| Pretreatment to maize straw can play an important part in the anaerobic digestion process,which can improve the efficiency of biogas production, break the scum layer, and promote thedecomposition of straw. Maize straw was picked for the pretreatment material, and biologicalpretreatment agent was choosed for the pretreatment agent, which contained stem rot agent,“Result” microbe decomposition agent, compound microorganism bacterium agent, sugarfermentation enzyme, biogas slurry, cow dung filtrate and water. Maize straw was pretreatedunder different temperature. Through finding out the change rules form pH, total solid,volatile solid, carbon content, nitrogen congtent, biogas production rate, et al. This studyintended to explore the change of material characteristics and biogas production, to test theeffects of pretreatment conditions on anaerobic digestion, and select the best pretreatmentagents and pretreatment temperature.The main results obtained in this paper were listed as the followings:(1) After biological pretreatment, carbon nitrogen ratio was decreased. After pretreatedby biogas slurry, the C/N ratio of maize straw had felled by49.89%. Biogas slurry was thebest in pretreatment agent, which got the most gas production and its TS gas production was205.11ml/d. After pretreatment by “Result” microbe decomposition agent, maize straw waseasy generation acidification phenomenon during the digestion process, which leading torestrict the activity of methane bacteria. Asccharide fermented enzyme had the best effectduring the four mixed microorganism, however, stem rot agent had the worst effect.(2) In cow dung filtrate group, after different temperature pretreatment, maize straw haddifferent gas production, the total volume of biogas arranged from more to less order was:30℃>25℃>35℃>40℃> CK. In biogas slurry group, the total volume of biogasarranged from more to less order was:25℃>30℃> CK>40℃>35℃. In watertreatment group, the total volume of biogas arranged from more to less order was:30℃>CK>40℃>35℃>25℃.(3) Through three different pretreatment agent and different pretreatment temperature,maize straw got different gas effect, total gas production by arrange from more to less order was: biogas slurry25℃> biogas slurry30℃＞cow dung filtrate30℃> cow dung filtrate25℃> water treatment group30℃> biogas slurry control group> cow dung filtrate35℃>water control group> cow dung filtrate40℃=water treatment group40℃> biogas slurry40℃> water treatment group35℃> biogas slurry35℃> cow dung filtrate control group>water treatment group25℃.(4) pH value, the change of volatile fatty acid and total alkalinity had obvious influenceon the anaerobic fermentation. The ratio of total alkalinity and VFA determined the effect ofthe fermentation system. The higher the ratio, the higher the gas production rate offermentation system, whereas the gas effcienty of fermentation system is lower, even earlytermination of anaerobic fermentation. |
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