Study On Composting Characteristics Of Multi-Source Mixed Materials By High Temperature Pretreatment

Aerobic composting is an effective method to treat agricultural solid organic waste.However,the use of traditional composting methods to treat agricultural solid organic waste has long fermentation cycles,low composting efficiency,serious nitrogen loss,and greenhouse gas and ammonia emissions.Cause environmental pollution and other problems.High-temperature pretreatment composting can effectively solve these problems.For this reason,this research uses the high-temperature pretreatment composting process to treat the mixed solid organic wastes of multiple materials in rural areas.Through the use of different pretreatment temperatures and pretreatment times during the fermentation process,and analysis of the physical and chemical properties and the law of nitrogen conversion during the fermentation process,On this basis,the physical and chemical properties of the high-temperature pretreatment compost of the multi-element mixture,the conversion law of carbon-containing greenhouse gas and the emission law of ammonia gas are studied to obtain the best pretreatment temperature and the best pretreatment time of the high-temperature pretreatment compost,which is high temperature The practical application of pretreatment composting in the treatment of multi-component mixtures provides scientific basis and technical support.The main conclusions are as follows:（1）Study the effects of different high temperature pretreatment temperatures on composting.Through analyzing the temperature,moisture content,pH and other physical and chemical properties and relevant parameters of nitrogen during the composting process at 70℃,80℃and CK,it is found that 70℃and 80℃treatments It can quickly enter the high temperature stage（above 60℃in the second day）,and can significantly increase the decomposing of the pile and the degradation rate of organic matter.At the end of composting,the TN content of 70℃and 80℃treatment increased by 2.93%and 2.78%compared with the initial,and the seed germination rate reached91.2%and 89.9%.It can be found through SEM path analysis that after 70℃and 80℃high temperature pretreatment,NH₄⁺-N can be converted into acid-hydrolyzed ammonium nitrogen（AN）,which is easy to use by plants,indicating that the high-temperature pretreatment composting process can significantly increase the temperature of the compost,shorten the composting cycle,reduce the loss of nitrogen in the compost,and improve the quality of the compost product.The treatment at 70℃and80℃has little difference in the physical and chemical properties of composting and the conversion of nitrogen.In view of energy saving and economy,70℃is selected as the high temperature pretreatment temperature.（2）On the basis of the above experiments,the effects of different high-temperature compost pretreatment times on composting were studied.The results showed that different pretreatment times（1h,2h,and 3h）have an effect on the temperature and moisture content of each group of treated piles during the composting process.There is no significant difference in the effects of physical and chemical properties such as rate,pH,EC,TN,GI,etc.From the perspective of energy saving and economy,the best high-temperature compost pretreatment time should be 1h.（3）Study the compost ratio of the multi-element mixture,analyze the temperature,moisture content,pH,EC and VS and other physical and chemical indicators,and find that when the ratio of tail vegetable to chicken manure to straw is 1:2 by mass,it is beneficial to increase the temperature of the pile.,Promote the maturity of compost.（4）Research the high-temperature pretreatment compost of multiple mixture materials,and analyze the temperature,moisture content,CH₄,CO₂and NH₃in the composting process of GL,YL and QL three groups,and find that different types of tail vegetables and chicken manure-straw mixed with high-temperature pretreatment and composting,there is no significant difference in the physical and chemical indicators.In the process of high-temperature pretreatment and composting,the temperature of the pile and the EC have a very significant positive correlation with CH₄,CO₂and NH₃,and the NO₃^--N has a significant negative correlation with CH₄,CO₂and NH₃.There is a negative correlation between NO₃^--N and NH₃.pH is significantly negatively correlated with CH₄and NH₃,but not significantly correlated with CO₂.NH₄⁺-N has a significant positive correlation with NH3,but has no significant correlation with CH₄and CO₂.The water content and VS have no obvious correlation with the three gases.