Phosphorus removal performance in an aerobic/aerobic sequencing batch reactor (SBR) supplied with glucose as carbon source was investigated. It was found that there was no phosphate release concomitant with the storin...Phosphorus removal performance in an aerobic/aerobic sequencing batch reactor (SBR) supplied with glucose as carbon source was investigated. It was found that there was no phosphate release concomitant with the storing of poly-β-hydroxyalkanoate (PHA) during the anaerobic phase. Whereas, glycogen was soon built up followed by rapid consumption, at the same time, glucose was depleted rapidly. Based on the analysis of different fractions of phosphorus in activated sludge, the relative ratio of organically bound phosphorus in sludge changed at the end of anaerobic and aerobic phases. The ratios were 45.3% and 51.8% respectively. This showed that the polyphosphate broke down during the anaerobic phase to supply part of energy for PHA synthesis. The reason why there was no phosphate release might be the biosorption effect of extracellular exopolymers (EPS). It was also proved by the analysis of EPS with scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS). The phosphorus weight percentage of EPS at the end of anaerobic phase was 9.22%.展开更多
Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This s...Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.展开更多
The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activ...The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activated carbon filter was analyzed in a pilot-scale test and an innovative technology to improve the turbidity removal in a biologically activated carbon (BAC) filter was put forward in order to meet the criterion. Experimental results showed that the enhanced filtration by adding polymerized aluminium chloride (PAC) into the BAC filter was quite effective in turbidity control. The effluent turbidity was kept at a stable level (mean) of 0.033 NTU with a high removal of about 80% for influent turbidity of 0.110-0.240 NTU with an addition of PAC at 0.05 mg L -1, meeting the requirement for filtrate turbidity equal to or less than 0.1NTUC totally. In addition, the larger the PAC dosage was, the lower the effluent turbidity was. However, further improvement of turbidity removal was not obvious for PAC dosages beyond 0.10 mg L -1, and an optimal PAC dosage in the range of 0.]05-0.10 mg L -1 was proposed.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
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
文摘Phosphorus removal performance in an aerobic/aerobic sequencing batch reactor (SBR) supplied with glucose as carbon source was investigated. It was found that there was no phosphate release concomitant with the storing of poly-β-hydroxyalkanoate (PHA) during the anaerobic phase. Whereas, glycogen was soon built up followed by rapid consumption, at the same time, glucose was depleted rapidly. Based on the analysis of different fractions of phosphorus in activated sludge, the relative ratio of organically bound phosphorus in sludge changed at the end of anaerobic and aerobic phases. The ratios were 45.3% and 51.8% respectively. This showed that the polyphosphate broke down during the anaerobic phase to supply part of energy for PHA synthesis. The reason why there was no phosphate release might be the biosorption effect of extracellular exopolymers (EPS). It was also proved by the analysis of EPS with scanning electron microscopy (SEM) combined with energy dispersive spectrometry (EDS). The phosphorus weight percentage of EPS at the end of anaerobic phase was 9.22%.
文摘Biological aerated filter （BAF） is an advanced oxidation process that can sustain high volumetric loads with high quality effluent. However, backwashing process needed for the system limits its applicability. This study is to investigate the possibility of removing carbon and nitrogen simultaneously in a biological aerated filter （BAF） with partially packed media without any backwashing process. The upper part of BAF up to 0.5 m depth is packed with plastic media （Kaldnes K1） with diameter and length of 10 mm and 7 mm respectively. This partially packed BAF creates a hybrid system of attached growth and suspended growth combined in a single reactor. Three C：N ratios, i.e. 15, 10 and 4, were compared during this study by varying the nitrogen loading while the carbon loading was kept constant at 1.0±0.54 kg COD/（m^3·d）. The organic loading rate （OLR） ratios were calculated based on carbon and TKN loading. The carbon removal percentage of 86.7±7.3%, 85.1±10.3%, and 91.0±5.6% and TKN removal percentage of 24.7±11.6%, 48.0±25.9% and 62.8±7.9% were achieved after steady-state for the C：N ratio of 15, 10, and 4 respectively. Suspended solid concentration in the effluent was found to be high throughout the treatment, but no clogging occurred during the 4 months of operation period even though backwashing was eliminated.
文摘The turbidity criterion for the product water of a WTP according to the State Project ‘863’ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activated carbon filter was analyzed in a pilot-scale test and an innovative technology to improve the turbidity removal in a biologically activated carbon (BAC) filter was put forward in order to meet the criterion. Experimental results showed that the enhanced filtration by adding polymerized aluminium chloride (PAC) into the BAC filter was quite effective in turbidity control. The effluent turbidity was kept at a stable level (mean) of 0.033 NTU with a high removal of about 80% for influent turbidity of 0.110-0.240 NTU with an addition of PAC at 0.05 mg L -1, meeting the requirement for filtrate turbidity equal to or less than 0.1NTUC totally. In addition, the larger the PAC dosage was, the lower the effluent turbidity was. However, further improvement of turbidity removal was not obvious for PAC dosages beyond 0.10 mg L -1, and an optimal PAC dosage in the range of 0.]05-0.10 mg L -1 was proposed.
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）.
