[Objective] The study was conducted to optimize the operation parameters of water control equipment for deep-litter beddings. [Method] A four-factor three-level orthogonal design was adopted to optimize experimental t...[Objective] The study was conducted to optimize the operation parameters of water control equipment for deep-litter beddings. [Method] A four-factor three-level orthogonal design was adopted to optimize experimental temperature, stopping time of aeration, aeration time and aeration rate by 9 groups of experiments, so as to improve the water removal efficiency of adopted mixed and reduce operation energy consumption. [Result] The average water contents in the mixed bedding under 3 temperatures decreased by 4.58% ±2.91%, 13.17% ±3.77% and 10.8% ±7.72%, respectively; the highest water removal efficiency could be achieved under an experimental temperature at 45 ℃, stopping time of aeration of 15 min, aeration time of 7 min, and an aeration rate at 4 m^3/min, which formed the optimal factor combination mode of the operation parameter of the water control equipment; the effects of various experimental factors on water content in the bedding were in order of aeration ratetemperatureaeration timestopping time of aeration; and the effects of various experimental factors on water removal efficiency in the bedding were in order of temperatureaeration rateaeration timestopping time of aeration. [Conclusion] After the optimization of operation parameters of the water control equipment for the deep-litter bedding, water removal efficiency of the mixed bedding could be improved, and the operation energy consumption of the equipment could be reduced.展开更多
This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determ...This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determine the effect of salinity on the contaminants＇ removal performance. The effect of hydraulic retention time （HRT） variation on treatment efficiency of the reed wetland was also discussed. Average removal efficiencies of the reed （Phragmites australis） wetland were found to be 79.0% for COD, 72.2% for ammonia nitrogen （NH3-N） and 82.8% for total phosphorus （TP）. Reed planting had obvious improvement on COD and NH3-N removal efficiency when compared to an unplanted system. With the seawater proportion in the influent increasing from 20% to 30%, the TP removal efficiency improved obviously. COD removal efficiency of the reed wetland was positively correlated with HRT under high salinity condition, while excess HRT had adverse impacts on the NH3-N and TP removal. Optimal HRT for NH3-N and TP removal was 4 days. Results obtained can be beneficially used to improve the use of constructed wetlands in saline wastewater treatment.展开更多
Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254and A410 from humic acid solutions were examined. The...Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254and A410 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of ClO2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.展开更多
Particles behaviour was monitored and analyzed in a stormwater wetland over a period of 4 months (June-September,2009).The results indicated that the particles behaviour can be affected by many processes,such as sedim...Particles behaviour was monitored and analyzed in a stormwater wetland over a period of 4 months (June-September,2009).The results indicated that the particles behaviour can be affected by many processes,such as sedimentation,resuspension,adsorption and release in stormwater wetlands during dry days.Due to the effects of these factors,the particles removal efficiency calculated based on the settling theory was significantly higher than the value obtained using the measured particles number concentration.And the measured efficiency showed a turning point in the range of 2-4 μm,which was within the colloidal particles range.Analysis of particle size distribution showed that particles were finer in the outflow than inflow due to sedimentation of the coarse particles and resuspension of the fine particles in the wetland.Particles in different size ranges play different roles in their contribution to turbidity and total suspended solids concentration.The finer particles (less than 10μm) showed a closer relationship with the turbidity while coarser particles (>4μm) were more related to total suspended solid concentration.展开更多
Laboratory scale model of DMMBF （dual mixed media biofilter） were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR colum...Laboratory scale model of DMMBF （dual mixed media biofilter） were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR column--2.2 m height and 300 mm diameter. The first mixed media filter of depth 640mm mixed of sand, rice husk and granular activated carbon. The percentage volume mix is 1：1：1. While the other mixed media of depth 740 mm, consisting of coal, crash porcelinaite, rock and granite with equally percentage volume. Fifty samples were collected during the experiments, which was spread over a period of forty two weeks. The obtained results indicate that when the flow loading raised from 0.15 L/min to 2.7 L/rain, the removal efficiency of BOD decreased 8%-11%, and the removal efficiency of COD deceased 3%-4%, while the removal efficiency of turbidity increased with the decreasing of hydraulic loading. The results showed that the removal efficiency of turbidity is more than 95% at the lower discharge （0.15 L/min）. Therefore, infiltration should be conservatively designed using low loading rates.展开更多
A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the effi...A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the efficiency of combined operation conditions of anaerobic-aerobic and anaerobic-aerobic-flocculation as well as chemical phosphorus removal of hypersaline mustard wastewater are conducted. The optimal operation condition and parameters in pretreatment of mustard wastewater in winter （the water temperature ranges 8-15 ~C） are determined： the anaerobic load is 3.0 kg （COD）/（m3.d）, the average COD and phosphate concentration of the inflow are respectively 3 883 mg/L and 35.53 mg/L and the dosage of flocculent （PAC） is 400 mg/L. The anaerobic-aerobic-flocculation combined operation condition and postpositive phosphorous removal with ferrous sulfate are employed. After treatment, the COD of the effluent is 470 mg/L and the average phosphate concentration is 5.09 mg/L. The effluent could achieve the third-level of Integrated Wastewater Discharge Standard （GB 8978--1996）.展开更多
