生物反应器填埋条件下垃圾生物质组分的初期降解规律

在经甲烷化填埋层渗滤后的渗滤液循环回灌的新鲜垃圾填埋层内,以生物质分类表征为基础,分析了新鲜垃圾填埋层内固相各生物质组分（总糖、蛋白质、脂肪、纤维素和木质素）的初期降解规律.结果表明,垃圾中原有总糖组分和蛋白质的快速水解发酵是新鲜垃圾填埋后产生高有机质浓度渗滤液的主要机制;脂肪和纤维素的降解产物不是填埋初期高有机质浓度渗滤液的主要来源;纤维素是填埋层稳定产甲烷阶段的主要碳源,其水解速率可能是甲烷化过程的限速步骤;纤维素/木质素之质量比可作为指示填埋垃圾稳定化的指标.各生物质组分的初期降解速率常数均在0.01至0.1之间,而填埋气体中甲烷体积分数在60d内达到45%.食品垃圾组分富集的生活垃圾,应用生物反应器填埋技术时,必须具备足够的降解容量以代谢填埋初期固相中总糖和蛋白质快速水解产生的酸性液相产物.

Biomass compositions fermentation in initial stage of fresh municipal solid waste degradation in bioreactor landfill

Lab-scale simulated fresh MSW bioreactor landfill columns, recirculated with the leachate from stabilized landfill layer, were setup. Sugar, protein, lipid, cellulose and lignin fermentation in the fresh MSW landfill layer were studied. The results indicated that sugar and protein fermentation caused high concentrations of organic carbon in the leachate during the initial stage of waste degradation. However, the degradation of lipid and cellulose during the initial stage was much slower, and they were not the key compositions causing heavy leachate pollution. Cellulose was the principle source of carbon for the methanogenefic process, and the hydrolysis rate of cellulose was the limiting factor for waste degradation and methanogenesis. The hydrolysis rate constants for all the compositions were between 0.01 to 0.1 ; the methane volume fraction found in the landfill gas reached 45% in 65 days. Sufficient capacity for degradation of acidic products from sugar and protein fermentation should be supplied when the bioreactor landfill technology is applied as the MSW characterized with high food waste content.