CAJ | 학술논문

以水稻秸秆为原料，在恒温35℃和料液总固体质量分数为5%的条件下，以实验室内培养的不产气厌氧活性污泥为接种物，研究了稀碱水解、尿素氨化、生物酶解以及沼液预处理4种不同方式对秸秆厌氧发酵物能转化率、发酵周期、失重率以及木质纤维含量等方面的影响。结果表明，1.5% NaOH及6 d生物预处理可明显改善水稻秸秆干物质（total solid，TS）产气率，较空白分别提高44.0%和44.6%。0.4%低质量分数尿素预处理无法有效改善水稻秸秆的甲烷转化率，但通过调节C/N比可明显缩短发酵周期。与其他3种预处理相比，沼液预处理在提高秸秆物能转化率、缩短产气周期方面均有优势，其TS产气率达到333.9 mL/g，TS产甲烷率达到180.7 mL/g，分别较空白提高27.9%和21.2%。通过对厌氧发酵前后稻秆木质纤维含量比较分析，产气率与失重率有一定的关联，1.5%NaOH 处理样品发酵后纤维素、半纤维素损失最大，但沼液中高浓度的COD增加了后续处理的难度。因此秸秆沼气工程预处理方式的选择不仅需要考虑产气率的提升，也要顾及沼液后续处理等问题。沼液预处理可能成为今后水稻秸秆沼气工程较理想的方式。
이수도갈간위원료，재항온35℃화료액총고체질량분수위5%적조건하，이실험실내배양적불산기염양활성오니위접충물，연구료희감수해、뇨소안화、생물매해이급소액예처리4충불동방식대갈간염양발효물능전화솔、발효주기、실중솔이급목질섬유함량등방면적영향。결과표명，1.5% NaOH급6 d생물예처리가명현개선수도갈간간물질（total solid，TS）산기솔，교공백분별제고44.0%화44.6%。0.4%저질량분수뇨소예처리무법유효개선수도갈간적갑완전화솔，단통과조절C/N비가명현축단발효주기。여기타3충예처리상비，소액예처리재제고갈간물능전화솔、축단산기주기방면균유우세，기TS산기솔체도333.9 mL/g，TS산갑완솔체도180.7 mL/g，분별교공백제고27.9%화21.2%。통과대염양발효전후도간목질섬유함량비교분석，산기솔여실중솔유일정적관련，1.5%NaOH 처리양품발효후섬유소、반섬유소손실최대，단소액중고농도적COD증가료후속처리적난도。인차갈간소기공정예처리방식적선택불부수요고필산기솔적제승，야요고급소액후속처리등문제。소액예처리가능성위금후수도갈간소기공정교이상적방식。
China is a large agricultural country with the most abundant straw resources in the world, and about 700 million tons of crop straw is produced annually. However, most of the stalks are burned in harvest season, leading to severe air pollution and resource waste. Methane production through anaerobic digestion (AD) using agricultural straw is an important way to resolve the energy shortage in rural China. However, the AD technology is limited by low conversion efficiency due to the tight association among lignin, cellulose and hemicellulose. Therefore, pretreatments are necessary to facilitate biogas production by overcoming hydrolysis limitations. In the present study, we applied 4 pre-treatment methods i.e. sodium hydroxide (NaOH), urea, fungus and biogas slurry, to evaluate biogasification performance of rice straw via AD in laboratory scale. The pre-treatment temperature was 25℃, fermentation temperature was 35℃ and the total solids (TS) concentration was about 5%. Untreated rice straw substrate resulted into specific yields of methane and biogas of 149.1 and 261.1 L/kg, respectively. We found that AD with NaOH and biological treatment for rice straw increased biogas yield by 25%-44% and 19.4%-48.0%, respectively. Rice straw pretreated with urea of low concentration could not improve the methane yield (P=0.499), but could significantly shorten the fermentation period. Applying biogas slurry pre-treatment was found to be optimal, whose total biogas production was higher by 27.9%, whose methane yield was higher by 21.2%, and whose technical digestion time was shortened by 17.4%, compared to the untreated one. It was shown that weightlessness rate was proportional to the methane production, and methane production rate was negatively correlated to the content of cellulose and hemicelluloses after AD. Although 1.5% NaOH pretreatment could obtain the highest gas production rate, chemical oxygen demand (COD) of high concentration in biogas slurry after AD may increase the difficulty of subsequent treatment. The pretreatment costs were calculated to analyze which methods were fit for popularization. The variable costs included the fees for both raw materials and pretreatment reagents. We conclude that selecting the best pretreatment of straw in biogas project, not only needs to consider the gas production rate, subsequent processing, variable costs and other issues should also be taken into account. The pretreatment method with biogas slurry would be a more conducive and environmental friendly method.