The potential of periodate(PI)in sludge anaerobic digestion is not tapped,although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment.T...The potential of periodate(PI)in sludge anaerobic digestion is not tapped,although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment.This is the first work to demonstrate significant improvement in methane generation from waste activated sludge(WAS)with PI pretreatment and to provide underlying mechanisms.Biochemical methane potential tests indicated that methane yield enhanced from 100.2 to 146.3 L per kg VS(VS,volatile solids)with PI dosages from 0 to 100 mg per g TS(TS,total solids).Electron spin resonance showed PI could be activated without extra activator addition,which might be attributed to the native transition metals(e.g.,Fe2t)in WAS,thereby generating hydroxyl radical(-OH),superoxide radicals(-O2-),and singlet oxygen(1O2).Further scavenging tests demonstrated all of them synergistically promoted WAS disintegration,and their contributions were in the order of-O2->-OH>1O2,leading to the release of substantial biodegradable substances(i.e.,proteins and polysaccharides)into the liquid phase for subsequent biotransformation.Moreover,fluorescence and ultraviolet spectroscopy analyses indicated the recalcitrant organics(especially lignocellulose and humus)could be degraded by reducing their aromaticity under oxidative stress of PI,thus readily for methanogenesis.Microbial community analysis revealed some microorganisms participating in hydrolysis,acidogenesis,and acetoclastic methanogenesis were enriched after PI pretreatment.The improved key enzyme activities and up-regulated metabolic pathways further provided direct evidence for enhanced methane production.This research was expected to broaden the application scope of PI and provide more diverse pretreatment choices for energy recovery through anaerobic digestion.展开更多
Fact‑finding,as the foundation of a judicial decision,has been an important consideration in China’s judicial reform.This study introduces the theory of evidence‑based information and falsification methods in the fac...Fact‑finding,as the foundation of a judicial decision,has been an important consideration in China’s judicial reform.This study introduces the theory of evidence‑based information and falsification methods in the fact‑finding procedure of criminal investigations and proposes a paradigm for fact‑finding using combined pairs of approaches:individual evidence examination and global analysis,the objective basis and subjective perception of fact‑finders,and methods of verification and falsification.The working procedure of the paradigm is illustrated with the objective of making a contribution to the improvement of the existing model of fact‑finding in the criminal justice process.展开更多
基金funded by the National Key R&D Program of China(Grant No.2018YFE0106400).
文摘The potential of periodate(PI)in sludge anaerobic digestion is not tapped,although it has recently attracted great research interest in organic contaminants removal and pathogens inactivation in wastewater treatment.This is the first work to demonstrate significant improvement in methane generation from waste activated sludge(WAS)with PI pretreatment and to provide underlying mechanisms.Biochemical methane potential tests indicated that methane yield enhanced from 100.2 to 146.3 L per kg VS(VS,volatile solids)with PI dosages from 0 to 100 mg per g TS(TS,total solids).Electron spin resonance showed PI could be activated without extra activator addition,which might be attributed to the native transition metals(e.g.,Fe2t)in WAS,thereby generating hydroxyl radical(-OH),superoxide radicals(-O2-),and singlet oxygen(1O2).Further scavenging tests demonstrated all of them synergistically promoted WAS disintegration,and their contributions were in the order of-O2->-OH>1O2,leading to the release of substantial biodegradable substances(i.e.,proteins and polysaccharides)into the liquid phase for subsequent biotransformation.Moreover,fluorescence and ultraviolet spectroscopy analyses indicated the recalcitrant organics(especially lignocellulose and humus)could be degraded by reducing their aromaticity under oxidative stress of PI,thus readily for methanogenesis.Microbial community analysis revealed some microorganisms participating in hydrolysis,acidogenesis,and acetoclastic methanogenesis were enriched after PI pretreatment.The improved key enzyme activities and up-regulated metabolic pathways further provided direct evidence for enhanced methane production.This research was expected to broaden the application scope of PI and provide more diverse pretreatment choices for energy recovery through anaerobic digestion.
基金The work is supported by Social Science Foundation of Hebei Province under Grant No.HB18FX023,entitled as The Working Principle and Methods in Fact‑Finding of Criminal Cases.
文摘Fact‑finding,as the foundation of a judicial decision,has been an important consideration in China’s judicial reform.This study introduces the theory of evidence‑based information and falsification methods in the fact‑finding procedure of criminal investigations and proposes a paradigm for fact‑finding using combined pairs of approaches:individual evidence examination and global analysis,the objective basis and subjective perception of fact‑finders,and methods of verification and falsification.The working procedure of the paradigm is illustrated with the objective of making a contribution to the improvement of the existing model of fact‑finding in the criminal justice process.
