[Objective] This study aimed to isolate and screen black-spot-resistant en- dophytic fungi strains. [Method] Various species of healthy Rosa chinensis were col- lected from Xi'an, Xianyang, Baoji and Weinan City in S...[Objective] This study aimed to isolate and screen black-spot-resistant en- dophytic fungi strains. [Method] Various species of healthy Rosa chinensis were col- lected from Xi'an, Xianyang, Baoji and Weinan City in Shaanxi Province. Endophytic fungi was isolated from stems and leaves, and purified by 2-3 times of inoculation to screen endophytic fungi antagonistic to Marssonina rosae with modified punching method. [Result] Samples collected from Xianyang exhibited the highest colonization rate and isolation rate; endophytic fungi strains isolated from stems presented the highest colonization rate and isolation rate compared with leaves. A total of 67 en- dophytic fungi strains were isolated from Rosa chinensis, including 3 black spot-re- sistant strains which were all derived from Baoji. [Conclusion] This study laid the foundation for further screening candidate strains of biocontrol fungi and environ- ment-friendly fungal biological control.展开更多
Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among...Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated.To determine the altitudinal patterns of above-/below-ground carbon allocation,we measured the root biomass and estimated the above-ground biomass(AGB) in a subalpine forest,treeline forest,alpine shrub,and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet.The AGB strongly declined with increasing elevation,which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain.The fine root biomass(FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest,whereas the coarse root biomass changed little with increasing altitudes,which led to a stable below-ground biomass(BGB) value across altitudes.Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland.Consequently,the root toshoot biomass ratio increased sharply with altitude,which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra.Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones,which should be considered when estimating carbon dynamics with shifting treelines.展开更多
A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological an...A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.展开更多
With continuous and slow oxygen-release characteristic, calcium peroxide (CaO2) has been a new source of supplying oxygen for aerobic microbes in bioremediation of contaminated groundwater. Batch experiments were co...With continuous and slow oxygen-release characteristic, calcium peroxide (CaO2) has been a new source of supplying oxygen for aerobic microbes in bioremediation of contaminated groundwater. Batch experiments were conducted to evaluate the oxygen-release rate of CaO2reacting with water, the regulation of high pH, as well as the growth of mixed aerobic microbes in the medium containing CaO2, The results show that the oxygen-release process of CaO2 comprises three phases. In the first phase, dissolved oxygen levels of water increased sharply, and average oxygen-release rates increased as the adding weight of CaO2 increased, However, the rates almost kept invariable in the latter phases and were approximately 0.48; and 0. 084 mg O2·h^-1, respectively. As the necessary components of medium, potassium dihydrogen phosphate (KH2PO4 ) and amrnoniurn sulphate ((NH4)2SO4) at a certain ratio could regulate pH caused by CaO2 from 12, 1 to the range of 6.5 -8.5, which is helpful for microbial growth, In addition, diauxic growth curve observed in the medium containing CaO2 suggested that the growth of mixed aerobic microbes could be stimulated by the addition of CaO2.展开更多
The biodegradability of wastewater containing priority pollutant pesticideVydine or triadimenol(C14H18CLN3O2) in different bio-reactor configurations was investigated.Two laboratory scale biological reactors were em...The biodegradability of wastewater containing priority pollutant pesticideVydine or triadimenol(C14H18CLN3O2) in different bio-reactor configurations was investigated.Two laboratory scale biological reactors were employed:one reactor under aerobic condition and the other under anaerobic condition.The aerobic reactor was operated at an ambient temperature(22±2) °C,while the anaerobic reactor was run in the lower mesophilic range(30±2) °C.The effect of pesticide concentration,hydraulic retention time(HRT) ,and co-substrate on the treatment process was explored,using glucose as a supplemental carbon substrate.More than 96%pesticide was removed after an acclimation period of approximately 172 d(aerobic) and 230 d(anaerobic) .The aerobic reactor achieved complete Vydine utilization at feed concentrations up to 25 mg·L^-1 .On the other hand,the anaerobic reactor was able to degrade 25 mg·L^-1 of Vydine.Moreover,glucose was consumed first throughout the experiment in a sequential utilization pattern.The combination of anaerobic and aerobic biological processes yielded higher biomass concentration and lower retention time than individual units.The biomass in the combined reactors was first acclimated with the corresponding pesticide.Then,the target pesticide,at a concentration of 25 mg·L^-1,was sequentially treated in a semi batch mode in the reactors.HRT studies showed that 24 h HRT of aerobic and 12 h HRT of anaerobic were the optimum combination for the treatment of simulated wastewater containing Vydine,which produced Vydine effluent at concentration below 0.1 mg·L^-1 .The optimum ratio of substrate(Vydine) to co-substrate(glucose) was 1︰100.展开更多
Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the se...Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently,the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d,generating two main degraded products:mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP,the dominant family in the final enrichment culture is clustered with the Comamonas sp.,the remaining are affiliated with Sphingomonas sp.,Hydrogenophaga sp.,Rhizobium sp.,and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.展开更多
In this study, chicken manure and Caragana korshinskii Kom powder were used as the main raw materials with different amounts of biochar added to test four aerobic composting treatment groups A, B, C and D with laborat...In this study, chicken manure and Caragana korshinskii Kom powder were used as the main raw materials with different amounts of biochar added to test four aerobic composting treatment groups A, B, C and D with laboratory composting fermenters and testing apparatus, and new insight into biochar’s nitrogen conservation mechanism was gotten, based on the experimental data and related exploration such as the physical and chemical properties of the final products, the changing interactions among nutrient elements and other elements, and the relationship between substrate degradation and the amount of biochar used as well as the best formula for reducing ammonia emission. The results showed that the proper proportion of the added biochar to the other elements was conducive to less ammonia emission and nitrogen loss during the aerobic composting. The composting effect of Treatment C (biochar at 20%) was the optimal in the test, where in the composting temperature rose the most rapid and the earliest to the maximum temperature 52.5℃, with the least nitrogen loss. An effective, safe and high-quality resource utilization of chicken manure was established through the aerobic composting with reasonable material mixture proportion.展开更多
A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of...A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.展开更多
The article assesses the determinants of farmers' decisions to participate in organic farming, eliciting farmers risk preferences and empirically analysing farmer's sources of risk and risk management strategies. Th...The article assesses the determinants of farmers' decisions to participate in organic farming, eliciting farmers risk preferences and empirically analysing farmer's sources of risk and risk management strategies. The ordered probit results indicate that older farmers, who are less risk averse and reside in the sub-ward Ogagwini, Ezigani and Hwayi were more likely to be certified organic. Similarly, the propensity to adopt organic farming is positively correlated to household size, livestock ownership, asset base and tenure security. At higher pay-offs, farmers were intermediate to moderately risk-averse, with little variation according to personal characteristics. In general, price, production and financial risks were perceived as important sources of risk. Seven principal components, explaining 66.13% of the variation were extracted. Socio-economic factors having a significant effect on the various sources of risk were age, gender, education, location, information access and risk taking ability. The dimensions of risk strategies were named as diversification, precautionary savings and social networks. Results provide practical insights for policy changes relevant in motivating the adoption of organic practices, increasing smallholder farmers' capacity to manage risk and driving growth in the organic food market.展开更多
Lead(Pb) and its compounds are common pollutants in industrial wastewaters.To develop appropriate Pb 2+ treatment technologies,aerobic granules(AG) and bacterial alginates(BA) were studied as alternative biosorbents t...Lead(Pb) and its compounds are common pollutants in industrial wastewaters.To develop appropriate Pb 2+ treatment technologies,aerobic granules(AG) and bacterial alginates(BA) were studied as alternative biosorbents to remove Pb 2+ from aqueous solutions.The biosorption mechanism of AG and BA were further analyzed to determine which functional groups in AG and BA are active in Pb 2+ biosorption.In this paper,the Pb 2+ biosorption behavior of AG and BA was respectively investigated in batch experiments from the perspectives of the initial pH,contact time,and initial Pb 2+ concentration.The results showed that biosorption of Pb 2+ by AG and BA occurred within 60min at the initial Pb 2+ concentrations(0 150 mg L-1).The actual saturated Pb 2+ biosorption capability of AG was 101.97 mg g-1(dry weight of aerobic granular biomass).When the initial pH was 5,the biosorption capability of AG and BA was highest at the initial Pb 2+ concentrations(0 20mg L-1).During the process of Pb 2+ biosorption,K +,Ca 2+,and Mg 2+ were released.The Ion Chromatography(IC) and Fourier Transform Infrared Spectroscopy(FTIR) further highlighted the main role of ion exchange between Ca 2+ and Pb 2+ and sequestration of Pb 2+ with carboxyl(-COO) of AG and BA.This analogical analysis verifies that BA is responsible for biosorption of Pb 2+ by AG.At the same optimal pH,AG cultivated with different carbon source has different Pb 2+ biosorption capacity.The Pb 2+ biosorption by AG with sodium acetate as the sole carbon source is higher than AG with glucose as carbon source.展开更多
Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-p...Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-philic aerobic digestion(ATAD) . Based on an Arrhenius-type equation,an empirical model was developed to corre-late the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25 °C to a maximum temperature of 65 °C. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and-0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal effi-ciency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.展开更多
Based on the coal demand under the 1.5 ℃ scenario, the amount of coal production in China was estimated in this study. According to the mutual relationship between the factors influencing coal production, an economet...Based on the coal demand under the 1.5 ℃ scenario, the amount of coal production in China was estimated in this study. According to the mutual relationship between the factors influencing coal production, an econometric model was constructed based on simultaneous equations, and the synergistic effect of each factor on the coal industry was estimated under the 1.5 ℃ scenario. Then, predictions were respectively made in the five aspects: coal production, coal science and technology progress, employment number, safe production level, and occupational health level, in different scenarios from 2016 to 2050. The results showed that before 2040, the comprehensive negative effect of the 1.5 ℃ situation is more than or equals to the positive effect. The 1.5 ℃ scenario has the biggest negative impact on employment, whose solution should be the focus. By 2050, the positive effects of the 1.5℃ scenario exceed the negative effect because of the enhancement in technical level and in the attention given to the whole production. Safety is improved, and health defects decline and the most obvious positive effect is on the ecological environment. The decrease of coal production will reduce the ecological environmental damage and significantly improve the ecological environment. In general, the prediction of 1.5 ℃ scenario promotes the increase of scientific production capacity and promotes the orderly development of coal. It has strengthened the safety and health protection degree, made the coal industry more efficient and competitive, and avoided or reduced the impact of coal development on the ecological environment and achieved environmental friendliness. However, the 1.5 ℃ situation also increases the employment pressure of the society, which affects the economic development of the major coal producing areas, but the situation can be overcome through the transformation and upgrading of the region. Finally, the impacts of various factors under the 1.5 ℃ scenario were evaluated through a unified comparison of the synergistic effect monetization using the cost and payment willingness methods. Based on the research results, suggestions on the regulation of coal production were proposed relating to resettlement of workers, protection of the ecological environment, and improvement of workers' health.展开更多
According to the characteristics of ecosystem and concept of the ecosystem in mining area, the index system of the ecosystem health in mining area was set up, and the evaluation standard was established. Aiming at the...According to the characteristics of ecosystem and concept of the ecosystem in mining area, the index system of the ecosystem health in mining area was set up, and the evaluation standard was established. Aiming at the complexion in which the information lost in index ration, the matter element method was put forward to evaluate the ecosystem health in mining area. Making use of the model set up, the weight was built up by the method of index number heavy, the matter element, clas- sical field, and limit field were set up. The rating hierarchy was calculated by relating function. As a case study in the mining area of Pingyangsi Town, the results show that the ecosystem is good and sustainable from 2003 to 2006, but the healthy degree is not high, and some indexes have depravation.展开更多
Bioflocculants have received increasing attention in research because they are low cost,non-toxic,biodegradable,operationally simple and useful in many water and wastewater treatment applications.In this study,we focu...Bioflocculants have received increasing attention in research because they are low cost,non-toxic,biodegradable,operationally simple and useful in many water and wastewater treatment applications.In this study,we focused mainly on the screening of the flocculant-producing strain and its application in oily wastewater treatment.Bacteria strain B-6-1 was isolated by the pyridine screening method.UPC-1 reagent produced by B-6-1 had efficient flocculating activity.It was deduced that the main component of UPC-1 reagent was polysaccharide through purification and analysis.The influence of dosage of reagent,pH value,temperature and oil concentration on the flocculation effect of UPC-1 reagent was investigated.展开更多
