生活垃圾渗滤液膜滤浓缩液的蒸发特性

Evaporation Characteristics of Concentrate from Membrane Filtration of Domestic Landfill Leachate

MBR+膜法是生活垃圾渗滤液的主流处理工艺之一,但在处理过程中会产生20%~30%的膜滤浓缩液,其盐分及不可生物降解有机物含量均较高,目前主要采用蒸发技术进行处理。利用模拟蒸发装置处理湖南某生活垃圾填埋场的膜滤浓缩液,考察不同预处理方式及蒸发压力下沸点变化情况及超高倍浓缩后釜底液特性。结果表明,在相同条件下,负压蒸发沸点温度显著低于常压蒸发,但沸点温升均高于常压蒸发。预处理方式对不同压力下蒸发的初始沸点温升(<2℃)及常压蒸发下的终点沸点温升(7~8℃)无显著影响,但调酸及除有机物可降低负压蒸发终点沸点温升5~7℃。经20倍负压蒸发浓缩后,釜底液无机成分主要为钠/钾盐,有机成分主要为富里酸类。

The process consisting of MBR and membrane filtration is one of the mainstream treatment processes for domestic landfill leachate.During the treatment process,20%to 30%of membrane filtration concentrate is generated,which contains a high level of salt and non-biodegradable organic matters.Currently,evaporation is predominantly employed for its treatment.A simulated evaporation apparatus was employed to handle the membrane filtration concentrate from a domestic landfill in Hunan Province.The variations of boiling point under diverse pretreatment approaches and evaporation pressures as well as the features of the bottom residue after ultra-high concentration were examined.Under the identical conditions,the boiling point temperature of negative pressure evaporation was conspicuously lower than that of atmospheric pressure evaporation,yet the increase in boiling point temperature was higher than that of the atmospheric pressure evaporation.The pretreatment methods had no substantial impact on the increase in the initial boiling point rise(less than 2℃)and the increase in the endpoint boiling point rise(7-8℃)under different pressure evaporation.However,acid regulation and the removal of organic matters could reduce the endpoint boiling point rise of negative pressure evaporation by 5-7℃.After undergoing negative pressure evaporation and concentration for 20 times,the inorganic component of the bottom residue mainly consisted of sodium/potassium salts, and the organic component mainly comprised fulvic acid.