Effects of Adding Superphosphate and Sulfuric Acid on Carbon Greenhouse Gas Emissions and Carbon Conversion during Aerobic Composting Process

CHENG Zhiyuan; QIU Huizhen; SU Yangqin; PANG Yanan; LI Yun; ZHANG Chunhong; WANG Youling

doi:10.19672/j.cnki.1003-6504.0876.23.338

Abstract：To address the issues of the secondary pollution and compost product quality in the process of aerobic composting of farm wastes,a laboratory experiment of aerobic composting of cow dung and wheat straw was conducted by using a kind of closed forced ventilation system.The study of the experiment focused on the effects of adding additives such as superphos-phate(SP)and sulfuric acid(AS,20％V/V)into the process on the greenhouse gas emissions and carbon transformation during the composting.As a result,the experiment showed that sulfuric acid added affected the temperature-rise period in a certain degree,prolonging the time required for the pile to enter the high-temperature period;while adding both SP and AS could reduce greenhouse gas emission of composting,specially,AS contributed the effect more.Besides,the additives significantly reduced the carbon loss of aerobic composting;however,compared with SP,additive AS can significantly reduce the carbon loss in the form of gas;furthermore,the additives boosted the generation and accumulation of soluble carbon and humic acid.The result of the structural equation modelling indicated that there existed a certain conversion relationship between fulvic acid and humic acid,compared with the addition of AS,the addition of SP was more conducive to the conversion of fulvic acid to humic acid;and compared with the control group,the addition of SA remrkably promoted the degradation of lignin,cellulose and hemicellulose in the process of aerobic composting,but AS notably inhibited the degradation of lignocellulose.Finally,additives of and AS could promote the maturity of compost products,and especially adding SP could produce the best quality compost products.