Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different m...Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.展开更多
Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(...Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(30%, 60%, and 80%, dry matter) were applied to pretreat wheat straw for 7 days. The pretreated wheat straws were anaerobically digested at three loading rates(50, 65, and 80 g·L-1) to produce biogas. The results indicated that the wheat straw pretreated with 80% moisture content and 4% ammonia achieved the highest methane yield of 199.7 ml·g-1(based on per unit volatile solids loaded), with shorter digestion time(T80) of 25 days at the loading rate of 65 g·L-1compared to untreated one. The main chemical compositions of wheat straw were also analyzed. The cellulose and hemicellulose contents were decomposed by 2%-20% and 26%-42%, respectively,while the lignin content was hardly removed, cold-water and hot-water extracts were increased by 4%-44%, and12%-52%, respectively, for the ammonia-pretreated wheat straws at different moisture contents. The appropriate C/N ratio and decomposition of original chemical compositions into relatively readily biodegradable substances will improve the biodegradability and biogas yield.展开更多
文章基于不同含固率(TS)在粪秸厌氧共消化中产气率的不同,以碳素和氮素含量互补的全株甜高粱秸秆和奶牛粪为原料,评估在不同TS下厌氧共消化的产气特性。实验采用中温((37±0.5)℃)条件,底物中甜高粱与奶牛粪挥发性固体(VS)比为1∶1...文章基于不同含固率(TS)在粪秸厌氧共消化中产气率的不同,以碳素和氮素含量互补的全株甜高粱秸秆和奶牛粪为原料,评估在不同TS下厌氧共消化的产气特性。实验采用中温((37±0.5)℃)条件,底物中甜高粱与奶牛粪挥发性固体(VS)比为1∶1,设置奶牛粪的含固率为2%(T2组)、4%(T4组)、6%(T6组)、8%(T8组)4个处理组,分析不同TS组的产甲烷性能,动力学分析采用修正的Gompertz方程。结果表明,T2组的累积产气量为633.49 m L/(g VS)、累积甲烷产量为350.26 m L/(g VS),均为最高,随TS的增加累积产气率下降,高TS不利于沼气的生产。修正的Gompertz模型拟合结果R~2=0.988~0.999,随着TS的增加,延滞期变长,最大产甲烷速率降低,T2组与其他处理组相比混合消化体系最优。化学需氧量浓度和挥发性脂肪酸浓度均随着TS升高而升高。实验对全株甜高粱和奶牛粪的共消化高效产甲烷及过程稳定性控制具有指导意义。展开更多
The purpose of this study was to investigate the potential of high-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions, focusing on the effects of the strength and the amount of inoculum. ...The purpose of this study was to investigate the potential of high-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions, focusing on the effects of the strength and the amount of inoculum. Ensiled grass was inoculated with three different inocula; inoculum from liquid anaerobic digester（LI）, inoculum from dry anaerobic digester（DI）, and mixture of LI and DI（MI）, at feedstock-to-inoculum ratio（FIR） of 1, 2 and 4. The ensiling process of riverbank grass reduced moisture content（p 〉 0.05）, while the hemicellulose content was significantly increased from 30.88% to 35.15%（p 〈 0.05）, on dry matter basis. The highest methane production was at an FIR of 2 with MI（167 L/kg VSadded）,which was significantly higher（p 〈 0.05） than with DI, but not significant compared to LI（p 〉 0.05）. At an FIR of 4, digesters inoculated with LI and DI failed to produce methane,whereas 135 LCH4/kg VSaddedwas obtained with MI. The kinetic studies showed that at an FIR of 1 with LI and MI, the inoculum had less of effects on the hydrolysis rate constant（0.269 day-1and 0.245 day-1） and methane production（135 versus 149 L/kg VSadded）; rather,it affected the lag phase. In a thermophilic HS-AD of riverbank grass, the mixture of inoculum with low and high total solids content（TS） helps increase the TS of inoculum and digestion process. An FIR of 2 was deducted to be the limit for a better startup time and higher volumetric productivity of methane.展开更多
基金Supported by the Natural Science Foundation of Heilongjiang Province(QC2014C031)Returned Overseas Foundation of Heilongjiang Province(LC2013C07)+2 种基金Outstanding Academic Leaders Foundation of Harbin City(2013RFXYJ015)Young Reserve Talent Foundation of Harbin City(2014RFQYJ141)Outstanding Young Foundation of Heilongjiang Academy of Agricultural Sciences(2013JCQN003)
文摘Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.
