The International Commission on Stratigraphy and the IUGS Executive Committee have recently ratified a Global Standard Stratotype-section and Point(GSSP)defining the conterminous base of the third series and the fifth...The International Commission on Stratigraphy and the IUGS Executive Committee have recently ratified a Global Standard Stratotype-section and Point(GSSP)defining the conterminous base of the third series and the fifth stage of the Cambrian System.The series and the stage are respectively named the Miaolingian Series and Wuliuan Stage,after the Maioling Mountains in southeastern Guizhou and the Wuliu sidehill,Jianhe County,in eastern Guizhou Province,South China,where the GSSP is located.The GSSP is exposed in a natural outcrop near the Balang Village at a position of 26o44.843'N latitude and 108o24.830'E longitude.It is defined at the base of a silty mudstone layer 52.8 m above the base of the Kaili Formation in the Wuliu-Zengjiayan section,coinciding with the first appearance of the cosmopolitan oryctocephalid trilobite Oryctocephalus indicus(base of the O.indicus Zone).Secondary global markers at or near the base of the series and stage include the peak of a rather large negative carbon isotopic excursion(ROECE excursion),the simultaneous appearance of many acanthomorphic acritarch forms,a transgressive phase of a major eustatic event,and the last appearance of intercontinental polymerid trilobites,either Bathynotus or Ovatoryctocara.Faunal turnovers close to the base of the Miaolingian Series and Wuliuan Stage have been recognized as being at the base of the Oryctocephalus indicus Zone of Amgan Stage in Siberia,the Delamaran Stage in Laurentia,the Oryctocephalus indicus Zone in the Indian Himalaya and North Greenland,near the base of the Delamaran Stage in Australia,and within the Eccaparadocides sdzuyi Zone in Iberia and the Ornamentaspis frequens Zone in Morocco.展开更多
Thermal pretreatment can be applied to sludge anaerobic digestion or dewatering. To analyze the variation in humic substances during thermal sludge treatment, sludge humic and fulvic acids were extracted before and af...Thermal pretreatment can be applied to sludge anaerobic digestion or dewatering. To analyze the variation in humic substances during thermal sludge treatment, sludge humic and fulvic acids were extracted before and after 30-min thermal treatment at 180℃, and then their contents, molecular weight distributions, elementary compositions, and spectral characteristics were compared. The results showed that the total contents of humic and fulvic acids in the sludge almost remained constant during thermal treatment, but 35% ofhumic and fulvic acids were dissolved from the sludge solids. Moreover, both humic and fulvic acids were partly decomposed and 32% of humic acids were converted to fulvic acids. The median value of the molecular weights of humic acids decreased from 81 to 41 kDa and that of fulvic acids decreased from 15 to 2 kDa. Besides the reduction in molecular size, the chemical structures of humic and fulvic acids also exhibited a slight change, i.e. some oxygen functional groups disappeared and aromatic structures increased after thermal sludge treatment.展开更多
Microbial Fe(Ⅲ)reduction is a significant driving force for the biogeochemical cycles of C,O,P,S,N,and dominates the natural bio-purification of contaminants in groundwater(e.g.,petroleum hydrocarbons,chlorinated eth...Microbial Fe(Ⅲ)reduction is a significant driving force for the biogeochemical cycles of C,O,P,S,N,and dominates the natural bio-purification of contaminants in groundwater(e.g.,petroleum hydrocarbons,chlorinated ethane,and chromium).In this review,the mechanisms and environmental significance of Fe(Ⅲ)(hydro)oxides bioreduction are summarized.Compared with crystalline Fe(Ⅲ)(hydro)oxides,amorphous Fe(m)(hydro)oxides are more bioavailable.Ligand and electron shuttle both play an important role in microbial Fe(Ⅲ)reduction.The restrictive factors of Fe(Ⅲ)(hydro)oxides bioreduction should be further investigated to reveal the characteristics and mechanisms of the process.It