The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. S...The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.展开更多
In this bench scale submerged membrane bioreactor, effect of solid retention time and hydraulic retention time on membrane fouling propensity has been studied. This experiment is carried out at different solid retenti...In this bench scale submerged membrane bioreactor, effect of solid retention time and hydraulic retention time on membrane fouling propensity has been studied. This experiment is carried out at different solid retention time of 5, 10, 30, 70 and 98 days; and fouling behavior of membrane bioreactor is investigated. Average effluent quality is found to be 88.14%-94.38%. The experiment with different hydraulic retention is carried for 3 to 4 days and fouling behavior has been investigated. The effluent quality at different hydraulic retention time of 1, 2, 3, 5, 10 and 24 hours has been investigated. This paper aims to search optimal values of solid and hydraulic retention times at which lower fouling and higher organic removal efficiency can be obtained. This study has been mainly focused on operating parameters rather than microbial structure, effect and analysis of activated sludge to membrane fouling.展开更多
In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the...In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the working principle, the craft character, as well as the problems existed in the practical application of the improved oxidation ditch, and raises some corresponding processing countermeasures. Looked from the running situation of Wu Long kou sewage treatment plant, the improved oxidation ditch have certain advantages in city sewage treatment, such as high organic removing efficiency, good removing effect of nitrogen and phosphorus, low investing expenses and operating cost and so on. It is a craft that is worth promoting in urban sewage treatment.展开更多
基金Supported by the Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(13)3073)Jiangsu Science and Technology Support Program(BE2014-342-1)~~
文摘[Objective] The study was conducted to optimize the operation parameters of water control equipment for deep-litter beddings. [Method] A four-factor three-level orthogonal design was adopted to optimize experimental temperature, stopping time of aeration, aeration time and aeration rate by 9 groups of experiments, so as to improve the water removal efficiency of adopted mixed and reduce operation energy consumption. [Result] The average water contents in the mixed bedding under 3 temperatures decreased by 4.58% ±2.91%, 13.17% ±3.77% and 10.8% ±7.72%, respectively; the highest water removal efficiency could be achieved under an experimental temperature at 45 ℃, stopping time of aeration of 15 min, aeration time of 7 min, and an aeration rate at 4 m^3/min, which formed the optimal factor combination mode of the operation parameter of the water control equipment; the effects of various experimental factors on water content in the bedding were in order of aeration ratetemperatureaeration timestopping time of aeration; and the effects of various experimental factors on water removal efficiency in the bedding were in order of temperatureaeration rateaeration timestopping time of aeration. [Conclusion] After the optimization of operation parameters of the water control equipment for the deep-litter bedding, water removal efficiency of the mixed bedding could be improved, and the operation energy consumption of the equipment could be reduced.
文摘This study evaluated the capability of a constructed wetland for treating saline wastewater. A pilot-scale constructed wetland system was set up and was initially operated at low, then increasing salt levels to determine the effect of salinity on the contaminants＇ removal performance. The effect of hydraulic retention time （HRT） variation on treatment efficiency of the reed wetland was also discussed. Average removal efficiencies of the reed （Phragmites australis） wetland were found to be 79.0% for COD, 72.2% for ammonia nitrogen （NH3-N） and 82.8% for total phosphorus （TP）. Reed planting had obvious improvement on COD and NH3-N removal efficiency when compared to an unplanted system. With the seawater proportion in the influent increasing from 20% to 30%, the TP removal efficiency improved obviously. COD removal efficiency of the reed wetland was positively correlated with HRT under high salinity condition, while excess HRT had adverse impacts on the NH3-N and TP removal. Optimal HRT for NH3-N and TP removal was 4 days. Results obtained can be beneficially used to improve the use of constructed wetlands in saline wastewater treatment.
基金Natural Science Foundation of China (No50478103)State Key Project for Small Towns Development of Ministry of Science and Technology of China (No2003BA808A17)
文摘Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254and A410 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of ClO2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.
基金supported by the National Natural Science Foundation of China (GrantNo.:51002196,and 51009156)the Fundamental Research Funds for the Central Universities (Grant No.11lgpy100)the Natural Science Foundation of Guangdong Province (Grant No.10451061101005309)
文摘Particles behaviour was monitored and analyzed in a stormwater wetland over a period of 4 months (June-September,2009).The results indicated that the particles behaviour can be affected by many processes,such as sedimentation,resuspension,adsorption and release in stormwater wetlands during dry days.Due to the effects of these factors,the particles removal efficiency calculated based on the settling theory was significantly higher than the value obtained using the measured particles number concentration.And the measured efficiency showed a turning point in the range of 2-4 μm,which was within the colloidal particles range.Analysis of particle size distribution showed that particles were finer in the outflow than inflow due to sedimentation of the coarse particles and resuspension of the fine particles in the wetland.Particles in different size ranges play different roles in their contribution to turbidity and total suspended solids concentration.The finer particles (less than 10μm) showed a closer relationship with the turbidity while coarser particles (>4μm) were more related to total suspended solid concentration.
