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
The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in a...The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic- anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-13-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating or- ganisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fer- mentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49-5.99 g N/(kg MLVSS.h) (MLVSS is mixed liquor volatile suspended solids) and 6.63-6.81 g N/(kg MLVSS.h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.展开更多
By using packed soil-core incubation experiments, we have studied stimulating effects of addition of external carbon (C) (glu- cose, 6.4 g C m 2) on heterotrophic respiration and microbial biomass C of a mature br...By using packed soil-core incubation experiments, we have studied stimulating effects of addition of external carbon (C) (glu- cose, 6.4 g C m 2) on heterotrophic respiration and microbial biomass C of a mature broadleaf and Korean pine mixed forest (BKPF) and an adjacent white birch forest (WBF) soil under different wetting intensities (55% and 80% WFPS, water-filled pore space) and nitrogen (N) supply (NH4C1 and KNO3, 4.5 g N m-e) conditions. The results showed that for the control, the cumulative carbon dioxide (CO2) flux from WBF soil during the 15-day incubation ranged from 5.44 to 5.82 g CO2-C m-2, which was significantly larger than that from BKPF soil (2.86 to 3.36 g CO2-C m 2). With increasing wetting intensity, the cumulative CO2 flux from the control was decreased for the WBF soil, whereas an increase in the CO2 flux was observed in the BKPF soil (P 〈 0.05). The addition of NH4C1 or KNO3 alone significantly reduced the cumulative CO2 fluxes by 9.2%-21.6 % from the two soils, especially from WBF soil at low wetting intensity. The addition of glucose alone significantly increased soil heterotrophic respiration, microbial biomass C (MBC), and microbial metabolic quotient. The glucose-induced cumulative CO2 fluxes and soil MBC during the incubation ranged from 8.7 to 11.7 g CO2-C m-2 and from 7.4 to 23.9 g C m-2, which are larger than the dose of added C. Hence, the addition of external carbon can increase the decomposition of soil native organic C. The glucose-induced average and maximum rates of CO2 fluxes during the incubation were significantly in- fluenced by wetting intensity (WI) and vegetation type (VT), and by WIxVT, NH4ClxVT and WIxVTxNH4C1 (P〈0.05). The addition of NH4C1, instead of KNO3, significantly decreased the glucose-induced MBC of WBF soil (P〈0.05), whereas adding NH4C1 and KNO3 both significantly increased the glucose-induced MBC of BKPF soil at high moisture (P〈0.05). According to the differences in soil labile C pools, MBC and CO2 fluxes in the presence and absence of glucose, it can be concluded that the stimulating effects of glucose on soil heterotrophic respiration and MBC under temperate forests were dependent on vegetation type, soil moisture, and amount and type of the N added.展开更多
The effects of two different external carbon sources (acetate and ethanol) and electron acceptors (dissolved oxygen, nitrate, and nitrite) were investigated under aerobic and anoxic conditions with non-acclimated ...The effects of two different external carbon sources (acetate and ethanol) and electron acceptors (dissolved oxygen, nitrate, and nitrite) were investigated under aerobic and anoxic conditions with non-acclimated process bi- omass from a full-scale biological nutrient removal-activated sludge system. When acetate was added as an external carbon source, phosphate release was observed even in the presence of electron acceptors. The release rates were 1.7, 7.8, and 3.5 mg P/(g MLVSS.h) (MLVSS: mixed liquor volatile suspended solids), respectively, for dissolved oxygen, nitrate, and nitrite. In the case of ethanol, no phosphate release was observed in the presence of electron acceptors. Results of the experiments with nitrite showed that approximately 25 mg NO2-N/L of nitrite inhibited anoxic phosphorus uptake regardless of the concentration of the tested external carbon sources. Furthermore, higher deni- trification rates were obtained with acetate (1.4 and 0.8 mg N/(g MLVSS.h)) compared to ethanol (1.1 and 0.7 mg N/ (g MLVSS.h)) for both anoxic electron acceptors (nitrate and nitrite).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 National Water Pollution Control and Management of Major Special Science and Technology Foundation(No.2011ZX07303-001),China
文摘The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic- anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-13-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating or- ganisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fer- mentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49-5.99 g N/(kg MLVSS.h) (MLVSS is mixed liquor volatile suspended solids) and 6.63-6.81 g N/(kg MLVSS.h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.
