we explored how the changes of external conditions（moisture content,exogenous nitrogen concentration,heavy metal,ect.）affect on CH₄ anaerobic oxidation and N₂O emission.To provide ideas for the CH₄ anaerobic oxidation and N₂O emission reduction in MSW landfill.Here are the conclusions:（1）The study MSW landfill site is the origin of CH₄ and N₂O emissions.The whole site CH₄ and N₂O emissions is 86.17,0.81 Gg×a^-1（CO₂-eq）each year.CH₄ release flux is 9.16±7.46 21287.03±128.70（mg×m-2×h-1）CH₄-C;N₂O release flux is 31.74±16.00 17089.31±7599.24（μg×m-2×h-1）N₂O-N.The average release flux of CH₄ in different five study platforms had a difference of ten times,and that of N₂O is two times.The main method to reduce greenhouse gases emission is to control CH₄ emission.The setting of LFG collection system and overburden can significantly reduce the release of greenhouse gases.（2）For CH₄ anaerobic oxidation efficiency,the critical value of exogenous NH4NO3 adjunction was 200mg/kg（NO3-concentration）,and that of KNO3 was 100mg/kg（NO3-concentration）.Low concentration can promote CH₄ anaerobic oxidation in mineralized waste,but high concentration will significantly inhibit the role.For N₂O and CO₂ emission,the critical value of exogenous NH4NO3 adjunction was 300mg/kg（NO3-concentration）,and that of KNO3 was 200mg/kg（NO3-concentration）.The critical concentration of NH4+ and NO3-will maximize the release of N₂O and CO₂.（3）Mineralized waste shows gorgeous performance on CH₄ anaerobic oxidation,which shows several times higher than other types of soil.Water content affects CH₄ anaerobic oxidation and N₂O/CO₂ emission rate by affecting the distribution of NO3-and NH4+ ions in mineralized waste.The optimum moisture content of greenhouse anaerobic abatement should be 25%³5%.Heavy metals affect denitrification by affecting the activities of denitrifying microorganisms.Heavy metals（Ba,Cu,Zn）shows a strong inhibitory effect on N₂O emission,but weak on CH₄ anaerobic oxidation.