Woodchip bioreactors are an eco-friendly technology for removing nitrogen(N)pollution.However,there needs to be more clarity regarding the dissolved organicmatter(DOM)characteristics and bacterial community succession...Woodchip bioreactors are an eco-friendly technology for removing nitrogen(N)pollution.However,there needs to be more clarity regarding the dissolved organicmatter(DOM)characteristics and bacterial community succession mechanisms and their association with the N removal performance of bioreactors.The laboratory woodchip bioreactors were continuously operated for 360 days under three influent N level treatments,and the results showed that the average removal rate of TN was 45.80 g N/(m^(3)·day)when the influent N level was 100 mg N/L,which was better than 10 mg N/L and 50 mg N/L.Dynamic succession of bacterial communities in response to influent N levels and DOM characteristics was an important driver of TN removal rates.Medium to high N levels enriched a copiotroph bacterial module(Module 1)detected by network analysis,including Phenylobacterium,Xanthobacteraceae,Burkholderiaceae,Pseudomonas,and Magnetospirillaceae,carrying N-cycle related genes for denitrification and ammonia assimilation by the rapid consumption of DOM.Such a process can increase carbon limitation to stimulate local organic carbon decomposition to enrich oligotrophswith fewer N-cycle potentials(Module 2).Together,this study reveals that the compositional change ofDOMand bacterial community succession are closely related to N removal performance,providing an ecological basis for developing techniques for N-rich effluent treatment.展开更多
The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fib...The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fiber fraction proportion,andCanadian standard freeness(CSF)were determined to evaluate the effectsof pulp consistency and NaOH dosage on the refining performancesof mixed poplar and eucalypt woodchips.While the dosage of NaOHfor impregnation was maintained constant,the SEC and shive contentincreased with increasing pulp consistency.Different fractions obtainedfrom the Bauer-McNett classifier showed that higher pulp consistencycould be expected to yield more long fibers and shive in the stock.Upon increasing the NaOH dosage,the shive content and SEC reducedsignificantly.When the NaOH dosage was increased to 6%,the resultsindicated that it was difficult to reduce the shive content to less than 1%athigh pulp consistencies(25%~35%),whereas 0.18%shive fraction couldbe achieved at a medium pulp consistency(15%).展开更多
Wood from three tree species was used for making slow-releasing woodchip fertilizer. Fertilizer made from Populus tomentiglandulosa retained the highest amounts of N （29.04%）, P205 （26.03%） and K20 （16.93%）. On ...Wood from three tree species was used for making slow-releasing woodchip fertilizer. Fertilizer made from Populus tomentiglandulosa retained the highest amounts of N （29.04%）, P205 （26.03%） and K20 （16.93%）. On the other band, woodchip fertilizer made from Pinus koraiensis retained the lowest amounts of N （26.22%）, P205 （21.80%） and I（20 （14.49%）. A field experiment was performed in a 50 m^2 experimental plot at Gangwon Agricultural Research and Extension Services, Chuncheon, Korea from August to November 1999. The effects of a general fertilizer along with compost and slow releasing woodchip fertilizer without compost on the cabbage production were observed. Cabbage production parameters, such as top height, head weight, head height, head width, number of outer and inner leaves, leaf width and head length, increased in the field where Larix kaempferi woodchip fertilizer was added as a basal dose. The result showed that the woodchip fertilizer made from Pinus koraiensis had faster releasing properties compared to other woodchip fertilizers. Without adding any compost in the woodchip fertilized field, woodchip fertilizer showed a superior outcome over a general chemical fertilizer. Although the amount of woodchip fertilizer was larger compared to that of a chemical fertilizer, it increased cabbage production.展开更多
