Optimization Of Technical Parameters Of Municipal Sludge Aerobic Fermentation And Study On Plant Effect Of Its Fermentation Products

In recent years,with the development of urbanization and the continuous expansion of domestic sewage treatment facilities,secondary pollution caused by municipal sludge has become more and more serious.Sludge aerobic fermentation technology is considered to be a promising final disposal method of sludge,which can realize harmless,stable and resource recovery of sludge.But the traditional aerobic fermentation technology has some problems,such as low fermentation temperature,long cycle and poor fermentation products.In order to overcome the defects of traditional aerobic fermentation technology,this topic studied a sludge ultra-high temperature aerobic fermentation technology,municipal sludge as the substrate,rice straw as the conditioner,focusing on the environmental temperature,ventilation volume and the dosage of bacteria on the effects of aerobic fermentation,optimal control parameters;The dynamic changes of microbial community structure and the effects of fermentation products on plant growth during aerobic fermentation were studied.The main research contents and conclusions are as follows:(1)Single factor experiments were carried out by changing the specific parameters of ambient temperature,ventilation volume and inoculant dosage in aerobic fermentation system,and the physicochemical and biological indexes in the fermentation process were analyzed.The optimal operating parameters were determined as follows:ambient temperature 30℃,ventilation volume 5 L/min(2.12 m~3/(m~3·h))and inoculant dosage 0.5%.Under these conditions,it was found that during the fermentation process,the temperature of the reactor can be kept above 60℃for more than 5 days,the final moisture content can reach 39.24%,the coliform group value is 0.4,the GI value of the fermentation product can reach 134%,and the final ammonium nitrogen content is 401.18 mg/kg,which can make the sludge reduction,harmless and stable recycling.(2)On the basis of the optimal operating parameters,the experiment of sludge aerobic fermentation was carried out,and the high-throughput sequencing technology was used to detect the microbial communities at different stages of the fermentation process.The analysis showed that the microbial community structure was constantly evolving with the progress of aerobic fermentation.Firmicutes were the dominant bacteria in the high temperature stage,and Actinomyces,Bacteroidetes and Proteobacteria were the dominant bacteria in other fermentation stages.In the heating stage of aerobic fermentation,the microbial community richness and diversity were the highest.The similarity of microbial community composition was the highest between the warming stage and the cooling stage,and the difference between the initial stage and the high temperature stage was the greatest.(3)On the basis of the optimum operating parameters,the sludge aerobic fermentation experiment was carried out to obtain the final fermentation product.With garden soil as the reference group,the effects of three different types of sludge(fermentation product,dehydrated sludge and mixed sludge(fermentation initial material))on the growth of ryegrass were compared and analyzed.The results showed that dehydrated sludge and mixed sludge inhibited the growth of ryegrass.The effects of different sludge application ratios(5%,10%,20%,50%and 100%)on the growth of ryegrass were compared and analyzed.The results showed that appropriate amount of fermentation products could promote the growth of ryegrass,and the optimal application ratio was 5%.Figure[35]table[11]reference[145]...