文摘Laboratory scale model of DMMBF （dual mixed media biofilter） were designed and installed in AI-Mustansiriya University Environmental Hydraulic Lab. Experiments were conducted using two mixed layers through PVR column--2.2 m height and 300 mm diameter. The first mixed media filter of depth 640mm mixed of sand, rice husk and granular activated carbon. The percentage volume mix is 1：1：1. While the other mixed media of depth 740 mm, consisting of coal, crash porcelinaite, rock and granite with equally percentage volume. Fifty samples were collected during the experiments, which was spread over a period of forty two weeks. The obtained results indicate that when the flow loading raised from 0.15 L/min to 2.7 L/rain, the removal efficiency of BOD decreased 8%-11%, and the removal efficiency of COD deceased 3%-4%, while the removal efficiency of turbidity increased with the decreasing of hydraulic loading. The results showed that the removal efficiency of turbidity is more than 95% at the lower discharge （0.15 L/min）. Therefore, infiltration should be conservatively designed using low loading rates.
基金Project(20090191120036) supported by the Fund of Doctoral Program of Ministry of Education,China
文摘A full-scale experimental study of treating mustard wastewater by the integrated bioreactor with designed scale of 1 000 m3/d is conducted combined with a demonstration project. The systematical researches on the efficiency of combined operation conditions of anaerobic-aerobic and anaerobic-aerobic-flocculation as well as chemical phosphorus removal of hypersaline mustard wastewater are conducted. The optimal operation condition and parameters in pretreatment of mustard wastewater in winter （the water temperature ranges 8-15 ~C） are determined： the anaerobic load is 3.0 kg （COD）/（m3.d）, the average COD and phosphate concentration of the inflow are respectively 3 883 mg/L and 35.53 mg/L and the dosage of flocculent （PAC） is 400 mg/L. The anaerobic-aerobic-flocculation combined operation condition and postpositive phosphorous removal with ferrous sulfate are employed. After treatment, the COD of the effluent is 470 mg/L and the average phosphate concentration is 5.09 mg/L. The effluent could achieve the third-level of Integrated Wastewater Discharge Standard （GB 8978--1996）.
基金Project(2012AA06A202)supported by Hi-tech Research and Development Project of China
文摘The removal efficiencies of heavy metals(As, Cr, Cu, Ni, Pb and Zn) were investigated in the 17 operating municipal wastewater treatment plants(WWTPs) and compared with those in four main activated sludge processes. Significant differences of heavy metal removal efficiencies were observed among four activated sludge processes. The removal efficiency for As(75.5%) in the oxidation ditch(OD) process is significantly higher than that in the conventional activated sludge(CAS) process(38.6%) or sequencing batch reactor(SBR) process(51.4%). The mean removal efficiencies for Cu and Ni in the OD process are 90.5% and 46.7%, respectively, while low mean removal efficiencies are observed for Cu(69.9%) and Ni(16.5%), respectively, in the SBR process. The removal efficiencies for Cu and Ni in the OD process are significantly higher than those in the anaerobic-anoxic-oxic(A2-O) process. These results highlight the differences of removal efficiencies for heavy metals in different processes and should be considered when selecting a wastewater treatment process.
文摘In this bench scale submerged membrane bioreactor, effect of solid retention time and hydraulic retention time on membrane fouling propensity has been studied. This experiment is carried out at different solid retention time of 5, 10, 30, 70 and 98 days; and fouling behavior of membrane bioreactor is investigated. Average effluent quality is found to be 88.14%-94.38%. The experiment with different hydraulic retention is carried for 3 to 4 days and fouling behavior has been investigated. The effluent quality at different hydraulic retention time of 1, 2, 3, 5, 10 and 24 hours has been investigated. This paper aims to search optimal values of solid and hydraulic retention times at which lower fouling and higher organic removal efficiency can be obtained. This study has been mainly focused on operating parameters rather than microbial structure, effect and analysis of activated sludge to membrane fouling.
文摘In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the working principle, the craft character, as well as the problems existed in the practical application of the improved oxidation ditch, and raises some corresponding processing countermeasures. Looked from the running situation of Wu Long kou sewage treatment plant, the improved oxidation ditch have certain advantages in city sewage treatment, such as high organic removing efficiency, good removing effect of nitrogen and phosphorus, low investing expenses and operating cost and so on. It is a craft that is worth promoting in urban sewage treatment.