The study deals with a multi-faceted theoretical approach,symbolic,analytical and numerical,based on the chemical equilibrium assumption,addressed at predicting the performance trends of downdrafi wood-gasification pr...The study deals with a multi-faceted theoretical approach,symbolic,analytical and numerical,based on the chemical equilibrium assumption,addressed at predicting the performance trends of downdrafi wood-gasification processes so to assess the optimal ranges of input parameters,in particular the equivalence ratios,suitable to achieving the highest cold gas efficiencies whilst keeping the more the possible tar-free the produced bio-syngas.The time-steady,zero-dimensional model has been developed within MATLAB(the computing language and interactive environment from Matrix Laboratory)and solved by enforcing the constraints posed by the equilibrium constants in relation to two reactions,gas-water shift and methanation.Particular care is devoted toward verifying the real attainment of the equilibrium condition,as attested by an actual presence of products from the equilibrium reactions together with a zero difference AE between the energy flows entering and exiting the system,an issue often overlooked.With respect to other similar theoretical approaches,the numerical model,assisted by the symbolic counterpart for better interpretation and intrinsic validation of results,shows a distinct advantage in predicting rather accurately the syngas composition for varying gasification temperatures,as attested by cross comparisons with experimental data directly taken on an instrumented,dedicated,small-scale downdraft gasifier operational at DIME/SCL(the Savona Combustion Laboratory of DIME,the Dept.of Mechanical,Energy,Management and Transportation Engineering of Genova University).The behavior of cold gas efficiency clearly points out that,from an energy conversion point of view,the optimal gasification temperatures turn out comprised between 900℃and 1,000℃:this range is indeed characterized by the highest concentrations in the energy-rich syngas components CO and H2.For higher temperatures,as induced by higher air-to-fuel ratios,the progressive oxidation of above components,together with increasing nitrogen levels,would decrease the bio-syngas heat values.展开更多
The impact of different woodchips(beech,oak,pear,and apple)on the contents of heterocyclic aromatic amines(HAAs)and quality characteristics of smoked bacon was investigated.The results indicated that the contents of t...The impact of different woodchips(beech,oak,pear,and apple)on the contents of heterocyclic aromatic amines(HAAs)and quality characteristics of smoked bacon was investigated.The results indicated that the contents of total HAAs and non-polar HAAs in beech-and oak-smoked bacon were lower than that in pear-and apple-smoked bacon(P<0.05).There were no HAAs detectable in control(non-smoking)sample.The smoking process promoted the formation of free amino acids(FAA)in the smoked bacon.The total contents of FAA in beech-and oak-smoked bacon were higher than these in the pear-and apple-smoked bacons(P<0.05).The beech-smoked bacon had the highest L^(*)-value(P<0.05),and oak-smoked bacon had the lowest thiobarbituric acid-reactive substance(TBARS)value and carbonyl content(P<0.05).Additionally,woodchip types had no significant influence on a^(*)-value,b^(*)-value,moisture content,aw,T_(20),T_(21) and T_(22)(P>0.05).PCA of the HAA contents and quality characteristics could effectively differentiate that were unsmoked and smoked bacon.Therefore,woodchip types had a great influence on HAA contents and quality of smoked bacon.展开更多
Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and...Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and dry toot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of： 1 ） six types of wood media （including torrefied wood media and biochar） that could be used in a woodchip HUA versus a gravel control, and 2） providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events （53%-61% vs. 39% reductions, respectively）, and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments （mean removal efficiencies 〉 50%） was observed across the sinmlated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon （i.e., fresh woodchips exhibited 〉 70% nitrate removal）. The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.展开更多
研究了不同渗透剂对桉木化学机械法制浆性能的影响,结果表明:不同类型的渗透剂对桉木浸渍性能的影响差异较大,其中磺化琥珀酸二辛酯钠盐类渗透剂S4对桉木浸渍性能改善程度最高,渗透剂用量为0.4%时,可以使木片的吸液量和Na OH吸收率分别...研究了不同渗透剂对桉木化学机械法制浆性能的影响,结果表明:不同类型的渗透剂对桉木浸渍性能的影响差异较大,其中磺化琥珀酸二辛酯钠盐类渗透剂S4对桉木浸渍性能改善程度最高,渗透剂用量为0.4%时,可以使木片的吸液量和Na OH吸收率分别比对照样提高7.34%和9.97%。渗透剂对桉木化学机械浆的性能影响如下:浸渍段添加0.4%渗透剂S4,制取加拿大游离度(CSF)为300 m L的纸浆,可以使磨浆电耗降低10%以上,浆中的细小组分减少9个百分点以上,纤维束减少46%;纸浆的抗张强度、耐破强度及撕裂强度均有不同程度的提高,可分别提高11.4%、14.3%和15.6%,但对纸浆的白度无明显影响。展开更多
The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpr...The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpregnated woodchips from tropical plant biomass(oil palm frond and rubberwood),was developed.The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry.When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h,release was slow and steady,although the release rate was lower in distilled water than in the soil solution.展开更多
基金supported by the National Key Research and Development Program of China (Nos.2018YFE0105600 and 2020YFC1806803)the New Zealand MBIE Catalyst Fund (No.92846082).
