试验用作物秸秆与活性污泥混合厌氧发酵制备沼气,研究了活性污泥与麦秸、玉米秸和稻草高温干式发酵的产气规律,加N素调节碳氮比(C/N)及添加生物炭对产气的影响.利用作物秸秆与活性污泥投加量1∶1,厌氧发酵原料总固体(TS)20％,在55℃下厌氧发酵.试验数据表明:1)产气从第5d产气量开始增加,峰值均出现在第6～9 d,发酵15～25 d产气较为稳定,随后产气量缓慢下降.厌氧发酵7d时,沼气中甲烷含量均能达到60％左右.按厌氧发酵时长45 d计算,稻草的产气量最大,单位TS累积产气量达到413.7 mL·g-1;玉米秸和麦秸的单位TS累积产气量分别为365.2 mL·g-1、345.2 mL·g-1.2)调节发酵液的C/N至30∶1,可有效缩短沼气启动时间1～2 d;在沼气发酵微生物活性较低时,表现最为明显,可缩短沼气启动时间≥3 d且累积产气量最高可提高44.9％.3)在厌氧发酵液中添加4％(按发酵秸秆干基计算)的生物炭,并调节发酵液的C/N至30∶1,对麦秸厌氧发酵产气而言,累积产气量可提高38.5％,玉米秸和稻草的累积产气量分别提高6.2％和8.0％.%In this paper,the biogas was prepared by mixed anaerobic fermentation of crop straw and activated sludge.The high-temperature and dry anaerobic fermentation performance of mixed sludge with crop straw including wheat straw,corn stalk and rice straw and effects of carbon-nitrogen ratio and biochar additive on biogas production were studied.The anaerobic fermentation results showed as follows:1) Under the ratio of crop straw and activated sludge 1 ∶ 1,20％ of total solid and 55 ℃,the increasing of daily biogas production appeared on the fifth day with a peak value at the 6th-9th days.Then daily biogas production was stable during the 15th-25th days and decreased slowly later.The methane content of biogas reached about 60％ on the seventh day.In 45 days,the cumulative biogas production was the highest 413.7 mL· g-1 of rice straw,following 365.2 mL· g-1 of corn stalks and 345.2 mL· g-1 of wheat straw.2) Adjusted the carbon-nitrogen ratio of the fermentation reactants to 30 ∶ 1 could shorten the start-up time of biogas project by 1-2 d;when the biogas fermentation microbial activity is lower,the most obvious performance,can shorten the biogas start time ≥3 d and the cumulative gas production can be increased by 44.9％.3)4％ biochar additive (calculated according to the dry basis of the fermented straw) and C/N to 30∶1 could increase the cumulative biogas production by 38.5％ for wheat straw,following 6.2％ for corn stalks and 8.0％ for rice straw.
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