pH和负压对生活垃圾焚烧厂渗沥液蒸发处理的影响

生活垃圾焚烧厂贮坑渗沥液含有弱电解质类的挥发性污染物,pH和压强是影响其蒸发过程中气液相分布的主要因素,实验研究了蒸发操作压强及渗沥液初始pH对蒸发冷凝液中污染物分配的影响.结果表明,操作压强16～39kPa对冷凝液的组成基本没有影响;而pH的变化则改变了挥发性弱电解质类污染物在渗沥液中的存在形态,进而显著地改变了其在冷凝液中的分配情况.当渗沥液的初始pH为5时,冷凝液主要成份为挥发性有机酸和低碳醇类物质,不含氨氮;pH＞10时,冷凝液中挥发性有机酸减少,氨氮增加.渗沥液原液经一级蒸发可显著改善其可处理性.

Impact of pH and operation pressure on evaporation treatment of leachate from refuse storage pit in municipal solid waste incineration plant

Weak electrolytes composed a great part of organic matters in the leachate from refuse storage pit (LRSP) in municipal solid waste incineration plant. Since liquid pH and operation pressure were the most important two factors related to evaporation process, the effects of these two factors on the distribution of the volatile components during the vacuum evaporation process for LRSP treatment were studied. The results showed that operation pressure had little impact on the distribution of pollutants, whereas pH of LRSP greatly affected the condensate composition by determining the form of weak electrolytes in solution. When the initial pH value of LRSP was 5, the condensate mainly contained the volatile fat acids (VFA) and low molecular weight alcohols and nearly no ammonia. The VFA concentration in the condensate decreased and ammonia nitrogen increased, when the initial pH of LRSP rose to 10. The bio-treatablilty of the LRSP was improved markedly when one-step vacuum evaporation treatment was applied.