will improve the bioavailability of crystalline Fe(Ⅲ)(hydro)oxides and accelerate the anaerobic oxidation efficiency of the reduction state pollutants.Furthermore,the approach to extract,culture,and incubate the functional Fe(Ⅲ)reducing bacteria from actual complicated environment,and applying it to the bioremediation of organic,ammonia,and heavy metals contaminated groundwater will become a research topic in the future.There are a broad application prospects of Fe(Ⅲ)(hydro)oxides bioreduction to groundwater bioremediation,which includes the in situ injection and permeable reactive barriers and the innovative Kariz wells system.The study provides an important reference for the treatment of reduced pollutants in contaminated groundwater.展开更多
The biologic treatment of the dewatering effluent from thermally treated sludge is difficult due to the high concentration of refractory humic substances. On the other hand, humic substances are an important source of...The biologic treatment of the dewatering effluent from thermally treated sludge is difficult due to the high concentration of refractory humic substances. On the other hand, humic substances are an important source of organic fertilizer. In this study, a novel process using ferric coagulant was developed to recover humic substances from dewatering effluent for use as an organic fertilizer. When ferric coagulant was applied to raw dewatering effluent, up to 70% of humic substances were enmeshed by hydrolyzed ferric ions at an optimum pH of 4.5. The proper mass ratio of iron ions to humic substances was 0.6. In the recovered material, humic substances accounted for 24.2% of the total dry solids, and the amount of phosphorus （equivalent phosphorus pentoxide） was 6.2%. Heavy metals and other components all met the legal requirements for organic fertilizer. When the recovered material was applied to soybeans, the germination and growth of the seeds was significantly improved.展开更多
基金supported in part by grants from the National Natural Science Foundation of China(49060010,40372023,41330101)the Ministry of Science and Technology of China(2006CB806401,2013CB835002,2015FY310100,12002CC2600)+3 种基金the National Commission on Stratigraphy of China(95-Special Project-01-1-6,DD20160120-04)the State Key Laboratory on Palaeobiology and Stratigraphy(20191101)the Guizhou Bureau of Science and Technology(CGSCFG-2010-7001Gui.Sci.Tal.[2017]5788)。
文摘The International Commission on Stratigraphy and the IUGS Executive Committee have recently ratified a Global Standard Stratotype-section and Point(GSSP)defining the conterminous base of the third series and the fifth stage of the Cambrian System.The series and the stage are respectively named the Miaolingian Series and Wuliuan Stage,after the Maioling Mountains in southeastern Guizhou and the Wuliu sidehill,Jianhe County,in eastern Guizhou Province,South China,where the GSSP is located.The GSSP is exposed in a natural outcrop near the Balang Village at a position of 26o44.843'N latitude and 108o24.830'E longitude.It is defined at the base of a silty mudstone layer 52.8 m above the base of the Kaili Formation in the Wuliu-Zengjiayan section,coinciding with the first appearance of the cosmopolitan oryctocephalid trilobite Oryctocephalus indicus(base of the O.indicus Zone).Secondary global markers at or near the base of the series and stage include the peak of a rather large negative carbon isotopic excursion(ROECE excursion),the simultaneous appearance of many acanthomorphic acritarch forms,a transgressive phase of a major eustatic event,and the last appearance of intercontinental polymerid trilobites,either Bathynotus or Ovatoryctocara.Faunal turnovers close to the base of the Miaolingian Series and Wuliuan Stage have been recognized as being at the base of the Oryctocephalus indicus Zone of Amgan Stage in Siberia,the Delamaran Stage in Laurentia,the Oryctocephalus indicus Zone in the Indian Himalaya and North Greenland,near the base of the Delamaran Stage in Australia,and within the Eccaparadocides sdzuyi Zone in Iberia and the Ornamentaspis frequens Zone in Morocco.
