A novel surface aeration configuration featured with aself-rotating and floating baffle (SRFB) and a Rushton disk turbine(DT) with a perforated disk has been developed. The SRFB, consistedof 12 fan blades twisted By a...A novel surface aeration configuration featured with aself-rotating and floating baffle (SRFB) and a Rushton disk turbine(DT) with a perforated disk has been developed. The SRFB, consistedof 12 fan blades twisted By an angle of 30 deg to the horizontalplane, is incorporated onto the impeller shaft to improve gasentrainment, bubble Breakup, mixing in a φ 154 mm agitated vessel.This new configuration is compared to the conventional DT surfaceAeration experimentally. The results suggest that the criticalimpeller speed for onset of gas entrainment is lower for The newconfiguration and it demands greater power consumption. Moreover, theSRFB system produces 30/100-168/100 Higher volumetric mass transfercoefficient per unit power input than that obtained in theconventional DT surface Aerator under the same operation conditions.展开更多
CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34...CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure （from 0.8 to 1.2 MPa） could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.展开更多
Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(...Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(30%, 60%, and 80%, dry matter) were applied to pretreat wheat straw for 7 days. The pretreated wheat straws were anaerobically digested at three loading rates(50, 65, and 80 g·L-1) to produce biogas. The results indicated that the wheat straw pretreated with 80% moisture content and 4% ammonia achieved the highest methane yield of 199.7 ml·g-1(based on per unit volatile solids loaded), with shorter digestion time(T80) of 25 days at the loading rate of 65 g·L-1compared to untreated one. The main chemical compositions of wheat straw were also analyzed. The cellulose and hemicellulose contents were decomposed by 2%-20% and 26%-42%, respectively,while the lignin content was hardly removed, cold-water and hot-water extracts were increased by 4%-44%, and12%-52%, respectively, for the ammonia-pretreated wheat straws at different moisture contents. The appropriate C/N ratio and decomposition of original chemical compositions into relatively readily biodegradable substances will improve the biodegradability and biogas yield.展开更多
This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase tri...This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase trials, divided into 3 groups. One group was the undosed controls. Test groups were given alum at dose rates of 1% and 20% respectively for two groups after an adaptation period. Clinical signs were observed together with postmortem and histopathological examinations. Chemical investigations included enzymatic, metabolic, electrolyte and hematological changes. The test rabbits demonstrated low voice, inappitence, whitish salivation, watery diarrhea and recumbence followed by emphysematous, lungs, electrolyte imbalance, renal dysfunctions, stiff focal inflammation of the empty intestines and congested liver with white spots. The control group was normal .On atomic absorption only the lungs kept residual alum, while the livers washed- out the substance ,may be via bile .Alum -dosed rabbits showed necrosis in the cortex and medulla of the kidney, emphysema in the lungs and necrosis in the hepatocytes. On evaluation of the above results, alum was considered to be toxic to Newzealand rabbits at dose rates tried.展开更多
The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a r...The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat （70 ~C or 140℃） combined with either acid （pH 2 or pH 4） or base （pH 9 or pH 11, obtained with Ca（OH）2 or NaOH）. Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70℃ did not differ from the untreated sludge, but thermal pre-treatment at 140℃ had a positive effect. Within the 70℃ thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca（OH）2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 ℃ thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca（OH）2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70℃ showed no effect, whereas, pre-treatment at 140℃ improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.展开更多
Based on the statistics from the China Statistical Yearbook （2000-2009） on environment and methods recommended by the IPCC, the amounts of greenhouse gas （GHG） emissions from domestic and industrial sewage treatme...Based on the statistics from the China Statistical Yearbook （2000-2009） on environment and methods recommended by the IPCC, the amounts of greenhouse gas （GHG） emissions from domestic and industrial sewage treatment in China are estimated for the period of 2003-2009. CO2 emissions per capita from sewage treatment plants are also analyzed. The results show that the GHG emissions from sewage treatment plants increased steadily from 2003 to 2009; N20 emissions from domestic sewage are the major source of the total GHG emissions from domestic sewage; CH4 emissions from domestic sewage increase with the greatest speed; CH4 emissions from paper and pulp industry are the major source of industrial sewage emissions; CO2 emissions per capita increase constantly from 2003 to 2009.展开更多
The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of ne...The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of new technologies for waste management such as gasification and melting treatments. The possibility to introduce in the Italian context the DMS （direct melting system） technology, designed and manufactured by Nippon Steel Engineering Co. Ltd., has been taken into account for the scope of proposed work. DMS technology consists in MSW gasification, slags melting and combustion of the syngas produced, with the consequent generation of electric energy through a steam cycle. The system minimizes environmental impact, thanks to an effective recycling of useful resources such as inert melted slags and metals, featuring high flexibility in terms of treatment capacity due to its modular design. The aim of this article is to consider different plant configurations in order to optimize the energy recovery downstream the DMS module. As a case study, landfill gas exploitation integrated in the DMS plant will be considered as a typical situation that could occur in the Italian scenario. The energetic input provided by the biogas allows improving the thermo-economic performances according to market incentives.展开更多
Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present pr...Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.展开更多
基金Supported by the National Natural Science Foundation of China (No. 29792074) and SINOPEC.
