文章实验采用产酸相中温产甲烷相高温两相发酵工艺,逐步提高系统中有机负荷,以此研究产甲烷相中氨氮浓度的变化规律及其影响。结果表明:氨氮浓度随有机负荷的提高而增大,当有机负荷提高到7.3 g VS·L-1d-1时,氨氮浓度上升到5386 mg&...文章实验采用产酸相中温产甲烷相高温两相发酵工艺,逐步提高系统中有机负荷,以此研究产甲烷相中氨氮浓度的变化规律及其影响。结果表明:氨氮浓度随有机负荷的提高而增大,当有机负荷提高到7.3 g VS·L-1d-1时,氨氮浓度上升到5386 mg·L-1,容积产气率最高达4.1 L·L-1d-1,系统运行良好;当有机负荷达到7.7 g VS·L-1d-1时,氨氮浓度达到6144 mg·L-1,系统出现氨氮抑制;抑制解除后,系统可在有机负荷为3.4 g VS·L-1d-1,氨氮浓度为4586 mg·L-1的条件下稳定运行,容积产气率达到2.5 L·L-1d-1。实验结果还显示:在高浓度氨氮条件下可强化乙酸的代谢,但对丙酸和丁酸的效果不明显。展开更多
2-Phase anaerobic digestion(AD), where the acidogenic phase was operated at 2 day hydraulic retention time(HRT) and the methanogenic phase at 10 days HRT, had been evaluated to determine if it could provide higher org...2-Phase anaerobic digestion(AD), where the acidogenic phase was operated at 2 day hydraulic retention time(HRT) and the methanogenic phase at 10 days HRT, had been evaluated to determine if it could provide higher organic reduction and methane production than the conventional single-stage AD(also operated at 12 days HRT). 454 pyrosequencing was performed to determine and compare the microbial communities. The acidogenic reactor of the 2-phase system yielded a unique bacterial community of the lowest richness and diversity, while bacterial profiles of the methanogenic reactor closely followed the single-stage reactor. All reactors were predominated by hydrogenotrophic methanogens, mainly Methanolinea. Unusually, the acidogenic reactor contributed up to 24%of total methane production in the 2-phase system. This could be explained by the presence of Methanosarcina and Methanobrevibacter, and their activities could also help regulate reactor alkalinity during high loading conditions through carbon dioxide production. The enrichment of hydrolytic and acidogenic Porphyromonadaceae, Prevotellaceae, Ruminococcaceae and unclassified Bacteroidetes in the acidogenic reactor would have contributed to the improved sludge volatile solids degradation, and ultimately the overall 2-phase system's performance. Syntrophic acetogenic microorganisms were absent in the acidogenic reactor but present in the downstream methanogenic reactor, indicating the retention of various metabolic pathways also found in a single-stage system. The determination of key microorganisms further expands our understanding of the complex biological functions in AD process.展开更多
The concept of temperature staged and biological phased(TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the efect of te...The concept of temperature staged and biological phased(TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the efect of temperature(35 to 70°C) as well as the hydraulic retention time(HRT)(2, 4 and 6 days) on the acidogenic phase. The results showed that the solubilization degree of wasteactivated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70°C, while the acidification degree was highest at 45°C(17.6%), and this was quite diferent from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days,4 days was chosen as the appropriate HRT because of its relatively high solubilization degree(24.6%) and acidification degree(20.1%)at 45°C. The TSBP system combined the acidogenic reactor(45°C, 4 days) with the methanogenic reactor(35°C, 16 days) and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35°C. Moreover, diferent microbial morphologies were observed in the acidogenicand methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that45°C was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufcient system.展开更多
文摘文章实验采用产酸相中温产甲烷相高温两相发酵工艺,逐步提高系统中有机负荷,以此研究产甲烷相中氨氮浓度的变化规律及其影响。结果表明:氨氮浓度随有机负荷的提高而增大,当有机负荷提高到7.3 g VS·L-1d-1时,氨氮浓度上升到5386 mg·L-1,容积产气率最高达4.1 L·L-1d-1,系统运行良好;当有机负荷达到7.7 g VS·L-1d-1时,氨氮浓度达到6144 mg·L-1,系统出现氨氮抑制;抑制解除后,系统可在有机负荷为3.4 g VS·L-1d-1,氨氮浓度为4586 mg·L-1的条件下稳定运行,容积产气率达到2.5 L·L-1d-1。实验结果还显示:在高浓度氨氮条件下可强化乙酸的代谢,但对丙酸和丁酸的效果不明显。
基金supported with funding from the National Research Foundation(NRF-CRP5-2009-02),Singapore for the project"Wastewater Treatment Plants as Urban Eco Power Stations"
文摘2-Phase anaerobic digestion(AD), where the acidogenic phase was operated at 2 day hydraulic retention time(HRT) and the methanogenic phase at 10 days HRT, had been evaluated to determine if it could provide higher organic reduction and methane production than the conventional single-stage AD(also operated at 12 days HRT). 454 pyrosequencing was performed to determine and compare the microbial communities. The acidogenic reactor of the 2-phase system yielded a unique bacterial community of the lowest richness and diversity, while bacterial profiles of the methanogenic reactor closely followed the single-stage reactor. All reactors were predominated by hydrogenotrophic methanogens, mainly Methanolinea. Unusually, the acidogenic reactor contributed up to 24%of total methane production in the 2-phase system. This could be explained by the presence of Methanosarcina and Methanobrevibacter, and their activities could also help regulate reactor alkalinity during high loading conditions through carbon dioxide production. The enrichment of hydrolytic and acidogenic Porphyromonadaceae, Prevotellaceae, Ruminococcaceae and unclassified Bacteroidetes in the acidogenic reactor would have contributed to the improved sludge volatile solids degradation, and ultimately the overall 2-phase system's performance. Syntrophic acetogenic microorganisms were absent in the acidogenic reactor but present in the downstream methanogenic reactor, indicating the retention of various metabolic pathways also found in a single-stage system. The determination of key microorganisms further expands our understanding of the complex biological functions in AD process.
基金supported by the National Hi-Tech Research and Development Program (863) of China (No.2009AA064702,2011AA060901)
文摘The concept of temperature staged and biological phased(TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the efect of temperature(35 to 70°C) as well as the hydraulic retention time(HRT)(2, 4 and 6 days) on the acidogenic phase. The results showed that the solubilization degree of wasteactivated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70°C, while the acidification degree was highest at 45°C(17.6%), and this was quite diferent from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days,4 days was chosen as the appropriate HRT because of its relatively high solubilization degree(24.6%) and acidification degree(20.1%)at 45°C. The TSBP system combined the acidogenic reactor(45°C, 4 days) with the methanogenic reactor(35°C, 16 days) and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35°C. Moreover, diferent microbial morphologies were observed in the acidogenicand methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that45°C was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufcient system.