基金Acknowledgements This project was financially supported by the China Major Science and Technology Program for Water Pollution Control and Treatment （No. 2011ZX07302）, the Natural Science Foundation of China （Grant No. 51008174）, and the Joint Research Center of Urban Resource Recycling Technology of Graduate School at Shenzhen, Tsinghua University and Shenzhen Green Eco-Manufaeturer High-Tech Co. Ltd. （Grant No. URRT2013005）.
文摘Thermal pretreatment can be applied to sludge anaerobic digestion or dewatering. To analyze the variation in humic substances during thermal sludge treatment, sludge humic and fulvic acids were extracted before and after 30-min thermal treatment at 180℃, and then their contents, molecular weight distributions, elementary compositions, and spectral characteristics were compared. The results showed that the total contents of humic and fulvic acids in the sludge almost remained constant during thermal treatment, but 35% ofhumic and fulvic acids were dissolved from the sludge solids. Moreover, both humic and fulvic acids were partly decomposed and 32% of humic acids were converted to fulvic acids. The median value of the molecular weights of humic acids decreased from 81 to 41 kDa and that of fulvic acids decreased from 15 to 2 kDa. Besides the reduction in molecular size, the chemical structures of humic and fulvic acids also exhibited a slight change, i.e. some oxygen functional groups disappeared and aromatic structures increased after thermal sludge treatment.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21606214)the Water Pollution Control and Control of Major National Science and Technology Projects in China(No.2018ZX07109-003)。
文摘Microbial Fe(Ⅲ)reduction is a significant driving force for the biogeochemical cycles of C,O,P,S,N,and dominates the natural bio-purification of contaminants in groundwater(e.g.,petroleum hydrocarbons,chlorinated ethane,and chromium).In this review,the mechanisms and environmental significance of Fe(Ⅲ)(hydro)oxides bioreduction are summarized.Compared with crystalline Fe(Ⅲ)(hydro)oxides,amorphous Fe(m)(hydro)oxides are more bioavailable.Ligand and electron shuttle both play an important role in microbial Fe(Ⅲ)reduction.The restrictive factors of Fe(Ⅲ)(hydro)oxides bioreduction should be further investigated to reveal the characteristics and mechanisms of the process.It will improve the bioavailability of crystalline Fe(Ⅲ)(hydro)oxides and accelerate the anaerobic oxidation efficiency of the reduction state pollutants.Furthermore,the approach to extract,culture,and incubate the functional Fe(Ⅲ)reducing bacteria from actual complicated environment,and applying it to the bioremediation of organic,ammonia,and heavy metals contaminated groundwater will become a research topic in the future.There are a broad application prospects of Fe(Ⅲ)(hydro)oxides bioreduction to groundwater bioremediation,which includes the in situ injection and permeable reactive barriers and the innovative Kariz wells system.The study provides an important reference for the treatment of reduced pollutants in contaminated groundwater.
基金Financial support for this project was obtained from the China Major Science and Technology Program for Water Pollution Control and Treatment （No. 2011ZX07302）, the Natural Science Foundation of China （Grant No. 51478239）, and Shenzhen Science and Technology Research and Development Fund （No. JCYJ20150320154458994）.
文摘The biologic treatment of the dewatering effluent from thermally treated sludge is difficult due to the high concentration of refractory humic substances. On the other hand, humic substances are an important source of organic fertilizer. In this study, a novel process using ferric coagulant was developed to recover humic substances from dewatering effluent for use as an organic fertilizer. When ferric coagulant was applied to raw dewatering effluent, up to 70% of humic substances were enmeshed by hydrolyzed ferric ions at an optimum pH of 4.5. The proper mass ratio of iron ions to humic substances was 0.6. In the recovered material, humic substances accounted for 24.2% of the total dry solids, and the amount of phosphorus （equivalent phosphorus pentoxide） was 6.2%. Heavy metals and other components all met the legal requirements for organic fertilizer. When the recovered material was applied to soybeans, the germination and growth of the seeds was significantly improved.
