Efficiency And Functional Microbial Mechanism Of Aerobic Composting System On Cattle Manure/straw With Semipermeable Membrane

In recent years,with the rapid development of livestock and poultry breeding,the problems of livestock and poultry manure disposal become more and more significant.Untreated feces not only cause serious environmental damage,but also lead to waste of resources.By virtue of simple equipment,low investment,better product stability,etc,aerobic composting process has become one of the main ways to deal with livestock and poultry manure.However,the process is highly susceptible to external factors such as climate in the operation.The pile structure is vulnerable to damage at low temperatures in the rainy season and winter.Therefore,it has become an urgent problem how to develop an effective technology to ensure the stable operation of aerobic composting technology.In this paper,taking agricultural waste cow dung and straw as the research object,using semipermeable membrane aerobic composting process to explore its composting characteristics and effectiveness.According to the temperature change in the reactor,the composting process can be divided into three stages: 1-22 days for the heating stage;22-42 for the high temperature stage;42-60 days for the cooling and curing stage.The high temperature stage maintained for 8 days,GI Index was 83.53%.At the end of composting,the organic matter content was 27.05%,the C/N ratio was 22.8,p H 8.2,and the total nutrient was about 3%.Heavy metal content to meet the national agricultural industry standard "NY525-2012" on the organic fertilizer heavy metal content requirements,of which total arsenic 2.75mg/kg,total cadmium 1.5mg/kg,total chromium 86.1mg/kg,total mercury 0.05mg/kg,Total lead of 3.9mg/kg;high-throughput sequencing results show that the whole composting process,a total of 20 different classes of bacteria,mainly distributed Bacteroidia,Gammaprot eobacteria(γ-Proteus),Bacilli(Bacillus),Anaerolineae,Clostridia,Actinobacteria,Gemmatimonadetes,Alpha-proteobacteria,Flavobacteriia.Anaerobic composting and semipermeable membrane coverage were compared with aerobic composting efficiency,membrane-covered aerobic composting reached a temperature of 67 ℃ on day 2,while the anaerobic composting system reached a temperature of 60 ℃ on day 3.And the membrane is covered with aerobic compost and can be maintained at an optimum temperature of 55-65℃ over a long period of time.The effects of environmental factors on the degradation efficiency of straw were investigated by screening high temperature straw from the reactor at high temperature stage of aerobic composting.The removal rate of straw was 25.90%(C /N ratio 15,D)>22.83%(10% inoculation amount,A)>22.03%(20% inoculation amount,B)>11.60%(straw particle size 3cm,C)>11.26%(C/N ratio 60,E).The removal rate of ammonia and nitrogen was the best after 10 days of fermentation.B>C>D>A>E,and the removal rate of ammonia was the best.The release rate of polysaccharide was D > A > B > E > C;polysaccharide was highest when C/N ratio was 15;protein release was sorted by A>B>E>C>D,10% inoculation amount was the highest;humic acid concentration sorted B>C>D>E>A,inoculation amount of 20% of humic acid produced the most.