文摘A novel surface aeration configuration featured with aself-rotating and floating baffle (SRFB) and a Rushton disk turbine(DT) with a perforated disk has been developed. The SRFB, consistedof 12 fan blades twisted By an angle of 30 deg to the horizontalplane, is incorporated onto the impeller shaft to improve gasentrainment, bubble Breakup, mixing in a φ 154 mm agitated vessel.This new configuration is compared to the conventional DT surfaceAeration experimentally. The results suggest that the criticalimpeller speed for onset of gas entrainment is lower for The newconfiguration and it demands greater power consumption. Moreover, theSRFB system produces 30/100-168/100 Higher volumetric mass transfercoefficient per unit power input than that obtained in theconventional DT surface Aerator under the same operation conditions.
基金Supported by the National Technology Research and Development Program of China(2008AA062402)the China-US International Cooperation Project(2011DFA90800)the Ministry of Science and Technology,China
文摘CO2 removal from biogas by water washing system was investigated with various parameters, including liquid/ gas ratio, pressure, temperature, and CO2 content. The results indicate that CO2 removal ratio could reach 34.6%- 94.2% as liquid/gas ratio increased from 0.14 to 0.50. Increasing pressure （from 0.8 to 1.2 MPa） could improve gas purification with a constant inflow rate of gas. Temperature played a key role in the process and lower temper- ature in absorption tower was beneficial for reducing CO2 content. CO2 removal ratio could reach 24.4%-83.2% when CO2 content in the simulated gas was 25%-45%. The lowest CO2 content after absorption was 2.6% at 1.2 MPa with 400 L·h-1 gas flow and 200 L·h-1 water flow, which meets the requirement of CO2 content in natural Ras for vehicle fuel.
基金Supported by the National High Technology Research and Development Program of China(2008AA062401)the China-US International Cooperation Project(2011DFA90800)the Ministry of Science and Technology,China
文摘Aqueous ammonia was used to pretreat wheat straw to improve biodegradability and provide nitrogen source for enhancing biogas production. Three doses of ammonia(2%, 4%, and 6%, dry matter) and three moisture contents(30%, 60%, and 80%, dry matter) were applied to pretreat wheat straw for 7 days. The pretreated wheat straws were anaerobically digested at three loading rates(50, 65, and 80 g·L-1) to produce biogas. The results indicated that the wheat straw pretreated with 80% moisture content and 4% ammonia achieved the highest methane yield of 199.7 ml·g-1(based on per unit volatile solids loaded), with shorter digestion time(T80) of 25 days at the loading rate of 65 g·L-1compared to untreated one. The main chemical compositions of wheat straw were also analyzed. The cellulose and hemicellulose contents were decomposed by 2%-20% and 26%-42%, respectively,while the lignin content was hardly removed, cold-water and hot-water extracts were increased by 4%-44%, and12%-52%, respectively, for the ammonia-pretreated wheat straws at different moisture contents. The appropriate C/N ratio and decomposition of original chemical compositions into relatively readily biodegradable substances will improve the biodegradability and biogas yield.
文摘This study was considered to assess the risk of alum which is used in Sudan for drinking water treatment purposes for a long period without toxicity freedom records .Newzealand rabbits were chosen for animal phase trials, divided into 3 groups. One group was the undosed controls. Test groups were given alum at dose rates of 1% and 20% respectively for two groups after an adaptation period. Clinical signs were observed together with postmortem and histopathological examinations. Chemical investigations included enzymatic, metabolic, electrolyte and hematological changes. The test rabbits demonstrated low voice, inappitence, whitish salivation, watery diarrhea and recumbence followed by emphysematous, lungs, electrolyte imbalance, renal dysfunctions, stiff focal inflammation of the empty intestines and congested liver with white spots. The control group was normal .On atomic absorption only the lungs kept residual alum, while the livers washed- out the substance ,may be via bile .Alum -dosed rabbits showed necrosis in the cortex and medulla of the kidney, emphysema in the lungs and necrosis in the hepatocytes. On evaluation of the above results, alum was considered to be toxic to Newzealand rabbits at dose rates tried.