基金Supported by the National High Technology Research and Development Program of China(2008AA062401)the China-US International Cooperation Project(2011DFA90800)the Ministry of Science and Technology,China
文摘Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(30%, 60%, and 80%, dry matter) were applied to pretreat wheat straw for 7 days. The pretreated wheat straws were anaerobically digested at three loading rates(50, 65, and 80 g·L-1) to produce biogas. The results indicated that the wheat straw pretreated with 80% moisture content and 4% ammonia achieved the highest methane yield of 199.7 ml·g-1(based on per unit volatile solids loaded), with shorter digestion time(T80) of 25 days at the loading rate of 65 g·L-1compared to untreated one. The main chemical compositions of wheat straw were also analyzed. The cellulose and hemicellulose contents were decomposed by 2%-20% and 26%-42%, respectively,while the lignin content was hardly removed, cold-water and hot-water extracts were increased by 4%-44%, and12%-52%, respectively, for the ammonia-pretreated wheat straws at different moisture contents. The appropriate C/N ratio and decomposition of original chemical compositions into relatively readily biodegradable substances will improve the biodegradability and biogas yield.
文摘文章基于不同含固率(TS)在粪秸厌氧共消化中产气率的不同,以碳素和氮素含量互补的全株甜高粱秸秆和奶牛粪为原料,评估在不同TS下厌氧共消化的产气特性。实验采用中温((37±0.5)℃)条件,底物中甜高粱与奶牛粪挥发性固体(VS)比为1∶1,设置奶牛粪的含固率为2%(T2组)、4%(T4组)、6%(T6组)、8%(T8组)4个处理组,分析不同TS组的产甲烷性能,动力学分析采用修正的Gompertz方程。结果表明,T2组的累积产气量为633.49 m L/(g VS)、累积甲烷产量为350.26 m L/(g VS),均为最高,随TS的增加累积产气率下降,高TS不利于沼气的生产。修正的Gompertz模型拟合结果R~2=0.988~0.999,随着TS的增加,延滞期变长,最大产甲烷速率降低,T2组与其他处理组相比混合消化体系最优。化学需氧量浓度和挥发性脂肪酸浓度均随着TS升高而升高。实验对全株甜高粱和奶牛粪的共消化高效产甲烷及过程稳定性控制具有指导意义。
文摘The purpose of this study was to investigate the potential of high-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions, focusing on the effects of the strength and the amount of inoculum. Ensiled grass was inoculated with three different inocula; inoculum from liquid anaerobic digester（LI）, inoculum from dry anaerobic digester（DI）, and mixture of LI and DI（MI）, at feedstock-to-inoculum ratio（FIR） of 1, 2 and 4. The ensiling process of riverbank grass reduced moisture content（p 〉 0.05）, while the hemicellulose content was significantly increased from 30.88% to 35.15%（p 〈 0.05）, on dry matter basis. The highest methane production was at an FIR of 2 with MI（167 L/kg VSadded）,which was significantly higher（p 〈 0.05） than with DI, but not significant compared to LI（p 〉 0.05）. At an FIR of 4, digesters inoculated with LI and DI failed to produce methane,whereas 135 LCH4/kg VSaddedwas obtained with MI. The kinetic studies showed that at an FIR of 1 with LI and MI, the inoculum had less of effects on the hydrolysis rate constant（0.269 day-1and 0.245 day-1） and methane production（135 versus 149 L/kg VSadded）; rather,it affected the lag phase. In a thermophilic HS-AD of riverbank grass, the mixture of inoculum with low and high total solids content（TS） helps increase the TS of inoculum and digestion process. An FIR of 2 was deducted to be the limit for a better startup time and higher volumetric productivity of methane.
