EICP稳定化生活垃圾焚烧飞灰试验研究

Experimental study on EICP stabilization of MSW incineration fly ash

生活垃圾焚烧飞灰富含内源钙、呈碱性,适合采用微生物矿化(MICP)技术进行重金属稳定化处理,但MICP工程应用因环境影响显著受到限制,故开展了植物豆酶矿化技术(EICP)稳定焚烧飞灰的研究.分别从黄豆、黑豆和鹰嘴豆中提取豆酶进行活性测试、EICP处理飞灰影响因素研究及稳定化效果评价,并与MICP、EICP联合MICP处理效果对比分析.结果表明,黄豆酶和黑豆酶活性接近,远高于鹰嘴豆且高于微生物脲酶活性.豆酶活性随豆酶浓度和温度升高均增强但存在最佳活性温度,最佳活性温度随豆酶浓度升高而降低.黄豆酶和黑豆酶活性受温度影响程度不同,可据环境温度确定豆酶种类及浓度.EICP对重金属的稳定效果受豆酶浓度和活性影响明显,而养护条件对其影响较小;黄豆酶浓度为200 g·L^(-1)时,EICP对重金属固定率达85%以上,较MICP(79%以上)稳定化效果更好,拥有更大的工程应用潜力,而EICP协同MICP处理效果较差(低于50%),表明微生物与黄豆酶之间可能存在反应消耗.

Fly ash generated from municipal solid waste incineration is highly alkaline and rich in endogenous calcium,making it suitable for stabilization treatment by microbial induced calcium carbonate precipitation(MICP)technology.However,the engineering application of MICP is significantly constrained due to the stringent curing conditions required for microbial activities.Therefore,this study researched on plant legumes induced carbonate precipitation(EICP)as an alternative method for stabilizing fly ash.In the study,enzymes were extracted from soybean,black bean and chickpea,and their biochemical activity were tested.The factors affecting EICP treatment of fly ash were investigated,and its stabilization effects were assessed in comparison to MICP and EICP-MICP-combined treatments.The results revealed that soybean enzyme and black bean enzyme exhibited similarly high activities,far surpassing chickpea enzyme,and also exceeded the microbial activity of urease.Enzyme activity increased with concentration;and increased with temperature to an optimum activity temperature then decreased,while the optimum temperature decreased with the increase of concentration.The impact of temperature on the activities of soybean and black bean enzymes varied,which could direct the selection of enzyme types and concentrations according to ambient temperature.It is found that when the concentration of soybean enzyme was 200 g·L^(-1),the heavy metal fixation rate of EICP exceeded 85%,demonstrating superior heavy metal stabilization effectiveness compared to MICP(above 79%);the stabilization effectiveness of EICP was mainly affected by enzyme activity and concentrations,with curing conditions having a minor impact,indicating greater potential for engineering applications.In contrast,the EICP-MICP-combined treatment exhibited inferior stabilization effectiveness(below 50%),suggesting possible reactions between microorganisms and soybean enzymes which led to mutual consumption.