The effect of free ammonia on volatile fatty acid （VFA） accumulation and process instability was studied using a lab-scale anaerobic digester fed by two typical bio-wastes： fruit and vegetable waste （FVW） and foo...The effect of free ammonia on volatile fatty acid （VFA） accumulation and process instability was studied using a lab-scale anaerobic digester fed by two typical bio-wastes： fruit and vegetable waste （FVW） and food waste （FW） at 35℃ with an organic loading rate （OLR） of 3.0 kg VS/（m3-day）. The inhibitory effects of free ammonia on methanogenesis were observed due to the low C/N ratio of each substrate （15.6 and 17.2, respectively）. A high concentration of free ammonia inhibited methanogenesis resulting in the accumulation of VFAs and a low methane yield. In the inhibited state, acetate accumulated more quickly than propionate and was the main type of accumulated VFA. The co-accumulation of ammonia and VFAs led to an ＂inhibited steady state＂ and the ammonia was the main inhibitory substance that triggered the process perturbation. By statistical significance test and VFA fluctuation ratio analysis, the free ammonia inhibition threshold was identified as 45 mg/L. Moreover, propionate, iso-butyrate and valerate were determined to be the three most sensitive VFA parameters that were subject to ammonia inhibition.展开更多
Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor（IUSR） designed in this study was demon...Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor（IUSR） designed in this study was demonstrated in the treatment of concentrated black water and kitchen waste. The highest methane production of 48 L/person/day was achieved at the hydraulic retention time（HRT） of 7 days, while the other measures of performance at the HRT of 8.3 days were better than at the HRT of 7 or 10 days, achieving a methane production of 43 L/person/day, removal of total chemical oxygen demand（TCOD）of 89%, removal of soluble chemical oxygen demand（SCOD） of 92%, and conversion of chemical oxygen demand（COD） to methane of 71%. It is not recommended to decrease HRT lower than 7 days due to the instability of the initial period. The concentrations of volatile fatty acids（VFAs） in the IUSR were less than 10 mg/L, indicating that the anaerobic process was stable. Sludge bed development showed that sludge bed with high microbial activity was formed in the bottom and that the precipitation zone of effluents formed should preferably occupy 30% of the height of the IUSR. The effluents of the IUSR could be used for irrigation in agriculture in combination with a settling tank accompanied by disinfection to remove solids and pathogens.展开更多
为了解生物滤池/滴滤池在净化含NH;废气过程中N_(2)O排放情况并分析其影响因素。本研究依据Web of Science数据库检索发表于2006—2020年的国内外相关文献报道,并进行归纳总结和数据分析。结果表明:在生物滤池中,填料湿度、填料pH、NH;...为了解生物滤池/滴滤池在净化含NH;废气过程中N_(2)O排放情况并分析其影响因素。本研究依据Web of Science数据库检索发表于2006—2020年的国内外相关文献报道,并进行归纳总结和数据分析。结果表明:在生物滤池中,填料湿度、填料pH、NH;进气载荷等对N_(2)O排放有着重要影响;在滴滤池中,进气气体组分、NH;进气载荷和滴滤池构造等影响N_(2)O排放。总体而言,生物滤池/滴滤池相关的N_(2)O排放机理尚不清晰,仍需进一步研究。最后,结合生物滤池/滴滤池运行管理的研究成果,本研究就N_(2)O减排提出建议。展开更多
基金supported by the Ministry of Science and Technology of China(Nos.2008BADC4B18,2014BAC27B01)
文摘The effect of free ammonia on volatile fatty acid （VFA） accumulation and process instability was studied using a lab-scale anaerobic digester fed by two typical bio-wastes： fruit and vegetable waste （FVW） and food waste （FW） at 35℃ with an organic loading rate （OLR） of 3.0 kg VS/（m3-day）. The inhibitory effects of free ammonia on methanogenesis were observed due to the low C/N ratio of each substrate （15.6 and 17.2, respectively）. A high concentration of free ammonia inhibited methanogenesis resulting in the accumulation of VFAs and a low methane yield. In the inhibited state, acetate accumulated more quickly than propionate and was the main type of accumulated VFA. The co-accumulation of ammonia and VFAs led to an ＂inhibited steady state＂ and the ammonia was the main inhibitory substance that triggered the process perturbation. By statistical significance test and VFA fluctuation ratio analysis, the free ammonia inhibition threshold was identified as 45 mg/L. Moreover, propionate, iso-butyrate and valerate were determined to be the three most sensitive VFA parameters that were subject to ammonia inhibition.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2011ZX07301-003)the National Key Research and Development Plan (No. 2016YFC0400806)
文摘Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor（IUSR） designed in this study was demonstrated in the treatment of concentrated black water and kitchen waste. The highest methane production of 48 L/person/day was achieved at the hydraulic retention time（HRT） of 7 days, while the other measures of performance at the HRT of 8.3 days were better than at the HRT of 7 or 10 days, achieving a methane production of 43 L/person/day, removal of total chemical oxygen demand（TCOD）of 89%, removal of soluble chemical oxygen demand（SCOD） of 92%, and conversion of chemical oxygen demand（COD） to methane of 71%. It is not recommended to decrease HRT lower than 7 days due to the instability of the initial period. The concentrations of volatile fatty acids（VFAs） in the IUSR were less than 10 mg/L, indicating that the anaerobic process was stable. Sludge bed development showed that sludge bed with high microbial activity was formed in the bottom and that the precipitation zone of effluents formed should preferably occupy 30% of the height of the IUSR. The effluents of the IUSR could be used for irrigation in agriculture in combination with a settling tank accompanied by disinfection to remove solids and pathogens.
文摘为了解生物滤池/滴滤池在净化含NH;废气过程中N_(2)O排放情况并分析其影响因素。本研究依据Web of Science数据库检索发表于2006—2020年的国内外相关文献报道,并进行归纳总结和数据分析。结果表明:在生物滤池中,填料湿度、填料pH、NH;进气载荷等对N_(2)O排放有着重要影响;在滴滤池中,进气气体组分、NH;进气载荷和滴滤池构造等影响N_(2)O排放。总体而言,生物滤池/滴滤池相关的N_(2)O排放机理尚不清晰,仍需进一步研究。最后,结合生物滤池/滴滤池运行管理的研究成果,本研究就N_(2)O减排提出建议。
