Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed...Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed associated with the hydrochar characteristics.The results suggested that Chlorella hydrochar(C-C)showed the highest cumulative yield of methane(approximately 345 mL)with high total organic carbon(TOC)removal efficiency and low volatile fatty acids(VAFs)concentration.Especially,food waste hydrochar(F-C)showed a poor effect on anaerobic digestion and aroused 1.4–1.6 g/L accumulation of VAFs,in which the toxic components may account for the low efficiency.The C-C and sludge hydrochar(S-C)may develop direct interspecific electron transport(DIET)to facilitate the generation of methane by both surface groups and conductivity of the body structure,unlike pinewood hydrochar(P-C),which mainly depended on the aromatic matrix structure of hydrochar body.This work suggested that C-C can be the best candidate for the facilitation of anaerobic digestion,and N-containing biowaste like algae and lignocellulose like pine wood may establish different DIET pathways based on the physicochemical characteristics of hydrochar.展开更多
Anaerobic digestion(AD)operating under conditions of organic overload stress typically exacerbates the potential for process instability,thereby resulting in significant economic and ecological ramifications.In this i...Anaerobic digestion(AD)operating under conditions of organic overload stress typically exacerbates the potential for process instability,thereby resulting in significant economic and ecological ramifications.In this investigation,an augmented substrate-to-inoculum ratio(S/I)along with varying total solid content(TS)levels was employed to replicate diverse organic loadings,utilizing maize straw and cattle manure.The findings reveal that a moderate augmentation in S/I and TS proves advantageous in augmenting methane yield,while an excessive substrate loading diminishes methane yield,hampers the kinetics of methane production,and even induces severe process instability.Kinetic study also displayed the variation of the model parameters for the first-order model,the modified Gompertze model,and the transfer function model.Both the modified Gompertze model and transfer function model exhibited the same environmental stress trend.Thus,both the increase in particulate content and the increase in S/I had a substantial effect on the substrate conversion rate to methane.Microbial analysis demonstrates the dominant influence of Firmicutes and Methanosarcina under different organic loading stresses.From both a kinetic and a microbiological point of view,this work provides novel insights into the fundamental processes that regulate anaerobic digestion(AD)under varying loading stress.Furthermore,it has significant implications for improving the operating efficiency of AD,which is a significant benefit.展开更多
The formation of humic-like acids(HLAs)is an essential process for converting liquid digestate into organic soil amendments to enhance agricultural sustainability.The aim of this study was to investigate the impact of...The formation of humic-like acids(HLAs)is an essential process for converting liquid digestate into organic soil amendments to enhance agricultural sustainability.The aim of this study was to investigate the impact of oxygen and/or MnO_(2)on the production of HLAs.Herein,abiotic humification performance of the digestate dissolved organic matter(DOM)is investigated with fluxes of air and N2 in the absence and presence of MnO_(2).Our results demonstrated that the fate of digestate DOM greatly depends on the oxidizing environment,the MnO_(2)enhanced nitrogen involved in the formation of HLAs.The synergistic effects of MnO_(2)and oxygen effectively improved the production of HLAs,and the corresponding component evolution was analyzed using spectroscopic evidence.The twodimensional correlation spectroscopy results demonstrated that the reaction sequence of digestate DOM followed the order of protein-like substances,substances with an absorbance at 325 nm,substances with UV absorbance at 254 nm and HLAs.Additionally,excitation emission matrix fluorescence combined with parallel factor analysis(EEM-PARAFAC)showed that tryptophan-like C3 was more prone to transformation than tyrosine-like C2 and was responsible for the humification process.The substance with an absorbance at 325 nm was a reaction intermediate in the transformation process of protein-like substances to HLAs.The above findings can be used to promote the production of liquid fertilizer associated with carbon sequestration as well as the sustainable development of biogas production.展开更多
Lignin degradation restricts corn stover anaerobic fermentation efficiency.The vacuum negative pressure aerobic hydrolysis pretreatment of corn stover was tested,and the optimal combined pretreatment conditions were p...Lignin degradation restricts corn stover anaerobic fermentation efficiency.The vacuum negative pressure aerobic hydrolysis pretreatment of corn stover was tested,and the optimal combined pretreatment conditions were presented in this paper.Because of the physical characteristics of light weight and large specific porosity of stover,it led to the formation of a scum layer during the fermentation process and thus reduced the gas production rate.In the pretreatment design,the vacuum conditions(0.02-0.08 MPa)and dwell time(5-20 min)were selected to see the changes of volumetric weight,swelling and specific porosity of corn stover,resulting in an increase of the volumetric weight by 7.18%-28.72%,an increase of the swelling by 3.18%-58.59%,and a decrease of the specific porosity by 9.34%-38.59%,as compared with the CK group.Continuous vacuum negative pressure treatment could discharge the air inside the stover destroy the microstructure,and cause the stover to settle more easily during the aerobic hydrolysis process.The optimal aerobic hydrolysis temperature and time were determined to be 39°C and 12.65 h,respectively.With the optimal pretreatment,the corn stover anaerobic fermentation test realized a cumulative methane yield of 260.44 mL/g VS,22.71%higher than CK group;meanwhile,the hydraulic retention time was shortened by 32.39%.展开更多
基金supported by the Opening Project of Key Laboratory of Agricultural Renewable Resource Utilization Technology (No.HLJHDNY2104)Funding for the National Natural Science Foundation of China (NSFC U21A20162)+2 种基金Heilongjiang Postdoctoral Financial Assistance (LBH-Z21042)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (UNPYSCT-2020106)Sichuan Science and Technology Program (2022NSFSC1162).