文摘Woodchip bioreactors are an eco-friendly technology for removing nitrogen(N)pollution.However,there needs to be more clarity regarding the dissolved organicmatter(DOM)characteristics and bacterial community succession mechanisms and their association with the N removal performance of bioreactors.The laboratory woodchip bioreactors were continuously operated for 360 days under three influent N level treatments,and the results showed that the average removal rate of TN was 45.80 g N/(m^(3)·day)when the influent N level was 100 mg N/L,which was better than 10 mg N/L and 50 mg N/L.Dynamic succession of bacterial communities in response to influent N levels and DOM characteristics was an important driver of TN removal rates.Medium to high N levels enriched a copiotroph bacterial module(Module 1)detected by network analysis,including Phenylobacterium,Xanthobacteraceae,Burkholderiaceae,Pseudomonas,and Magnetospirillaceae,carrying N-cycle related genes for denitrification and ammonia assimilation by the rapid consumption of DOM.Such a process can increase carbon limitation to stimulate local organic carbon decomposition to enrich oligotrophswith fewer N-cycle potentials(Module 2).Together,this study reveals that the compositional change ofDOMand bacterial community succession are closely related to N removal performance,providing an ecological basis for developing techniques for N-rich effluent treatment.
文摘The refining performances of mixed poplar and eucalyptwoodchips(mixture ratio 6:4)were investigated at medium and highpulp consistency via chemi-mechanical pulping(CMP).The specificrefining energy consumption(SEC),fiber fraction proportion,andCanadian standard freeness(CSF)were determined to evaluate the effectsof pulp consistency and NaOH dosage on the refining performancesof mixed poplar and eucalypt woodchips.While the dosage of NaOHfor impregnation was maintained constant,the SEC and shive contentincreased with increasing pulp consistency.Different fractions obtainedfrom the Bauer-McNett classifier showed that higher pulp consistencycould be expected to yield more long fibers and shive in the stock.Upon increasing the NaOH dosage,the shive content and SEC reducedsignificantly.When the NaOH dosage was increased to 6%,the resultsindicated that it was difficult to reduce the shive content to less than 1%athigh pulp consistencies(25%~35%),whereas 0.18%shive fraction couldbe achieved at a medium pulp consistency(15%).
文摘Wood from three tree species was used for making slow-releasing woodchip fertilizer. Fertilizer made from Populus tomentiglandulosa retained the highest amounts of N （29.04%）, P205 （26.03%） and K20 （16.93%）. On the other band, woodchip fertilizer made from Pinus koraiensis retained the lowest amounts of N （26.22%）, P205 （21.80%） and I（20 （14.49%）. A field experiment was performed in a 50 m^2 experimental plot at Gangwon Agricultural Research and Extension Services, Chuncheon, Korea from August to November 1999. The effects of a general fertilizer along with compost and slow releasing woodchip fertilizer without compost on the cabbage production were observed. Cabbage production parameters, such as top height, head weight, head height, head width, number of outer and inner leaves, leaf width and head length, increased in the field where Larix kaempferi woodchip fertilizer was added as a basal dose. The result showed that the woodchip fertilizer made from Pinus koraiensis had faster releasing properties compared to other woodchip fertilizers. Without adding any compost in the woodchip fertilized field, woodchip fertilizer showed a superior outcome over a general chemical fertilizer. Although the amount of woodchip fertilizer was larger compared to that of a chemical fertilizer, it increased cabbage production.
文摘The study deals with a multi-faceted theoretical approach,symbolic,analytical and numerical,based on the chemical equilibrium assumption,addressed at predicting the performance trends of downdrafi wood-gasification processes so to assess the optimal ranges of input parameters,in particular the equivalence ratios,suitable to achieving the highest cold gas efficiencies whilst keeping the more the possible tar-free the produced bio-syngas.The time-steady,zero-dimensional model has been developed within MATLAB(the computing language and interactive environment from Matrix Laboratory)and solved by enforcing the constraints posed by the equilibrium constants in relation to two reactions,gas-water shift and methanation.Particular care is devoted toward verifying the real attainment of the equilibrium condition,as attested by an actual presence of products from the equilibrium reactions together with a zero difference AE between the energy flows entering and exiting the system,an issue often overlooked.With respect to other similar theoretical approaches,the numerical model,assisted by the symbolic counterpart for better interpretation and intrinsic validation of results,shows a distinct advantage in predicting rather accurately the syngas composition for varying gasification temperatures,as attested by cross comparisons with experimental data directly taken on an instrumented,dedicated,small-scale downdraft gasifier operational at DIME/SCL(the Savona Combustion Laboratory of DIME,the Dept.of Mechanical,Energy,Management and Transportation Engineering of Genova University).The behavior of cold gas efficiency clearly points out that,from an energy conversion point of view,the optimal gasification temperatures turn out comprised between 900℃and 1,000℃:this range is indeed characterized by the highest concentrations in the energy-rich syngas components CO and H2.For higher temperatures,as induced by higher air-to-fuel ratios,the progressive oxidation of above components,together with increasing nitrogen levels,would decrease the bio-syngas heat values.