An eco-friendly method for the extracellular synthesis of silver nanoparticles(AgNPs) using aqueous Araza fruit extract and their antioxidant activity was investigated. It was observed that UV–Vis absorption peak i...An eco-friendly method for the extracellular synthesis of silver nanoparticles(AgNPs) using aqueous Araza fruit extract and their antioxidant activity was investigated. It was observed that UV–Vis absorption peak is dependent on various parameters such as pH, temperature, and change of time. The initial appearance of the yellow color with intense surface plasmon bands at 430-450 nm, then transmission electron microscopy, scanning electron microscopy and X-ray diffraction analysis revealed the formation of 15-45 nm sized, spherical and crystalline Ag NPs. Fourier transform infrared spectroscopy depicted that malic acid, citric acid, and carotenoids of Araza fruit involved in the synthesis of Ag NPs. In addition, the surface modified AgNPs(77.42%, 1mL) showed nearly double antioxidant efficiency than Araza fruit extract(35.30%, 1 mL) against 1, 1-diphenyl-2-picrylhydrazyl. The present study highlights the possibility of using the Araza fruit to synthesize AgNPs, which could be used effectively in the present and future antioxidant agent.展开更多
Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused py...Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused pyranopyrazole reacted with halo alcohols led to the formation of new scaffolds from fused pyranopyrazole derivatives. All newly prepared compounds are characterized spectroscopically.展开更多
基金Supported by National Natural Science Foundation of China(No.31000144)Project of Shaanxi Provincial Science and Technology Department(No.2012JQ3017)+1 种基金Project of Xi'an Science and Technology Bureau[NC1206(3)]Project of Education Department of Shaanxi Provincial Government(No.12JK1106)~~
文摘[Objective] This study aimed to isolate and screen black-spot-resistant en- dophytic fungi strains. [Method] Various species of healthy Rosa chinensis were col- lected from Xi'an, Xianyang, Baoji and Weinan City in Shaanxi Province. Endophytic fungi was isolated from stems and leaves, and purified by 2-3 times of inoculation to screen endophytic fungi antagonistic to Marssonina rosae with modified punching method. [Result] Samples collected from Xianyang exhibited the highest colonization rate and isolation rate; endophytic fungi strains isolated from stems presented the highest colonization rate and isolation rate compared with leaves. A total of 67 en- dophytic fungi strains were isolated from Rosa chinensis, including 3 black spot-re- sistant strains which were all derived from Baoji. [Conclusion] This study laid the foundation for further screening candidate strains of biocontrol fungi and environ- ment-friendly fungal biological control.
基金supported by the National Natural Science Foundation of China (41561011)the Natural Science Foundation of Jiangxi Province, China (20151BAB213029)
文摘Under conditions of a warmer climate,the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems.However,the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated.To determine the altitudinal patterns of above-/below-ground carbon allocation,we measured the root biomass and estimated the above-ground biomass(AGB) in a subalpine forest,treeline forest,alpine shrub,and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet.The AGB strongly declined with increasing elevation,which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain.The fine root biomass(FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest,whereas the coarse root biomass changed little with increasing altitudes,which led to a stable below-ground biomass(BGB) value across altitudes.Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland.Consequently,the root toshoot biomass ratio increased sharply with altitude,which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra.Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones,which should be considered when estimating carbon dynamics with shifting treelines.
基金Project(30770388) supported by the National Natural Science Foundation of China
文摘A gram negative bacterium,named JDC-16,which can grow well on the substrate of phthalic acid esters(PAEs) as the sole source of carbon and energy,was isolated from river sludge.Based on the morphology,physiological and biochemical properties and analysis of 16S rRNA gene sequence,it was preliminarily identified belonging to the genus Acinetobacter.The result of substrates utilization range indicates that strain JDC-16 can utilize a variety of phthalates except for diisononyl phthalate(DINP) .The degradation tests using diethyl phthalate(DEP) as the model compound show that the optimal pH and temperature for DEP degradation by Acinetobacter sp.JDC-16 is 8.0 and 35℃,respectively.Meanwhile,degradation kinetics under various initial concentrations of DEP reveals that substrate depletion curves fit well with the modified Gompertz model with high correlation coefficient(R 2 >0.99) .Furthermore,the substrate induction test indicates that DEP-induction can apparently shorten the lag phase and enhance the degradation rate.This work highlights the potential of this isolate for bioremediation of phthalates-contaminated environments.