文摘Hydrochar prepared with four typical biowastes,pine wood,food waste,digested sewage sludge,and Chlorella were applied for the promotion of anaerobic digestion.The gas production and substrate composition were analyzed associated with the hydrochar characteristics.The results suggested that Chlorella hydrochar(C-C)showed the highest cumulative yield of methane(approximately 345 mL)with high total organic carbon(TOC)removal efficiency and low volatile fatty acids(VAFs)concentration.Especially,food waste hydrochar(F-C)showed a poor effect on anaerobic digestion and aroused 1.4–1.6 g/L accumulation of VAFs,in which the toxic components may account for the low efficiency.The C-C and sludge hydrochar(S-C)may develop direct interspecific electron transport(DIET)to facilitate the generation of methane by both surface groups and conductivity of the body structure,unlike pinewood hydrochar(P-C),which mainly depended on the aromatic matrix structure of hydrochar body.This work suggested that C-C can be the best candidate for the facilitation of anaerobic digestion,and N-containing biowaste like algae and lignocellulose like pine wood may establish different DIET pathways based on the physicochemical characteristics of hydrochar.
基金the Key R&D Project of Heilongjiang Province(Grant No.GY2021ZB0253/GA21D009)the Technological Project of Heilongjiang Province“the open competition mechanism to select the best candidates”(Grant No.2022ZXJ05C01)Guangzhou Science and Technology Plan Project(Grant No.2023B03J1229).
文摘Anaerobic digestion(AD)operating under conditions of organic overload stress typically exacerbates the potential for process instability,thereby resulting in significant economic and ecological ramifications.In this investigation,an augmented substrate-to-inoculum ratio(S/I)along with varying total solid content(TS)levels was employed to replicate diverse organic loadings,utilizing maize straw and cattle manure.The findings reveal that a moderate augmentation in S/I and TS proves advantageous in augmenting methane yield,while an excessive substrate loading diminishes methane yield,hampers the kinetics of methane production,and even induces severe process instability.Kinetic study also displayed the variation of the model parameters for the first-order model,the modified Gompertze model,and the transfer function model.Both the modified Gompertze model and transfer function model exhibited the same environmental stress trend.Thus,both the increase in particulate content and the increase in S/I had a substantial effect on the substrate conversion rate to methane.Microbial analysis demonstrates the dominant influence of Firmicutes and Methanosarcina under different organic loading stresses.From both a kinetic and a microbiological point of view,this work provides novel insights into the fundamental processes that regulate anaerobic digestion(AD)under varying loading stress.Furthermore,it has significant implications for improving the operating efficiency of AD,which is a significant benefit.
基金The authors are grateful for the financial support from the National Key Technology Research and Development Programs,China(No.2018YFC1901405)the National Natural Science Foundation of China(Grant No.52100167)+3 种基金the Natural Science Foundation of Hebei Province,China(No.B2020203024)the Key Research and Development Plan of Hebei Province,China(No.21327312D)the Young and Middle-Aged Science and Technology Innovation Leadership Talents Project of Xinjiang Production and Construction Corps,China(No.2019CB028)the Science and Technology Public Relations Projects in Key Fields of Xinjiang Production and Construction Corps,China(No.2019AB028).
文摘The formation of humic-like acids(HLAs)is an essential process for converting liquid digestate into organic soil amendments to enhance agricultural sustainability.The aim of this study was to investigate the impact of oxygen and/or MnO_(2)on the production of HLAs.Herein,abiotic humification performance of the digestate dissolved organic matter(DOM)is investigated with fluxes of air and N2 in the absence and presence of MnO_(2).Our results demonstrated that the fate of digestate DOM greatly depends on the oxidizing environment,the MnO_(2)enhanced nitrogen involved in the formation of HLAs.The synergistic effects of MnO_(2)and oxygen effectively improved the production of HLAs,and the corresponding component evolution was analyzed using spectroscopic evidence.The twodimensional correlation spectroscopy results demonstrated that the reaction sequence of digestate DOM followed the order of protein-like substances,substances with an absorbance at 325 nm,substances with UV absorbance at 254 nm and HLAs.Additionally,excitation emission matrix fluorescence combined with parallel factor analysis(EEM-PARAFAC)showed that tryptophan-like C3 was more prone to transformation than tyrosine-like C2 and was responsible for the humification process.The substance with an absorbance at 325 nm was a reaction intermediate in the transformation process of protein-like substances to HLAs.The above findings can be used to promote the production of liquid fertilizer associated with carbon sequestration as well as the sustainable development of biogas production.
基金supported by the Technological Project of Heilongjiang Province“the open competition mechanism to select the best candidates”(2022ZXJ05C01-03).
文摘Lignin degradation restricts corn stover anaerobic fermentation efficiency.The vacuum negative pressure aerobic hydrolysis pretreatment of corn stover was tested,and the optimal combined pretreatment conditions were presented in this paper.Because of the physical characteristics of light weight and large specific porosity of stover,it led to the formation of a scum layer during the fermentation process and thus reduced the gas production rate.In the pretreatment design,the vacuum conditions(0.02-0.08 MPa)and dwell time(5-20 min)were selected to see the changes of volumetric weight,swelling and specific porosity of corn stover,resulting in an increase of the volumetric weight by 7.18%-28.72%,an increase of the swelling by 3.18%-58.59%,and a decrease of the specific porosity by 9.34%-38.59%,as compared with the CK group.Continuous vacuum negative pressure treatment could discharge the air inside the stover destroy the microstructure,and cause the stover to settle more easily during the aerobic hydrolysis process.The optimal aerobic hydrolysis temperature and time were determined to be 39°C and 12.65 h,respectively.With the optimal pretreatment,the corn stover anaerobic fermentation test realized a cumulative methane yield of 260.44 mL/g VS,22.71%higher than CK group;meanwhile,the hydraulic retention time was shortened by 32.39%.
