The rate of nitrous oxide emission from a laboratory sequence batch reactor （SBR） wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of ...The rate of nitrous oxide emission from a laboratory sequence batch reactor （SBR） wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 h for aeration, 3.5 h for stirring without aeration, 0.5 h for settling and drainage, and 4 h of idle. The sludge was acclimated by running the system to achieve a stable running state as chemical oxygen demand, NO2^-, NO3^-, NH4^＋, pH, and N2O. indicated by rhythmic changes of total N, dissolved oxygen, Under the present experimental conditions measured nitrous oxide emitted from the off-gas in the aerobic and anaerobic phases, respectively, accounted for 8.6%-16.1% and 0-0.05% of N removed, indicating that the aerobic phase was the main source of N2O emission from the system. N2O dissolved in discharged water was considerable in term of concentration. Thus, measures to be developed for the purpose of reducing N2O emission from the system should be effective in the aeration phase.展开更多
Process control is an effective approach to reduce the NOx emission from sintering flue gas.The effects of different materials adhered on coke breeze on NOx emission characteristics and sintering performance were stud...Process control is an effective approach to reduce the NOx emission from sintering flue gas.The effects of different materials adhered on coke breeze on NOx emission characteristics and sintering performance were studied.Results showed that the coke breeze adhered with the mixture of CaO and Fe2O3 or calcium ferrite significantly lowers the NOx emission concentration and conversion ratio of fuel-N to NOx.Pretreating the coke with the mixture of lime slurry and iron ore fines helped to improve the granulation effect,and optimize the carbon distribution in granules.When the mass ratio of coke breeze,quick lime,water and iron ore fines was 2:1:1:1,the average NOx emission concentration was decreased from 220 mg/m3 to 166 mg/m3,and the conversion ratio of fuel-N was reduced from 54.2%to 40.9%.展开更多
A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good bio...A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.展开更多
Waste disposal is a major source of greenhouse gas emissions such as methane, carbon dioxide and nitrous oxide. In China, rapid economic growth and urbanization have led to increasing solid waste generation and greenh...Waste disposal is a major source of greenhouse gas emissions such as methane, carbon dioxide and nitrous oxide. In China, rapid economic growth and urbanization have led to increasing solid waste generation and greenhouse gas emissions from the waste sector. Based on the first-order decay （FOD） method recommended by the 2006 IPCC Guidelines, this paper systematically estimates China＇s carbon emissions from the waste sector and forecasts their peak. Results indicate that between 1981 and 2009, China＇s carbon emissions from the waste sector surged, possibly peaking by around 2024. In comparison with developed countries, there is a large potential to improve waste disposal in China. Industrial upgradation and waste disposal improvement will help reduce waste generation and carbon emissions from the waste sector.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 40471072 and 30470060) and the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-413-3-1).
文摘The rate of nitrous oxide emission from a laboratory sequence batch reactor （SBR） wastewater treatment system using synthetic wastewater was measured under controlled conditions. The SBR was operated in the mode of 4 h for aeration, 3.5 h for stirring without aeration, 0.5 h for settling and drainage, and 4 h of idle. The sludge was acclimated by running the system to achieve a stable running state as chemical oxygen demand, NO2^-, NO3^-, NH4^＋, pH, and N2O. indicated by rhythmic changes of total N, dissolved oxygen, Under the present experimental conditions measured nitrous oxide emitted from the off-gas in the aerobic and anaerobic phases, respectively, accounted for 8.6%-16.1% and 0-0.05% of N removed, indicating that the aerobic phase was the main source of N2O emission from the system. N2O dissolved in discharged water was considerable in term of concentration. Thus, measures to be developed for the purpose of reducing N2O emission from the system should be effective in the aeration phase.
基金Project(2017YFC0210302)supported by the National Key R&D Program of ChinaProjects(U1660206,U1760107)supported by the National Natural Science Foundation of China
文摘Process control is an effective approach to reduce the NOx emission from sintering flue gas.The effects of different materials adhered on coke breeze on NOx emission characteristics and sintering performance were studied.Results showed that the coke breeze adhered with the mixture of CaO and Fe2O3 or calcium ferrite significantly lowers the NOx emission concentration and conversion ratio of fuel-N to NOx.Pretreating the coke with the mixture of lime slurry and iron ore fines helped to improve the granulation effect,and optimize the carbon distribution in granules.When the mass ratio of coke breeze,quick lime,water and iron ore fines was 2:1:1:1,the average NOx emission concentration was decreased from 220 mg/m3 to 166 mg/m3,and the conversion ratio of fuel-N was reduced from 54.2%to 40.9%.
基金Shanghai Science and Technology Committee(No.042312045)Shanghai Post-doctor Fund
文摘A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.
文摘Waste disposal is a major source of greenhouse gas emissions such as methane, carbon dioxide and nitrous oxide. In China, rapid economic growth and urbanization have led to increasing solid waste generation and greenhouse gas emissions from the waste sector. Based on the first-order decay （FOD） method recommended by the 2006 IPCC Guidelines, this paper systematically estimates China＇s carbon emissions from the waste sector and forecasts their peak. Results indicate that between 1981 and 2009, China＇s carbon emissions from the waste sector surged, possibly peaking by around 2024. In comparison with developed countries, there is a large potential to improve waste disposal in China. Industrial upgradation and waste disposal improvement will help reduce waste generation and carbon emissions from the waste sector.
