Effect Of Silicon Pumice On Greenhouse Gases Emissions And Humus In The Aerobic Composting Process Of Pig Manure

With the rapid development of large-scale livestock and poultry breeding industry,the output of livestock and poultry manure increases sharply,which causes severe contamination and even endangers human health.Resource utilization is the core content of livestock and poultry manure pollution prevention and control.Aerobic composting can effectively transform livestock and poultry manure into mature and stable compost products,and is the most commonly used technology for livestock and poultry manure resource utilization.However,the traditional aerobic compost has the problems of large greenhouse gas emission,serious nitrogen loss and low humification degree,which can reduce the quality of compost products and easily cause secondary pollution to the environment.The improvement of composting conditions has been a hot topic,and the additive can optimize the compost condition by adjusting the physical and chemical parameters.The excellent performance of silicon pumice can regulate the physical and chemical parameters of the reactor to a certain extent,silicon pumice is a new porous compound made from waste glass and shell powder.It has stable chemical properties,strong adsorption ability and no toxicity and no pollution.It has good effect on soil improvement and water quality purification.In order to investigate the effect of silicon pumice as additive on compost,the aerobic composting experiment was carried out for 42 days with pig manure as compost raw material,wheat straw as conditioning agent and silicon pumice as additive,to explore the effects of different proportions（0%,2.5%,5%and 10%）of silicon pumice on greenhouse gas emissions,nitrogen retention,humification degree and final product quality and agricultural value during pig manure aerobic composting.This study can evaluate the effect of silicon pumice on pig manure aerobic composting and its application potential in practical engineering.The main results and conclusions are listed as below:（1）After 42 days aerobic composting experiment,all treatments reached the hygienic standard and met the requirements of composting maturity.At the end of composting,the organic matter contents of 0%,2.5%,5%and 10%silicon pumice treatments were 65.35%,63.55%,60.75%and 57.15%,respectively.Silicon pumice as an additive can prolong the high temperature duration of compost and increase the degradation rate of organic matter.（2）The addition of silicon pumice has obvious effect on greenhouse gas emission reduction and nitrogen retention in composting process.the CH₄,N₂O and NH₃emissions with silicon pumice treatment decreased by 18.27%-30.41%,26.89%-84.16%and 10.41%-23.70%compared with the control,respectively.Besides,the equivalent value of greenhouse gas carbon dioxide was reduced by 9.94%-26.44%in the composting of silicon pumice,meanwhile,the total kjeldahl nitrogen content was higher than control treatment.,which could effectively control the greenhouse effect and the effect of adding 10%silicon pumice was the most significant.（3）Adding silicon pumice to compost can improve the degradation of volatile fatty acids（VFAs）in compost.Compared with the control,the amount of odor unit added to the treatment of silicon pumice decreased,and the silicon pumice could reduce the odor produced in the composting process and accelerate the composting process,of which 10%of the treatment effect was the most obvious.（4）The addition of silicon pumice in compost promotes the degradation of organic matter and the formation of humus.The analysis of uv-vis,synchronous fluorescence,emission fluorescence and fourier infrared spectra also further confirmed that the addition of silicon pumice can effectively increase the aromatization degree of the bulk material,and the optimum addition dose is 10%,respectively.（5）Compared with the control,the content of humic acid increased by 4.53%-18.27%in silicon pumice treatment.,the degree of polymerization and seed germination index improved,enhanced rot proficiency.In conclusion,silicon pumice can effectively reduce greenhouse gas emission,reduce nitrogen loss,accelerate the degradation of VFAs,promote the degradation and humification of organic matter,and ultimately improve the quality and agricultural value of the composting products.Silicon pumice has a broad application prospect in the actual composting engineering.