Removal of inorganic nitrogen （inorganic-N） from toilet wastewater, using a pilot-scale airlift external circulation membrane bioreactor （AEC-MBR） was studied. The results showed that the use of AEC-MBR with limit...Removal of inorganic nitrogen （inorganic-N） from toilet wastewater, using a pilot-scale airlift external circulation membrane bioreactor （AEC-MBR） was studied. The results showed that the use of AEC-MBR with limited addition of alkaline reagents and volumetric loading rates of inorganic-N of 0.19-0.40 kg inorganic-N/（m^3·d） helped achieve the desired nitrification and denitrification. Furthermore, the effects of pH and dissolved oxygen （DO） on inorganic-N removal were examined. Under the condition of MLSS at 1.56-2.35 g/L, BODs/ammonia nitrogen （NH4＋-N） at 1.0, pH at 7.0-7.5, and DO at 1.0-2.0 mg/L, the removal efficiencies of NH4^＋-N and inorganic-N were 91.5% and 70.0%, respectively, in the AEC-MBR. The cost of addition of alkaline reagent was approximately 0.5-1.5 RMB yuan/m^3, and the energy consumption was approximately 0.72 kWh/m^3 at the flux of 8 L/（m^2-h）.展开更多
The sustainable recovery and utilization of sludge bioenergy within a circular economy context has drawn increasing attention,but there is currently a shortage of reliable technology.This study presents an innovative ...The sustainable recovery and utilization of sludge bioenergy within a circular economy context has drawn increasing attention,but there is currently a shortage of reliable technology.This study presents an innovative biotechnology based on free nitrous acid(FNA)to realize sustainable organics recovery from waste activated sludge(WAS)in-situ,driving efficient nitrogen removal from ammonia rich mature landfill leachate by integrating partial nitrification,fermentation,and denitrification process(PN/DN-F/DN).First,ammonia((1708.5±142.9)mg·L^(-1))in mature landfill leachate is oxidized to nitrite in the aerobic stage of a partial nitrification coupling denitrification(PN/DN)sequencing batch reactor(SBR),with nitrite accumulation ratio of 95.4%±2.5%.Then,intermediate effluent(NO_(2)^(-)-N=(1196.9±184.2)mg·L^(-1))of the PN/DN-SBR,along with concentrated WAS(volatile solids(VSs)=(15119.8±2484.2)mg·L^(-1)),is fed into an anoxic reactor for fermentation coupling denitrification process(F/DN).FNA,the protonated form of nitrite,degrades organics in the WAS to the soluble fraction by the biocidal effect,and the released organics are utilized by denitrifiers to drive NOx-reduction.An ultra-fast sludge reduction rate of 4.89 kg·m^(-3)·d^(-1) and nitrogen removal rate of 0.46 kg·m^(-3)·d^(-1) were realized in the process.Finally,F/DN-SBR effluent containing organics is refluxed to PN/DN-SBR for secondary denitrification in the post anoxic stage.After 175 d operation,an average of 19350.6 mg chemical oxygen demand organics were recovered per operational cycle,with 95.2%nitrogen removal and 53.4%sludge reduction.PN/DN-F/DN is of great significance for promoting a paradigm transformation from energy consumption to energy neutral,specifically,the total benefit in equivalent terms of energy was 291.8 kW·h·t^(-1) total solid.展开更多
In this paper, the reactive yellow 14 dye solution was removed from aqueous solution in the presence of commercial ZnO (mean crystallite size is 44.116 nm) under the UV A light. The decolourization of dye process was ...In this paper, the reactive yellow 14 dye solution was removed from aqueous solution in the presence of commercial ZnO (mean crystallite size is 44.116 nm) under the UV A light. The decolourization of dye process was obeyed to pseudo-first orderkinetics. The optimum conditions of decolourization for this dye such as: initial dye concentration 50 mg/L, best dose of ZnO 350 mg/100mL and initial pH of aqueous solution of dye 6.75 were studied. Activation energies for dye were found to be 27.244 kJmol<sup>-1</sup>. The photoreaction process was observed to be endothermic reaction and less randomness.展开更多
基金Project supported by the Hi-Tech Research and Development Program (863) of China (No. 2002AA601220)
文摘Removal of inorganic nitrogen （inorganic-N） from toilet wastewater, using a pilot-scale airlift external circulation membrane bioreactor （AEC-MBR） was studied. The results showed that the use of AEC-MBR with limited addition of alkaline reagents and volumetric loading rates of inorganic-N of 0.19-0.40 kg inorganic-N/（m^3·d） helped achieve the desired nitrification and denitrification. Furthermore, the effects of pH and dissolved oxygen （DO） on inorganic-N removal were examined. Under the condition of MLSS at 1.56-2.35 g/L, BODs/ammonia nitrogen （NH4＋-N） at 1.0, pH at 7.0-7.5, and DO at 1.0-2.0 mg/L, the removal efficiencies of NH4^＋-N and inorganic-N were 91.5% and 70.0%, respectively, in the AEC-MBR. The cost of addition of alkaline reagent was approximately 0.5-1.5 RMB yuan/m^3, and the energy consumption was approximately 0.72 kWh/m^3 at the flux of 8 L/（m^2-h）.
