Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen...Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen（C/N） ratio.A common solution is to add external carbon sources,but amount of liquid is difficult to determine.Therefore,a combined wood-chip-framework substrate（with wood,slag and gravel） as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem.Results show that the removal rate of ammonia nitrogen（NH_4~＋-N）,total nitrogen（TN） and chemical oxygen demand（COD） could reach 37.5%-85%,57.4%-86%,32.4%-78%,respectively,indicating the combined substrate could diffuse sufficient oxygen for the nitrification process（slag and gravel zone） and provide carbon source for denitrification process（wood-chip zone）.The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip,respectively.Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process,while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process.This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.展开更多
High dimensional stable particlcboards could be produced by usisng saturated steam treated wood chip at elevated pressures. Sample Particleboards were made from wood chip of Birch (Platyphylla). The component changes ...High dimensional stable particlcboards could be produced by usisng saturated steam treated wood chip at elevated pressures. Sample Particleboards were made from wood chip of Birch (Platyphylla). The component changes of steam treated wood chip were analysed by infrared. Infrared spectra demonstrated that the hemicelluloses in steam treated chip were less than those in untreated chip. This is one of the main reasons why steam treatment could improve particlcboard stability. The free radical concentration of steam treated chip surfaces was analysed by ESR spcctroscopy. The results showed that free radical concentration of treated chip surface was higher than that of untreated chip surface. The glueyncss of chip increased and particlcboard resin content decreased.展开更多
Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmenta...Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmental regulations.Consequently,there is a lack of an appropriate recycling and valorization methods of potato peel.Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach.Syngas is an important industrial intermediate to produce synthetic fuels and chemicals.To develop an ecofriendly and cost-effective valorization approach for potato peel,this study used a mixture of woody biomass(i.e.,wood chips)and potato peel to produce syngas by co-gasification using O_(2) as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software.The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency(CCE),and product gas composition(molar fraction)and lower heating value(LHV)of product gas were investigated.This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios(44.9%to 85.8%,46.5%to 76.2%,and 48.1%to 78.6%at ratios of 25:75,50:50,and 75:25,respectively,for wood chips to potato peel).While the molar fraction of H_(2) and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt%to 100 wt%(H_(2),at 42.1 mol%to 41.4 mol%;and CO at 44.0 mol%to 40.4 mol%),accompanied by a decrease of the LHV of the product gas(10.3 to 9.78 MJ·Nm^(−3)).The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.展开更多
基金supported by the National Natural Science Foundation of China(No.41401548)the Jilin Provincial Research Foundation for Basic Research,China(No.20150520151JH)the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(Nos. ES201510,and HC201622)
文摘Removal of nitrogen in wastewater before discharge into receiving water courses is an important consideration in treatment systems.However,nitrogen removal efficiency is usually limited due to the low carbon/nitrogen（C/N） ratio.A common solution is to add external carbon sources,but amount of liquid is difficult to determine.Therefore,a combined wood-chip-framework substrate（with wood,slag and gravel） as a slow-release carbon source was constructed in baffled subsurface-flow constructed wetlands to overcome the problem.Results show that the removal rate of ammonia nitrogen（NH_4~＋-N）,total nitrogen（TN） and chemical oxygen demand（COD） could reach 37.5%-85%,57.4%-86%,32.4%-78%,respectively,indicating the combined substrate could diffuse sufficient oxygen for the nitrification process（slag and gravel zone） and provide carbon source for denitrification process（wood-chip zone）.The nitrification and denitrification were determined according to the location of slag/gravel and wood-chip,respectively.Nitrogen removal was efficient at the steady phase before a shock loading using slag-wood-gravel combined substrate because of nitrification-denitrification process,while nitrogen removal was efficient under a shock loading with wood-slag-gravel combined substrate because of ANAMMOX process.This study provides a new idea for wetland treatment of high-strength nitrogen wastewater.
文摘High dimensional stable particlcboards could be produced by usisng saturated steam treated wood chip at elevated pressures. Sample Particleboards were made from wood chip of Birch (Platyphylla). The component changes of steam treated wood chip were analysed by infrared. Infrared spectra demonstrated that the hemicelluloses in steam treated chip were less than those in untreated chip. This is one of the main reasons why steam treatment could improve particlcboard stability. The free radical concentration of steam treated chip surfaces was analysed by ESR spcctroscopy. The results showed that free radical concentration of treated chip surface was higher than that of untreated chip surface. The glueyncss of chip increased and particlcboard resin content decreased.
基金funding provided through the Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery grant and as the University of Prince Edward Island start up award to Yulin Hu.
文摘Potato is the fifth largest agricultural crop in Canada and contributes to the generation of an abundant amount of potato peel.However,disposal/recycling this peel remains a challenge due to the stringent environmental regulations.Consequently,there is a lack of an appropriate recycling and valorization methods of potato peel.Gasification is an effective technology for producing syngas and an ecofriendly waste disposal approach.Syngas is an important industrial intermediate to produce synthetic fuels and chemicals.To develop an ecofriendly and cost-effective valorization approach for potato peel,this study used a mixture of woody biomass(i.e.,wood chips)and potato peel to produce syngas by co-gasification using O_(2) as the gasifying agent at a constant equivalence ratio of 0.3 using Aspen Plus simulation software.The influences of gasification temperature and wood chip/potato peel weight ratio on the carbon conversion efficiency(CCE),and product gas composition(molar fraction)and lower heating value(LHV)of product gas were investigated.This simulation indicated that a positive synergistic interaction occurs between wood chips and potato peel in co-gasification process in terms of an increase in CCE by comparing the arithmetic value and real value at all simulated wood chip to potato peel weight ratios(44.9%to 85.8%,46.5%to 76.2%,and 48.1%to 78.6%at ratios of 25:75,50:50,and 75:25,respectively,for wood chips to potato peel).While the molar fraction of H_(2) and CO decreased continuously with increase in the weight percentage of wood chips in the wood chip-potato peel mixture from 0 wt%to 100 wt%(H_(2),at 42.1 mol%to 41.4 mol%;and CO at 44.0 mol%to 40.4 mol%),accompanied by a decrease of the LHV of the product gas(10.3 to 9.78 MJ·Nm^(−3)).The study concluded that co-gasification for producing syngas is feasible and environmental-friendly option to recycle and valorize potato peel.