基金Supported by National Natural Science Foundation of China (No. 20276048).
文摘With continuous and slow oxygen-release characteristic, calcium peroxide (CaO2) has been a new source of supplying oxygen for aerobic microbes in bioremediation of contaminated groundwater. Batch experiments were conducted to evaluate the oxygen-release rate of CaO2reacting with water, the regulation of high pH, as well as the growth of mixed aerobic microbes in the medium containing CaO2, The results show that the oxygen-release process of CaO2 comprises three phases. In the first phase, dissolved oxygen levels of water increased sharply, and average oxygen-release rates increased as the adding weight of CaO2 increased, However, the rates almost kept invariable in the latter phases and were approximately 0.48; and 0. 084 mg O2·h^-1, respectively. As the necessary components of medium, potassium dihydrogen phosphate (KH2PO4 ) and amrnoniurn sulphate ((NH4)2SO4) at a certain ratio could regulate pH caused by CaO2 from 12, 1 to the range of 6.5 -8.5, which is helpful for microbial growth, In addition, diauxic growth curve observed in the medium containing CaO2 suggested that the growth of mixed aerobic microbes could be stimulated by the addition of CaO2.
文摘The biodegradability of wastewater containing priority pollutant pesticideVydine or triadimenol(C14H18CLN3O2) in different bio-reactor configurations was investigated.Two laboratory scale biological reactors were employed:one reactor under aerobic condition and the other under anaerobic condition.The aerobic reactor was operated at an ambient temperature(22±2) °C,while the anaerobic reactor was run in the lower mesophilic range(30±2) °C.The effect of pesticide concentration,hydraulic retention time(HRT) ,and co-substrate on the treatment process was explored,using glucose as a supplemental carbon substrate.More than 96%pesticide was removed after an acclimation period of approximately 172 d(aerobic) and 230 d(anaerobic) .The aerobic reactor achieved complete Vydine utilization at feed concentrations up to 25 mg·L^-1 .On the other hand,the anaerobic reactor was able to degrade 25 mg·L^-1 of Vydine.Moreover,glucose was consumed first throughout the experiment in a sequential utilization pattern.The combination of anaerobic and aerobic biological processes yielded higher biomass concentration and lower retention time than individual units.The biomass in the combined reactors was first acclimated with the corresponding pesticide.Then,the target pesticide,at a concentration of 25 mg·L^-1,was sequentially treated in a semi batch mode in the reactors.HRT studies showed that 24 h HRT of aerobic and 12 h HRT of anaerobic were the optimum combination for the treatment of simulated wastewater containing Vydine,which produced Vydine effluent at concentration below 0.1 mg·L^-1 .The optimum ratio of substrate(Vydine) to co-substrate(glucose) was 1︰100.
基金Project(50621063) supported by the National Nature Science Foundation of ChinaProject(NCET-06-0691) supported by the Program for New Century Excellent Talents in University
文摘Di-n-butyl phthalate (DBP),one of phthalate acid esters (PAEs),was investigated to determine its biodegradation rate using Xiangjiang River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded products were analyzed by GC/MS. Subsequently,the microbial diversity of the enrichment culture was analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded after merely 3 d,generating two main degraded products:mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month enrichment period under the pressure of DBP,the dominant family in the final enrichment culture is clustered with the Comamonas sp.,the remaining are affiliated with Sphingomonas sp.,Hydrogenophaga sp.,Rhizobium sp.,and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment.
基金Supported by Science and Technology Key Program of Shanxi Province(20150311016-3)~~
文摘In this study, chicken manure and Caragana korshinskii Kom powder were used as the main raw materials with different amounts of biochar added to test four aerobic composting treatment groups A, B, C and D with laboratory composting fermenters and testing apparatus, and new insight into biochar’s nitrogen conservation mechanism was gotten, based on the experimental data and related exploration such as the physical and chemical properties of the final products, the changing interactions among nutrient elements and other elements, and the relationship between substrate degradation and the amount of biochar used as well as the best formula for reducing ammonia emission. The results showed that the proper proportion of the added biochar to the other elements was conducive to less ammonia emission and nitrogen loss during the aerobic composting. The composting effect of Treatment C (biochar at 20%) was the optimal in the test, where in the composting temperature rose the most rapid and the earliest to the maximum temperature 52.5℃, with the least nitrogen loss. An effective, safe and high-quality resource utilization of chicken manure was established through the aerobic composting with reasonable material mixture proportion.
