Effect Of The Addition Of Sludge Mature Compost On Kitchen Waste Composting Process

Aerobic composting of kitchen waste is a promising technology,but there are still some problems such as slow degradation of organic matter.Sludge mature compost has the characteristics of large output and rich microbial species.It is important to investigate whether sludge mature compost can improve the composting process of kitchen waste and the mechanism of its action.The effect of ventilation on the composting process of kitchen waste,including the changes of physicochemical indicators and microbial community,was investigated by setting different ventilation conditions,using static composting and intermittent turning of the pile,and studying the effect of ventilation on the degradation of organic matter and humification process of kitchen waste.The experimental results showed that high ventilation increased the abundance of Basidiomycota,Thermobifida and Pseudoxanthomonas in the middle stage of composting,promoted cellulose degradation and humus precursors production,thus accelerating the aromatization process,but promoted the decomposition of huminic acid in the late stage of composting;low ventilation will delay the conversion of fulvic acid to humic acid.Adding ultra-high temperature sludge mature compost and high temperature sludge mature compost respectively to the kitchen waste pile,and setting the high and low addition ratios for static composting.By setting high and low ventilation conditions and analyzing various physicochemical in the composting process,including lignocellulose content and different molecular weight distribution of DOM,the effects of sludge mature compost on the degradation of organic matter and the humification process of food waste composting;the mechanism of the influence of humification was explored by means of infrared spectroscopy(FTIR)and high-throughput sequencing.The results showed that mature compost could prolong the duration of the compost temperature above 60℃ and increase the peak of the compost temperature,which led to the promotion of the degradation of VS and the conversion of fulvic acid to huminic acid in the composting process.The synthesis of huminic acid was postponed and the humus was dominated by fulvic acid with low ventilation levels during the high temperature period of composting.Meanwhile,the abundance of Basidiomycota was increased in the late stage of the composting,which enhanced the degradation of lignin and the decomposition of fulvic acid and the synthesis of humic acid.The abundance of Bacillus was also increased by promoting the degradation of nitrogenous organic matter and A has stronger facilitation than the other groups.Moreover,the abundance of nitrobacteria(Pseudomonas and Pusillimonas)was reduced,which inhibited nitrification and had a stronger inhibitory effect of B.The addition of mature compost A and B promoted the conversion of fulvic acid to huminic acid with low ventilation levels during the high temperature period and cool down period and huminic acid was main components of humus.Then the aromatization process was obviously improved and the former had a more pronounced effect.In addition,the strongest ammonification effect was observed with the addition of mature compost B.So the abundance of Bacillus was greater than the other groups.Also,mature compost A fostered re-decomposition of huminic acid in the late period of composting.Furthermore,the relative abundance of Basidiomycota,which could directly mineralize lignin,was enhanced at the high percentage of mature compost.And mineralisation of macromolecular organic matter such as lignocellulose was promoted,which resulted in reducing the production of humus precursors and the inhibition of their synthesis,with a larger proportion of small molecules in DOM(62%)than in the control(34%).The relative abundance of Pusillimonas,Pseudomonas,Nitrosomonas and other nitrobacteria was increased,which enhanced nitrification.