北京市生活垃圾处理的温室气体排放变化分析

文章从城市垃圾处理与节能减排之间关系的角度,分析研究了北京市2001～2007年生活垃圾卫生填埋、堆肥和焚烧发展过程中直接和间接的温室气体排放量变化,结果表明,随着生活垃圾产生量的增加和物理组成的变化,北京市生活垃圾处理引起的温室气体排放急剧增多,总排放量从2001年约363万tCO2当量增加到2007年1157万t左右。目前卫生填埋、堆肥和焚烧三种方法每处理1t垃圾的单位排放量分别为2.1t、0.4t和2.0tCO2当量。虽然堆肥具有相对低的单位排放量,但由于市场等方面的原因,堆肥在北京生活垃圾处理中的比重并不大,2007年处理的垃圾量不到无害化总处理量的7%。2007年填埋产生CH4总量约48万t,若50%回收利用,其发热量相当于约40万t管道煤气,具有很大的节能减排潜力。焚烧垃圾进行供热或发电的技术在国内外正蓬勃发展,也是节能减排的有效途径。而加强垃圾回收与分类是从源头减少垃圾,实现节能减排的最好方法。

Greenhouse Gas Emission from Municipal Solid Waste Treatment in Beijing

To evaluate greenhouse gas (GHG) emission reduction associated with municipal solid waste (MSW) treatment/ disposal,this article analyzes the quantities of both direct and indirect GHG emissions from different solid waste treatment/ disposal methods,i.e.,sanitary landfill,composting and incineration based on the survey in Beijing from 2001 -2007,showing that GHG emissions from the waste disposal have soared over the last few years. The total amount of GHG emissions rose from ca. 3.63 million tons of CO2 equivalents in the year 2001 to ca. 11.57 millon tons in 2007. The emission rates for the three different approaches were compared in terms of CO2 equivalent per ton of MSW,which showed that emission rate of composting was the lowest,but its application in Beijing remains at a low level,accounting for less than 7% of the total MSW treated in 2007. On the other hand,landfill in the city generated 0.48 million tons of CH4,which was equivalent to ca. 0.40 million tons of town gas if half of the CH4 could be collected and recycled; and heat and electricity could be recycled from MSW incineration. However,the best approach is MSW reduction from the very beginning from the sources such as household waste sorting and recycling.