基金Supported by the Major Science and Technology Program for Water Pollution Contro and Treatment-Crucial Technology Research and Engineering Sample Subject on Municipa Wastewater Treatment Process Updated to Higher Drainage Standard(2008ZX07317-02)Wuhan Water Pollution Control and the Water Environment Administer Technology and Synthetic Sample Project in Cities and Towns(2008ZX07317)
文摘A pilot-scale modified carbon source division anaerobic anoxic oxic(AAO) process with pre-concentration of returned activated sludge(RAS) was proposed in this study for the enhanced biological nutrient removal(BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60% and 50%, respectively, with an inner recycling ratio of 100% under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L-1with a removal efficiency of 63% and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.
文摘The article assesses the determinants of farmers' decisions to participate in organic farming, eliciting farmers risk preferences and empirically analysing farmer's sources of risk and risk management strategies. The ordered probit results indicate that older farmers, who are less risk averse and reside in the sub-ward Ogagwini, Ezigani and Hwayi were more likely to be certified organic. Similarly, the propensity to adopt organic farming is positively correlated to household size, livestock ownership, asset base and tenure security. At higher pay-offs, farmers were intermediate to moderately risk-averse, with little variation according to personal characteristics. In general, price, production and financial risks were perceived as important sources of risk. Seven principal components, explaining 66.13% of the variation were extracted. Socio-economic factors having a significant effect on the various sources of risk were age, gender, education, location, information access and risk taking ability. The dimensions of risk strategies were named as diversification, precautionary savings and social networks. Results provide practical insights for policy changes relevant in motivating the adoption of organic practices, increasing smallholder farmers' capacity to manage risk and driving growth in the organic food market.
基金supported by the National Natural Science Foundation of China (No. 30570339)the Key Science & Technology Project of the Ministry of Education China (No.106105)
文摘Lead(Pb) and its compounds are common pollutants in industrial wastewaters.To develop appropriate Pb 2+ treatment technologies,aerobic granules(AG) and bacterial alginates(BA) were studied as alternative biosorbents to remove Pb 2+ from aqueous solutions.The biosorption mechanism of AG and BA were further analyzed to determine which functional groups in AG and BA are active in Pb 2+ biosorption.In this paper,the Pb 2+ biosorption behavior of AG and BA was respectively investigated in batch experiments from the perspectives of the initial pH,contact time,and initial Pb 2+ concentration.The results showed that biosorption of Pb 2+ by AG and BA occurred within 60min at the initial Pb 2+ concentrations(0 150 mg L-1).The actual saturated Pb 2+ biosorption capability of AG was 101.97 mg g-1(dry weight of aerobic granular biomass).When the initial pH was 5,the biosorption capability of AG and BA was highest at the initial Pb 2+ concentrations(0 20mg L-1).During the process of Pb 2+ biosorption,K +,Ca 2+,and Mg 2+ were released.The Ion Chromatography(IC) and Fourier Transform Infrared Spectroscopy(FTIR) further highlighted the main role of ion exchange between Ca 2+ and Pb 2+ and sequestration of Pb 2+ with carboxyl(-COO) of AG and BA.This analogical analysis verifies that BA is responsible for biosorption of Pb 2+ by AG.At the same optimal pH,AG cultivated with different carbon source has different Pb 2+ biosorption capacity.The Pb 2+ biosorption by AG with sodium acetate as the sole carbon source is higher than AG with glucose as carbon source.
基金Supported by the Doctoral Foundation of Northeast Dianli University (BSJXM-200814)Foundations of Bureau of Jilin Province (2008424)
文摘Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-philic aerobic digestion(ATAD) . Based on an Arrhenius-type equation,an empirical model was developed to corre-late the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25 °C to a maximum temperature of 65 °C. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and-0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal effi-ciency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.
