Anaerobic Digestion Of Solid Waste Based On Composting Pretreatment And Utilizing Composting For Warming

With the improvement of peoples' life, the quantities of municipal solid waste (MSW) are rapidly increasing in China. Disposal of MSW had become a crucial problem which affected the living environment and hindered the development of society. MSW contained many reusable materials, so the aim of refuse treatment should turn to resource utilization in order to reduce social and environmental burden.The effects of the main factors on the anaerobic digestion of municipal solid waste based on composting pretreatment are studied. The results show that under the experimental condition, the eventual effect of composting pretreatment is conspicuous compared with non-composting pretreatment, and the best reaction parameter are: solid concentration of 10%, particle diameter of 5～10mm and agitation is adjusted properly according to the different periods of anaerobic digestion. Moreover, the correlation between biogas output and the changes of several hydrolases during the solid wastes fermentation is also studied in order to validate the feasibility and effectiveness of composting pretreatment. The results suggest that the enzyme activities of base protease, cellulose, amylase and amylase change during the biogas fermentation, which is associated with biogas output. The maximum value of hydrolase activity appears close to the peak biogas producing period while the activity of lipase keeps decreasing.Furthermore, based on the results of the reaction parameter optimum experiment, technical experiment of solid wastes is carried out. The study shows that anaerobic digestion of solid wastes by utilizing composting for warming is effective especially in winter and composting pretreatment of solid wastes has distinctively positive effect on the eventual treatment efficiency. However, it is also found that the result is not as well as that of the previous parameter optimum experiment. The main reason may be the large quantity of the treatment load, the weak function of hydraulic agitation and ammonia inhibition for anaerobic digestion.The thesis explores anaerobic digestion of municipal solid waste through best reaction indexes and microbial analysis. It can boast in its ability to offer foundation and reference for the design of anaerobic reactors, which provides an effective method for turning residues into biogas and recycling nutrients and ultimately realizes the goal of effective environmental management and synthetically utilizing benefit.