基金financially supported jointly by the National Basic Research Program of China(Grant No.2010CB950602)the National Natural Science Foundation of China(Grant Nos.41175133,21228701,41275166,and 41321064)
文摘By using packed soil-core incubation experiments, we have studied stimulating effects of addition of external carbon (C) (glu- cose, 6.4 g C m 2) on heterotrophic respiration and microbial biomass C of a mature broadleaf and Korean pine mixed forest (BKPF) and an adjacent white birch forest (WBF) soil under different wetting intensities (55% and 80% WFPS, water-filled pore space) and nitrogen (N) supply (NH4C1 and KNO3, 4.5 g N m-e) conditions. The results showed that for the control, the cumulative carbon dioxide (CO2) flux from WBF soil during the 15-day incubation ranged from 5.44 to 5.82 g CO2-C m-2, which was significantly larger than that from BKPF soil (2.86 to 3.36 g CO2-C m 2). With increasing wetting intensity, the cumulative CO2 flux from the control was decreased for the WBF soil, whereas an increase in the CO2 flux was observed in the BKPF soil (P 〈 0.05). The addition of NH4C1 or KNO3 alone significantly reduced the cumulative CO2 fluxes by 9.2%-21.6 % from the two soils, especially from WBF soil at low wetting intensity. The addition of glucose alone significantly increased soil heterotrophic respiration, microbial biomass C (MBC), and microbial metabolic quotient. The glucose-induced cumulative CO2 fluxes and soil MBC during the incubation ranged from 8.7 to 11.7 g CO2-C m-2 and from 7.4 to 23.9 g C m-2, which are larger than the dose of added C. Hence, the addition of external carbon can increase the decomposition of soil native organic C. The glucose-induced average and maximum rates of CO2 fluxes during the incubation were significantly in- fluenced by wetting intensity (WI) and vegetation type (VT), and by WIxVT, NH4ClxVT and WIxVTxNH4C1 (P〈0.05). The addition of NH4C1, instead of KNO3, significantly decreased the glucose-induced MBC of WBF soil (P〈0.05), whereas adding NH4C1 and KNO3 both significantly increased the glucose-induced MBC of BKPF soil at high moisture (P〈0.05). According to the differences in soil labile C pools, MBC and CO2 fluxes in the presence and absence of glucose, it can be concluded that the stimulating effects of glucose on soil heterotrophic respiration and MBC under temperate forests were dependent on vegetation type, soil moisture, and amount and type of the N added.
基金Project supported by the European Regional Development Fund within the Framework of the Innovative Economy Operational Program 2007-2013(No.UDA-POIG.01.03.01-22-140/09-04)the CARbon BALAncing for Nutrient Control in Wastewater Treatment(CARBALA)(No.PIRSES-GA-2011-295176)the National Water Pollution Control and Management of Science and Technology in China(No.2015ZX07218001)
文摘The effects of two different external carbon sources (acetate and ethanol) and electron acceptors (dissolved oxygen, nitrate, and nitrite) were investigated under aerobic and anoxic conditions with non-acclimated process bi- omass from a full-scale biological nutrient removal-activated sludge system. When acetate was added as an external carbon source, phosphate release was observed even in the presence of electron acceptors. The release rates were 1.7, 7.8, and 3.5 mg P/(g MLVSS.h) (MLVSS: mixed liquor volatile suspended solids), respectively, for dissolved oxygen, nitrate, and nitrite. In the case of ethanol, no phosphate release was observed in the presence of electron acceptors. Results of the experiments with nitrite showed that approximately 25 mg NO2-N/L of nitrite inhibited anoxic phosphorus uptake regardless of the concentration of the tested external carbon sources. Furthermore, higher deni- trification rates were obtained with acetate (1.4 and 0.8 mg N/(g MLVSS.h)) compared to ethanol (1.1 and 0.7 mg N/ (g MLVSS.h)) for both anoxic electron acceptors (nitrate and nitrite).