有机生活垃圾堆肥中物质组分减量差异及变化规律

以农村有机生活垃圾的主要组成——餐厨垃圾和作物秸秆为处理对象,分类表征不同好氧堆肥条件下餐厨-稻草总物质、干物质及主要组成元素的减量差异及其在不同时间的变化规律,进一步借助冗余分析(Redundancy analysis,RDA)明确主要堆肥过程因子对物质组分代谢的影响程度。结果表明:本试验中4个堆肥处理的总物质减量效果为单一通风组通风+菌剂组对照组通风+菌剂+纤维素降解菌组,对于带有辅助通风设备的处理而言,7~13 d是垃圾减量化的主要时间区段。不同处理的水分去除方式不同,菌剂接种可促进水分以蒸发形式去除。不同处理组下干物质的元素损耗具有倾向性,通风+菌剂+纤维素降解菌组中碳素和氢素的损失量占干物质损失量的百分比依次高于通风+菌剂组、单一通风组和对照组,氧素的损失量占干物质损失量的百分比则正好相反。菌剂接种处理的碳素消耗主要发生在0~13 d,约占碳素总消耗量的60%以上。冗余分析结果指出温度和细菌数量是影响物质和元素去除的主导因素,其中温度与不同时间区段垃圾减量能力和水分损失量呈最大正相关,而细菌数量、放线菌数量和真菌数量分别与区段干物质损失、氢素损失及氧素损失呈最大正相关。以上研究结果可为有机垃圾堆肥过程中渗滤液排放、物质损失控制和垃圾生态代谢研究提供一定的指导。

Differential Reduction of Different Components of Domestic Organic Wastes During Composting Process

Kitchen wastes and straw represent major percentages in domestic wastes generated in the rural areas. A co-composting experiment of kitchen wastes and rice straw was performed under different conditions to investigate reduction behaviors of different components during composting and relationships between main composting factors and material consumption. The results indicated that the force aeration treatment without any exogenous inocula(T2) had the maximum reduction in the total fresh substance, followed by the force aeration treatment with one type of exogenous microbial inocula(T3), the treatment without any aeration or exogenous inocula(T1), and the force aeration treatment with two types of exogenous inocula(T4). For the force aeration treatments, the stage from 7 d to 13 d had the highest reduction of the fresh wastes throughout the composting. The decrease in the total weight of the fresh substances was attributed to the water loss in all treatments, but different treatments had different preferred ways of water removal. The addition of exogenous microbial inocula did reduce the leachates and increase the percentages of evaporated water. The consumption of the chemical elements of dry substances varied among different treatments. Both carbon loss/dry substance loss ratios and hydrogen loss/dry substance loss ratios were in order of T4>T3>T2>T1; the oxygen loss/dry substance loss ratios exhibited the opposite order among the treatments. In addition, the carbon consumption in all treatments mainly happened at the stage of 0~13 d, which accounted for more than 60% of the total carbon consumption. The RDA analysis indicated that temperature and bacteria had the most significant influences on the reduction behaviors of materials. The composting temperature associated highly with the reduction of the total fresh substance and water loss, while the population of bacteria, actinomycetes and fungi had the strongest relationship with the dry matter loss, the hydrogen element loss and the oxygen element loss, respectively. These results can provide some theoretical guidance for leachate discharge, element loss control and process improvement in the composting process.