文摘Based on the coal demand under the 1.5 ℃ scenario, the amount of coal production in China was estimated in this study. According to the mutual relationship between the factors influencing coal production, an econometric model was constructed based on simultaneous equations, and the synergistic effect of each factor on the coal industry was estimated under the 1.5 ℃ scenario. Then, predictions were respectively made in the five aspects: coal production, coal science and technology progress, employment number, safe production level, and occupational health level, in different scenarios from 2016 to 2050. The results showed that before 2040, the comprehensive negative effect of the 1.5 ℃ situation is more than or equals to the positive effect. The 1.5 ℃ scenario has the biggest negative impact on employment, whose solution should be the focus. By 2050, the positive effects of the 1.5℃ scenario exceed the negative effect because of the enhancement in technical level and in the attention given to the whole production. Safety is improved, and health defects decline and the most obvious positive effect is on the ecological environment. The decrease of coal production will reduce the ecological environmental damage and significantly improve the ecological environment. In general, the prediction of 1.5 ℃ scenario promotes the increase of scientific production capacity and promotes the orderly development of coal. It has strengthened the safety and health protection degree, made the coal industry more efficient and competitive, and avoided or reduced the impact of coal development on the ecological environment and achieved environmental friendliness. However, the 1.5 ℃ situation also increases the employment pressure of the society, which affects the economic development of the major coal producing areas, but the situation can be overcome through the transformation and upgrading of the region. Finally, the impacts of various factors under the 1.5 ℃ scenario were evaluated through a unified comparison of the synergistic effect monetization using the cost and payment willingness methods. Based on the research results, suggestions on the regulation of coal production were proposed relating to resettlement of workers, protection of the ecological environment, and improvement of workers' health.
文摘According to the characteristics of ecosystem and concept of the ecosystem in mining area, the index system of the ecosystem health in mining area was set up, and the evaluation standard was established. Aiming at the complexion in which the information lost in index ration, the matter element method was put forward to evaluate the ecosystem health in mining area. Making use of the model set up, the weight was built up by the method of index number heavy, the matter element, clas- sical field, and limit field were set up. The rating hierarchy was calculated by relating function. As a case study in the mining area of Pingyangsi Town, the results show that the ecosystem is good and sustainable from 2003 to 2006, but the healthy degree is not high, and some indexes have depravation.
基金Funded by the scientific research and technological development project of China national petroleum corporation(No. 2006A50302)
文摘Bioflocculants have received increasing attention in research because they are low cost,non-toxic,biodegradable,operationally simple and useful in many water and wastewater treatment applications.In this study,we focused mainly on the screening of the flocculant-producing strain and its application in oily wastewater treatment.Bacteria strain B-6-1 was isolated by the pyridine screening method.UPC-1 reagent produced by B-6-1 had efficient flocculating activity.It was deduced that the main component of UPC-1 reagent was polysaccharide through purification and analysis.The influence of dosage of reagent,pH value,temperature and oil concentration on the flocculation effect of UPC-1 reagent was investigated.
基金funded by the Prometeo Project of the National Secretariat of Higher Education, Science, Technology and Innovation (SENESCYT), Ecuador
文摘An eco-friendly method for the extracellular synthesis of silver nanoparticles(AgNPs) using aqueous Araza fruit extract and their antioxidant activity was investigated. It was observed that UV–Vis absorption peak is dependent on various parameters such as pH, temperature, and change of time. The initial appearance of the yellow color with intense surface plasmon bands at 430-450 nm, then transmission electron microscopy, scanning electron microscopy and X-ray diffraction analysis revealed the formation of 15-45 nm sized, spherical and crystalline Ag NPs. Fourier transform infrared spectroscopy depicted that malic acid, citric acid, and carotenoids of Araza fruit involved in the synthesis of Ag NPs. In addition, the surface modified AgNPs(77.42%, 1mL) showed nearly double antioxidant efficiency than Araza fruit extract(35.30%, 1 mL) against 1, 1-diphenyl-2-picrylhydrazyl. The present study highlights the possibility of using the Araza fruit to synthesize AgNPs, which could be used effectively in the present and future antioxidant agent.
文摘Four components have been reacted in water and in the presence of N-morpholine yielded pyrnopyrazole as a simple substrate for novel N2-acyclonucleoside derivatives of fused pyranopyrazole. The sodium salt of fused pyranopyrazole reacted with halo alcohols led to the formation of new scaffolds from fused pyranopyrazole derivatives. All newly prepared compounds are characterized spectroscopically.