Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, a...Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic(A2 /O). The ASM2 d implemented on the platform of WEST2011 software and the Bio Win activated sludge/anaerobic digestion(AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2 d parameters(the reduction factor for denitrification(η NO3, H), the maximum growth rate of heterotrophs( μ H), the rate constant for stored polyphosphates in PAOs(q pp), and the hydrolysis rate constant(k h)) were adjusted. Whereas three Bio Win parameters(aerobic decay rate(b H), heterotrophic dissolved oxygen(DO) half saturation(K OA), and Y P /acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations(ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen(N-NO3), total nitrogen(TN), and total phosphorus(TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand(COD) to total Kjeldahl nitrogen(TKN) ratio(COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.展开更多
We recorded NO3-N, NOz-N, NH4-N, PO4-P, SiO3-Si, salinity, and temperature data at 10 stations in the Dongshan Bay in May, June, July, August, October, and November 2008, analyzing nutrient and eutrophication characte...We recorded NO3-N, NOz-N, NH4-N, PO4-P, SiO3-Si, salinity, and temperature data at 10 stations in the Dongshan Bay in May, June, July, August, October, and November 2008, analyzing nutrient and eutrophication characteristics. The mean concentration of dissolved inorganic nitrogen （DIN） was 0.304）.40 mg/dm3; generally, NO3-N was the main form in most areas. The mean concentrations of PO4-P and SiO3-Si were 0.0404）.060 mg/dm3 and 1.00-1.50 mg/dm3, respectively. We proved that the majority of the SiO3-Si in the Dongshan Bay came from the Zhangjiang River, with some coming from the Bachimen Strait. DIN originated from both the Zhangjiang River and the Bachimen Strait. Most PO4-P originated from the Bachimen Strait, and some came from the Zhangjiang River. We found that P was an overall limiting factor to the phytoplankton community in most of the Dongshan Bay, and that Si and N were in surplus. However, near the Bachimen Strait Si became a limiting factor, especially for diatoms, while P and N were in comparative surplus. We used a potential eutrophication assessment method to analyze eutrophication, and showed that the most serious eutrophication occurred near the Zhangjiang River estuary and near the Bachimen Strait. In 2008, DIN levels were four times higher than that in 1988; PO4-P levels were three- fold higher, while SiO3-Si was approximately double. Dissolved nutrients increased between 1988 and 2008. DIN increased at the greatest rate comparing to PO4-P and SiO3-Si, thus the N/P and N/Si mol ratios increased. Further studies on the effects of high DIN concentrations on the phytoplankton communities and marine ecosystems of the Dongshan Bay are needed.展开更多
The levels of nitrates and nitrites in drinking water from two local government areas in Ilorin, Kwara State were determined using HACH DR/EL 5 Spectrnphotometer over a period of four months. The average mean concentr...The levels of nitrates and nitrites in drinking water from two local government areas in Ilorin, Kwara State were determined using HACH DR/EL 5 Spectrnphotometer over a period of four months. The average mean concentration of nitrate （NO3-N） in borehole is 0.185 mg/L and for nitrites （NO2-N） is 0.044 mg/L. The mean concentration in well for the nitrate （NOs-N） is 0.915 mg/L and for nitrites is 0.087 mg/L. The observed means as well as the highest single-point values for both nitrates and nitrites in groundwater are well below WHO （World Health Organisation） MCL （maximum contaminant level） of 10.0 mg/L nitrate as NO3-N and 3.0 mg/L nitrite as NO2-N. The values are also below the NSDWQ＇s （Nigerian Standard for Drinking Water Quality） maximum permitted level of 50 mg/L nitrate as NO3-N and 0.2 mg/L nitrite as NO2-N.展开更多
基金Supported by the College of Scientific Innovation Significant Cultivation Fund Financing Projects(No.708047)the Key Special Program for the Pollution Control(No.2012ZX07101-003)+1 种基金the National Natural Science Foundation of China(No.51208173)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic(A2 /O). The ASM2 d implemented on the platform of WEST2011 software and the Bio Win activated sludge/anaerobic digestion(AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2 d parameters(the reduction factor for denitrification(η NO3, H), the maximum growth rate of heterotrophs( μ H), the rate constant for stored polyphosphates in PAOs(q pp), and the hydrolysis rate constant(k h)) were adjusted. Whereas three Bio Win parameters(aerobic decay rate(b H), heterotrophic dissolved oxygen(DO) half saturation(K OA), and Y P /acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations(ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen(N-NO3), total nitrogen(TN), and total phosphorus(TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand(COD) to total Kjeldahl nitrogen(TKN) ratio(COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.
基金Supported by the Scientific Research Foundation of Third Institute of Oceanography,SOA(No.20140014)the Natural Science Foundation of Fujian Province(No.2012Y0048)the Monitoring,Predicting,Prevention and Mitigation of HABs Hazards(No.HD120201-12)
文摘We recorded NO3-N, NOz-N, NH4-N, PO4-P, SiO3-Si, salinity, and temperature data at 10 stations in the Dongshan Bay in May, June, July, August, October, and November 2008, analyzing nutrient and eutrophication characteristics. The mean concentration of dissolved inorganic nitrogen （DIN） was 0.304）.40 mg/dm3; generally, NO3-N was the main form in most areas. The mean concentrations of PO4-P and SiO3-Si were 0.0404）.060 mg/dm3 and 1.00-1.50 mg/dm3, respectively. We proved that the majority of the SiO3-Si in the Dongshan Bay came from the Zhangjiang River, with some coming from the Bachimen Strait. DIN originated from both the Zhangjiang River and the Bachimen Strait. Most PO4-P originated from the Bachimen Strait, and some came from the Zhangjiang River. We found that P was an overall limiting factor to the phytoplankton community in most of the Dongshan Bay, and that Si and N were in surplus. However, near the Bachimen Strait Si became a limiting factor, especially for diatoms, while P and N were in comparative surplus. We used a potential eutrophication assessment method to analyze eutrophication, and showed that the most serious eutrophication occurred near the Zhangjiang River estuary and near the Bachimen Strait. In 2008, DIN levels were four times higher than that in 1988; PO4-P levels were three- fold higher, while SiO3-Si was approximately double. Dissolved nutrients increased between 1988 and 2008. DIN increased at the greatest rate comparing to PO4-P and SiO3-Si, thus the N/P and N/Si mol ratios increased. Further studies on the effects of high DIN concentrations on the phytoplankton communities and marine ecosystems of the Dongshan Bay are needed.
文摘The levels of nitrates and nitrites in drinking water from two local government areas in Ilorin, Kwara State were determined using HACH DR/EL 5 Spectrnphotometer over a period of four months. The average mean concentration of nitrate （NO3-N） in borehole is 0.185 mg/L and for nitrites （NO2-N） is 0.044 mg/L. The mean concentration in well for the nitrate （NOs-N） is 0.915 mg/L and for nitrites is 0.087 mg/L. The observed means as well as the highest single-point values for both nitrates and nitrites in groundwater are well below WHO （World Health Organisation） MCL （maximum contaminant level） of 10.0 mg/L nitrate as NO3-N and 3.0 mg/L nitrite as NO2-N. The values are also below the NSDWQ＇s （Nigerian Standard for Drinking Water Quality） maximum permitted level of 50 mg/L nitrate as NO3-N and 0.2 mg/L nitrite as NO2-N.