基金funded by the Major science and technology projects of Heilongjiang province(2020ZX07B02)the National Key Research and Development Program during the 13th Five-year Plan in China(2018YFD0401200).
文摘The impact of different woodchips(beech,oak,pear,and apple)on the contents of heterocyclic aromatic amines(HAAs)and quality characteristics of smoked bacon was investigated.The results indicated that the contents of total HAAs and non-polar HAAs in beech-and oak-smoked bacon were lower than that in pear-and apple-smoked bacon(P<0.05).There were no HAAs detectable in control(non-smoking)sample.The smoking process promoted the formation of free amino acids(FAA)in the smoked bacon.The total contents of FAA in beech-and oak-smoked bacon were higher than these in the pear-and apple-smoked bacons(P<0.05).The beech-smoked bacon had the highest L^(*)-value(P<0.05),and oak-smoked bacon had the lowest thiobarbituric acid-reactive substance(TBARS)value and carbonyl content(P<0.05).Additionally,woodchip types had no significant influence on a^(*)-value,b^(*)-value,moisture content,aw,T_(20),T_(21) and T_(22)(P>0.05).PCA of the HAA contents and quality characteristics could effectively differentiate that were unsmoked and smoked bacon.Therefore,woodchip types had a great influence on HAA contents and quality of smoked bacon.
文摘Overwintering cattle on pastures in many areas can damage the pasture and lead to impaired water quality. During these times, use ofa woodchip heavy-use area （HUA） presents advantages such as a soft, supportive, and dry toot surface for animals and protection of the pasture and pasture soils. However, woodchip HUAs can also be a centralized source of high nutrient loads due to their drainage outflows. A column study was conducted to assess the nutrient load reduction potential of： 1 ） six types of wood media （including torrefied wood media and biochar） that could be used in a woodchip HUA versus a gravel control, and 2） providing a 48 h retention time within the wood media to enhance nitrogen removal through denitrification. The woody media provided significant liquid waste volume reduction compared to the gravel in simulated events （53%-61% vs. 39% reductions, respectively）, and there may be additional liquid storage capacity in the woodchips not utilized during these rapid events. Substantial total nitrogen removal by the wood treatments （mean removal efficiencies 〉 50%） was observed across the sinmlated events, although nitrate leaching also occurred. Nitrate removal was enhanced during the 48 h retention test which showed removal was governed by availability of labile carbon （i.e., fresh woodchips exhibited 〉 70% nitrate removal）. The retention test also indicated biochar mixtures provided some of the best total phosphorus removal, but the greatest benefits across all parameters was provided by the Mixed Hardwood treatment.
文摘研究了不同渗透剂对桉木化学机械法制浆性能的影响,结果表明:不同类型的渗透剂对桉木浸渍性能的影响差异较大,其中磺化琥珀酸二辛酯钠盐类渗透剂S4对桉木浸渍性能改善程度最高,渗透剂用量为0.4%时,可以使木片的吸液量和Na OH吸收率分别比对照样提高7.34%和9.97%。渗透剂对桉木化学机械浆的性能影响如下:浸渍段添加0.4%渗透剂S4,制取加拿大游离度(CSF)为300 m L的纸浆,可以使磨浆电耗降低10%以上,浆中的细小组分减少9个百分点以上,纤维束减少46%;纸浆的抗张强度、耐破强度及撕裂强度均有不同程度的提高,可分别提高11.4%、14.3%和15.6%,但对纸浆的白度无明显影响。
基金supported by Research University Grant Scheme(RUGS)University Putra Malaysia(No.03-02-12-2293RU)
文摘The fertiliser industry faces a continuing challenge to improve the efficiency of their products,particularly of nitrogenous fertilisers,and to minimise adverse impacts.Therefore,a new slow release fertilizer,ureaimpregnated woodchips from tropical plant biomass(oil palm frond and rubberwood),was developed.The morphology of the impregnated woodchips was investigated by scanning electron microscopy and the success of impregnation of urea and nitrogen deposition into the woodchips was confirmed by energy dispersive X-ray spectrometry.When nitrogen release patterns from impregnated woodchips fertiliser were simulated using a soil solution and distilled water as leaching solutions in a static condition for 768 h,release was slow and steady,although the release rate was lower in distilled water than in the soil solution.