基金supported by the Beijing Natural Science Foundation (8222040)Key Program of National Natural Science Foundation of China (52131004)+4 种基金Young Elite Scientists Sponsorship Program by China association for science and technology (CAST,YESS20220508)Young Elite Scientists Sponsorship Program by Beijing Association for Science and Technology (BAST,BYESS2023183)Innovation and Entrepreneurship Leading Team Project in Guangzhou (CYLJTD-201607)Key Research and Developmental Program of Shandong Province (2020CXGC011404)Cultivating Fund of Faculty of Environment and Life,Beijing University of Technology (PY202302).
文摘The sustainable recovery and utilization of sludge bioenergy within a circular economy context has drawn increasing attention,but there is currently a shortage of reliable technology.This study presents an innovative biotechnology based on free nitrous acid(FNA)to realize sustainable organics recovery from waste activated sludge(WAS)in-situ,driving efficient nitrogen removal from ammonia rich mature landfill leachate by integrating partial nitrification,fermentation,and denitrification process(PN/DN-F/DN).First,ammonia((1708.5±142.9)mg·L^(-1))in mature landfill leachate is oxidized to nitrite in the aerobic stage of a partial nitrification coupling denitrification(PN/DN)sequencing batch reactor(SBR),with nitrite accumulation ratio of 95.4%±2.5%.Then,intermediate effluent(NO_(2)^(-)-N=(1196.9±184.2)mg·L^(-1))of the PN/DN-SBR,along with concentrated WAS(volatile solids(VSs)=(15119.8±2484.2)mg·L^(-1)),is fed into an anoxic reactor for fermentation coupling denitrification process(F/DN).FNA,the protonated form of nitrite,degrades organics in the WAS to the soluble fraction by the biocidal effect,and the released organics are utilized by denitrifiers to drive NOx-reduction.An ultra-fast sludge reduction rate of 4.89 kg·m^(-3)·d^(-1) and nitrogen removal rate of 0.46 kg·m^(-3)·d^(-1) were realized in the process.Finally,F/DN-SBR effluent containing organics is refluxed to PN/DN-SBR for secondary denitrification in the post anoxic stage.After 175 d operation,an average of 19350.6 mg chemical oxygen demand organics were recovered per operational cycle,with 95.2%nitrogen removal and 53.4%sludge reduction.PN/DN-F/DN is of great significance for promoting a paradigm transformation from energy consumption to energy neutral,specifically,the total benefit in equivalent terms of energy was 291.8 kW·h·t^(-1) total solid.
文摘In this paper, the reactive yellow 14 dye solution was removed from aqueous solution in the presence of commercial ZnO (mean crystallite size is 44.116 nm) under the UV A light. The decolourization of dye process was obeyed to pseudo-first orderkinetics. The optimum conditions of decolourization for this dye such as: initial dye concentration 50 mg/L, best dose of ZnO 350 mg/100mL and initial pH of aqueous solution of dye 6.75 were studied. Activation energies for dye were found to be 27.244 kJmol<sup>-1</sup>. The photoreaction process was observed to be endothermic reaction and less randomness.
