CH4 emission and recovery from Municipal Solid Waste in China

Methane (CH 4) is an important greenhouse gas and a major environmental pollutant, second only to carbon dioxide (CO 2) in its contribution to potential global warming. In many cases, methane emission from landfills otherwise emitted to the atmosphere can be removed and utilized, or significantly reduced in quantity by using cost effective management methods. The gas can also be used as a residential, commercial, or industrial fuel. Therefore, emission reduction strategies have the potential to become low cost, or even profitable. The annual growth rate of Municipal Solid Waste (MSW) output in China is 6.24%, with the highest levels found in South China, Southwest China and East China. Cities and towns are developing quickly in these regions. MSW output was only 76.36 Mt in 1991 and increased to 109.82 Mt in 1997, registering an average increase of 43.8%. In China, methane emission from landfills also increased from 5.88 Mt in 1991 to 8.46 Mt in 1997; so the recovery of methane from landfills is a profitable project.

高浓度生活污水处理工艺及其能源回收研究

[目的]人口增加及城镇化的发展,生活污水越来越多,连带的污染面更广,造成环境与水资源贫乏诸多问题,特别昆明地区生活污水呈现地域特点。[方法]研究水压式厌氧-自然流充氧工艺对于粪便污水的处理效果,深入分析对污染指标去除影响较大的滞留时间问题。[结果]相同组成结构的设计装置,其处理工艺不同对粪便污水处理效果也存在较大差异,4套厌氧装置下,经3级厌氧处理后相对于原水的CODCr总去除率分别为94.3%、96.1%、96.6%和97.2%。再通过好氧处理后,装置3和装置4出水中残留CODCr值分别为97.6、85.3 mg/L,达到了GB8978-1996中的一级标准,而装置2出水达到二级标准。在厌氧过程中,污染物指标CODCr去除率越高,回收能源物质CH4越多。[结论]为今后的深入研究与扩大处理系统奠定基础,并对分散式的城镇污水简易化高效处理技术的开发和进一步研究完善工程设计具有参考价值和意义。