物料预处理对堆肥减量化、腐殖化和稳定化的影响及其微生物机制

Effect of windrow pretreatment on reduction and humification during composting and its microbial mechanism

堆肥是有机固体废弃物处理与资源化的主要途径之一,包括矿化和腐殖化两个过程,且都和微生物活动有关。矿化过程会产生二氧化碳(CO2)等温室气体,是一个典型的温室气体释放过程。腐殖化过程则会产生稳定的腐殖质,则是优良的土壤改良剂。在堆肥稳定化的前提下,如何有效减少堆肥过程中的CO2释放,强化堆肥的腐殖化过程,增加作为优良土壤改良剂的腐殖质产量,对于发展低碳化堆肥技术,实现堆肥的资源化利用具有重要意义。本文选取水稻秸秆和餐厨垃圾作为堆肥原料,研究不同预处理对堆肥过程中矿化和腐殖化过程的影响,并探讨了不同预处理影响矿化和腐殖化过程的微生物机理。结果表明堆料加热预处理后,堆肥的矿化作用被明显削弱,总碳(TC)减量率仅为23.4%,并且最后形成了可观产量的稳定腐殖质(每kg堆料70 d后腐殖质含量为22.09 g±0.35 g,腐殖化系数达2.0),因此加热预处理后的堆肥过程在保证稳定腐殖质的产量前提下更低碳化。预处理通过影响堆料的性质和初始状态下堆料中微生物的种类和数量从而影响堆肥的矿化和腐殖化过程。活性微生物量与脱氢酶活性是矿化过程的主要决定因素,而多酚氧化酶活性主要影响堆肥的稳定腐殖化过程。

Composting is one of the main ways of organic solid waste treatment and recycling, including two processes of mineralization and humification, both of which are related to microbial activity. The mineralization process as a typical greenhouse gas release process produces carbon dioxide （CO2 ） and other greenhouse gases. While the humification process will produce stable humus, which is good soil improver. How to reduce CO2 releasing during composting process and strengthen the humification is important for low-carbon composting of organic solid waste and for improving the quality of soil conditioner. In this research, agroforestry waste and restaurant garbage were chosen as raw material of compost to discuss effects of different pretreatment on quantitative reduction, humification, stabilization and as well as its mechanism. Results showed that through stacking heating pretreatment, mineralization of compost was reduced with only 23.4% reduction rate of total carbon （TC）, and finally formed stable humus considerable yield （per kg stacking humus content after 70 days was 22.09 g ± 0.35 g, humification coefficient of 2.0）. It indicated that composting process with heating pretreatment was lower carbonation under the guarantee of premise of stable humus yield. Pretreatment influenced the properties of windrow material stacking and initial state through types and quantity of microorganism, thus affecting the mineralization and humification process of composting. Microbial biomass and dehydrogenase activity were mainly decisive factors of the mineralization process, while polyphenol oxidase activity mainly affected the composting humification process stability.