酸碱度对生活垃圾焚烧厂沥滤液蒸发处理效果的影响

Influence of pH value on efficiency of evaporation treatment of leachate from municipal solid waste incineration plant

采用蒸发法处理城市生活垃圾焚烧厂垃圾沥滤液,着重考察了不同沥滤液初始p H值对蒸发去除COD和氨氮效果的影响,并采用GC-MS对蒸发冷凝液中有机物成分进行了分析鉴定。结果表明,生活垃圾沥滤液的初始p H对冷凝液中COD、氨氮含量及有机污染物分布产生了决定性的影响。沥滤液在酸性条件下(p H≤6)蒸发,随着p H的增加,冷凝液中COD的含量线性降低,而氨氮的含量线性增加。当沥滤液的初始p H值从6增加到11,冷凝液中COD的含量呈对数函数降低,而氨氮的含量表现出显著增加趋势。从冷凝液中鉴定出38种有机污染物,多为沸点较低的醇、酸、酚和酯类。在酸性条件下(p H=3),冷凝液中挥发性有机酸和低碳醇的相对丰度接近90%。在近中性条件下(p H=6.2),冷凝液中的有机污染物以酚、酸和杂环类化合物为主。在碱性条件下(p H=11),冷凝液中酚和杂环类化合物占比较高,而酸的含量极少。

The leachate from municipal solid waste incineration plant was treated by evaporation technology. The influence of initial p H value of leachate on the removal of COD and ammonia nitrogen was investigated,and the organic pollutants distributed in the condensates were analyzed by GC-MS. The results indicated that during the distillation treatment the effects of p H on the removal rate of COD and ammonia nitrogen as well as on the distribution characteristics of the organic pollutants were much more pronounced. When the leachate was evaporated under p H≤6,COD linearly decreased,while ammonia nitrogen linearly increased with the increasing of the p H value. However,when p H value increased from 6 to 11,COD exhibited logarithmic reduction,whereas ammonia nitrogen showed the obvious increment tendency. 38 organic pollutants in the condensates were identified by GC-MS,and most of them were alcohols,acids,phenolics and esters with low boiling point. Under acidic condition( p H = 3),the relative abundance of volatile organic acids and low-carbon alcohol in condensate reached to about 90%. Under the neutral condition( p H = 6. 2),the organic pollutants in condensate were principally phenolics,acids and heterocyclic compounds. Under alkaline condition( p H = 11),the percentage of phenolics and heterocyclic compounds were much higher whereas acids were much lower in the condensate.