The Process Optimization On Dry Anaerobic Digestion Technology Of Agricultural Waste And The Comprehensive Utilization Of Biogas Residue

Anaerobic digestion（AD）is a biological process that converts organic matter into a methane rich gas,the dry anaerobic digestion is characterized by total solids higher than 15%.In the recent years dry anaerobic digestion（DAD）has been attractive in comparison to wet AD（WAD）,dry AD has the advantages of smaller reactor space,less energy input and water consumption,and easy handling of the digestate,but sometimes the process shows inhibition problem,which may be due to requirement of large amount of inoculums,long retention time and the accumulation of VFAs.Based on the success and results made by the early researches in dry anaerobic digestion,this study took wheat straw,livestock manure and kitchen waste as raw material and doing research on processing optimized and the utilization of biogas residue.The main studies were as follows:（1）An experience was carried out using H₂SO₄,NaOH,urea,biogas slurry and microbial agent solutions different in concentration to pretreat wheat straw for dry anaerobic digestion to explore the relationships dosage with fiber structure of the pretreated wheat straw physico-chemical properties of the pretreatment solution.The results of SEM showed that pretreatment can destroy the stable structure of wheat straw in varying degrees,the NaOH solution produce great damage.The wheat straw after NaOH solution 2.0%and urea solution 0.5%showed the best biogas production abilities,the biogas yield reached 210.59 mL/g TS、195.73 mL/g TS,respectively,and the capacity aerogenesis rate reached 1.35 m3/m3·d、1.20 m3/m3·d,respectively.（2）This study took wheat straw,livestock manure and kitchen waste as raw materials and doing research on the influence of inoculation dose in the dry anaerobic digestion system with high propotion of straw.We carried out the experient of dry anaerobic co-digestion and take the inoculation concentration of 10%、20%、30%、40%、50%、60%.The results show that the system can start-up successfully except10%group was failed.The pH decreased at the beginning of anaerobic digestion,but the systems showed some self-regulation ability.After comprehensive comparis,it has been concluded that inoculation concentration of 40%is the best and the biogas yield reached 290.30 mL/g·VS,and the capacity aerogenesis rate reached 1.39 m3/m3·d.（3）The influence of Fe,Co,Ni in dry anaerobic co-digestion system in leachate recirculation conditions was be studied.The results show that adding Fe,Co,Ni at 1.0mg/L·d,0.1 mg/L·d,0.2 mg/L·d respectively can improve biogas production and system stability.The results Miseq sequencing analysis methanogenic bacteria community structure shows that supplementing trace elements improved the diversity and abundance of methanogenic bacteria,and also increased the proportion of Methanosarcina.（4）The climate in the north is cold in winter,and the green roofing plants are generally managed careless.Through designing several different formula substrates,cultivation experiment was carried out.The biomass and quality of Sedum lineare were determined.The results show that using a certain substrate formula can improve substrate permeability,water permeability,Sedum lineare can grow in good condition.After comprehensive comparis,the comprehensive quality of sedum lineare is the best when biogas:sandy loam soil=3:5.