文摘The purpose of this work was to study the potential to enhance biogas production from pulp and paper mill sludge by the use of thermal pre-treatment in combination with chemical pre-treatment. Biogas from waste is a renewable fuel with very low emissions during combustion. To further reduce the use of fossil fuels, more biogas substrates are necessary. Pulp and paper mill sludge is a large untapped reservoir of potential biogas. Pulp and paper mill sludge was collected from a mill that produces both pulp and paper and has a modified waste activated sludge system as part of its wastewater treatment. Pre-treatments were chosen heat （70 ~C or 140℃） combined with either acid （pH 2 or pH 4） or base （pH 9 or pH 11, obtained with Ca（OH）2 or NaOH）. Biogas potential was tested by anaerobic digestion batch assays under mesophilic conditions. All pre-treatments were tested in six replicates. Biogas volume was measured with a gas-tight syringe and methane concentration was measured with a gas chromatograph. The methane yield from sludge subjected to thermal pre-treatment at 70℃ did not differ from the untreated sludge, but thermal pre-treatment at 140℃ had a positive effect. Within the 70℃ thermal pre-treatment group, the pH 2 acid was the most successful chemical pre-treatment, and Ca（OH）2 pH 9 had the least effect with no measurable improvement in methane yield. For the 140 ℃ thermal pre-treatment group, acid and NaOH impacted methane production negatively, while the Ca（OH）2-treated sludge did not differ from sludge with no chemical pre-treatment. In conclusion, thermal pre-treatment at 70℃ showed no effect, whereas, pre-treatment at 140℃ improved methane yield with 170%, and for this sludge additional, chemical pre-treatments are unnecessary.
基金supported by the GEF/UNDP Second National Communication on Climate Change of China--China’s inventory of GHG emissions from wastewater/sewage treatment subproject
文摘Based on the statistics from the China Statistical Yearbook （2000-2009） on environment and methods recommended by the IPCC, the amounts of greenhouse gas （GHG） emissions from domestic and industrial sewage treatment in China are estimated for the period of 2003-2009. CO2 emissions per capita from sewage treatment plants are also analyzed. The results show that the GHG emissions from sewage treatment plants increased steadily from 2003 to 2009; N20 emissions from domestic sewage are the major source of the total GHG emissions from domestic sewage; CH4 emissions from domestic sewage increase with the greatest speed; CH4 emissions from paper and pulp industry are the major source of industrial sewage emissions; CO2 emissions per capita increase constantly from 2003 to 2009.
文摘The increase of waste production, joined to the difficulties concerning both the identification of new disposal sites and the construction of big conventional incinerators, led in recent years to the development of new technologies for waste management such as gasification and melting treatments. The possibility to introduce in the Italian context the DMS （direct melting system） technology, designed and manufactured by Nippon Steel Engineering Co. Ltd., has been taken into account for the scope of proposed work. DMS technology consists in MSW gasification, slags melting and combustion of the syngas produced, with the consequent generation of electric energy through a steam cycle. The system minimizes environmental impact, thanks to an effective recycling of useful resources such as inert melted slags and metals, featuring high flexibility in terms of treatment capacity due to its modular design. The aim of this article is to consider different plant configurations in order to optimize the energy recovery downstream the DMS module. As a case study, landfill gas exploitation integrated in the DMS plant will be considered as a typical situation that could occur in the Italian scenario. The energetic input provided by the biogas allows improving the thermo-economic performances according to market incentives.
文摘Nowadays, people pass 90% of their time in closed spaces, therefore, an increasing care in the creation and upkeep of healthier environments as a personal and as professional level become a major issue. The present project has as goal the verification and optimization of the implicit need of an OCRAMclima~ AHU （air handling units） in IAQ （indoor air quality） and its effectiveness in treatment and/or air purification, having as basis the legal national and European requirements for IAQ. This work was based on the study of the state of the art of the techniques in air purification and in the evaluation of their performance, culminating in the production of the prototype OCRAMclima~ NPS （nano purifying system）. The purifying phenomena involved are UVGI （ultraviolet germicidal irradiation） and catalytic ionization of air. The performance test was accomplished in a closed loop circuit, which results, obtained by an independent IAQ analyst, were satisfactory, indicating the viability of application of this system to indoor air disinfection. The outcome revealed that the conjugating of both phenomena, the air sterilizing by UV and catalytic ionization, is efficient when used for air purification, mainly for volatile organic compounds and bioaerosols.
