Study On Anaerobic Biodegradability And Degradation Mechanism Of Straw

In our country, A great various kinds of straws are produced every year.Contrary to traditional handling of biomass waste, anaerobic fermentationtechnology, which can produce the biomass energy and sources-straw biologicalgas by fermenting straws, have taken many attentions. However, because oflacking study of the enchasing structure of straw lignin and cellulose, strawdegrading performance and mechanism, the efficiency of anaerobic fermentationis low and the biomass conversion rate is not high. All of those become thetechnical bottleneck of developing the straw anaerobic fermentationindustrialization. Contraposing the bottleneck, we used the wheat straw as rawmaterial to expounded the structure of the wheat straw changes, anaerobicbiological degradation performance and the degradation mechanism and studiedthe process that based on the anaerobic fermentation via a new method ofanaerobic fermentation.In this paper, the main research contents three main parts. The technologicalconditions of anaerobic fermentation at moderated temperature were studied toensure the optimum starting conditions of the dry anaerobic fermentation. Thefibrous structure of straws before and after by pretreatment of ammoniation wereanalysed by FTIR、SEM、GBX and TAG.Particularlly, the processes of anaerobicpretreatment of ammoniation of wheat straw and anaerobic biologicaldegradation were researched.The factors, such as Straw composition,Fermentation gas production, COD concentration and pH of fermentation liquidwere analyzed.The results show that:(1)Under conditions addition amount of carbamide forraw material was4.5%, mass ration of manure to raw material was1:2and massratio of sludge inoculums accounted for fermentation material was45%， thebiogas had the highest output and the maximum of gas producing speed.(2)It alsoshows that the structure of the straws changed after the ammoniation pretreatment, part of functional groups were destroyed, the cellulose separatefrom the lignin. The waxiness layer of the straws was destroyed, and thedewatering surface of the straw became hydrophilic. The thermal stabilitycharacteristic of the straws was improved by the ammoniation pretreatment. Itmeans that the root causes of the improvement output of dry anaerobicfermentation are the change of the cellulose structure of the straw.(3)It wasobvious to see that the output of the methane after straws treated by anaerobicpretreatment of ammoniation was higher than that of straws treated by traditionalanaerobic fermentation. The sweat sustained for50days, and the volume ofcumulative gas was11263.27ml, enhance55.6%than that of untreated oneswhich was5011.32ml only. The cycle of gas production withamine-functionalized wheat straw shorten5days compared with39days in thatof untreated straws, and unit gas production increased15%.