Anoxic Phosphate Uptake in the DEPHANOX Process

Bortone, G.; Libelli, Stefano Marsili; Tilche, A.; Wanner, J.

doi:10.2166/wst.1999.0590

Cited by 31 publications

(16 citation statements)

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“…This latter P release is probably due to leakage of some RBCOD out of the anaerobic reactor, stimulating P release in the sludge blanket formed in the bottom of the internal settling tank. This was not unexpected as similar observations had been made in previous investigations into the DEPHANOX system (Bortone et al, 1997). This additional P release is beneficial because it augments the anaerobic P release.…”

Section: P Release and Uptakesupporting

confidence: 89%

Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system

Sötemann

Moodley

et al. 2003

Biotech & Bioengineering

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A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to <30% and concommitantly the anoxic mass fraction can be increased from 25% to 35% to >55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand.

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Section: P Release and Uptakesupporting

confidence: 89%

Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system

Sötemann

Moodley

et al. 2003

Biotech & Bioengineering

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“…Unlike previously proposed processes that applied DNPAOs in SBRs for nitrogen and phosphorus removal in a single reactor (Lee et al, 2001;Tsuneda et al, 2006;Zeng et al, 2003bZeng et al, , 2004, the SBMBfR does not seem to require strict control of oxygen supply or TOC addition, because the nitrifying bacteria immobilized onto the fibrous support have priority access to the oxygen supplied through the gas-permeable membrane. This characteristic induces DNPAO activity in the bulk liquid; in other words, the SBMBfR generates ''two-sludge system''-like conditions in a single reactor (Bortone et al, 1999;Shoji et al, 2003). In this study, the membrane fibrous support was employed for the maintenance of the biofilm in the direction of its thickness.…”

Section: Discussion System Validitymentioning

confidence: 99%

Sequencing batch membrane biofilm reactor for simultaneous nitrogen and phosphorus removal: Novel application of membrane‐aerated biofilm

Terada

Yamamoto

Tsuneda

et al. 2006

Biotech & Bioengineering

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A sequencing batch membrane biofilm reactor (SBMBfR) was developed for simultaneous carbon, nitrogen, and phosphorus removal from wastewater. This reactor was composed of two functional parts: (1) a gas-permeable membrane on which a nitrifying biofilm formed and (2) a bulk solution in which bacteria, mainly denitrifying polyphosphate-accumulating organisms (DNPAOs), were suspended. The reactor was operated sequentially under anaerobic condition and then under membrane aeration condition in one cycle. During the anaerobic period, organic carbon was consumed by DNPAOs; this was accompanied by phosphate release. During the subsequent membrane aeration period, nitrifying bacteria utilized oxygen supplied directly to them from the inside of the membrane. Consequently, the nitrite and nitrate products diffused into the bulk solution, where they were used by DNPAOs as electron acceptors for phosphate uptake. In a long-term sequencing batch operation, the mean removal efficiencies of total organic carbon (TOC), total nitrogen (T-N), and total phosphorus (T-P) under steady-state condition were 99%, 96%, and 90%, respectively. In addition, fluorescence in situ hybridization (FISH) clearly demonstrated the difference in bacterial community structure between the membrane biofilm and the suspended sludge: ammonia-oxidizing bacteria belonging to the Nitrosomonas group were dominant in the region adjacent to the membrane throughout the operation, and the occupation ratio of the well-known polyphosphate-accumulating organism (PAO) Candidatus "Accumulibacter phosphates" in the suspended sludge gradually increased to a maximum of 37%.

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“…DPAOs have the same anaerobic metabolism as non-DPAOs and their anoxic metabolism is similar to non-DPAO aerobic metabolism, with the main difference being the final electron acceptor. The presence of DPAOs in the system allows for the simultaneous removal of N and P, which benefits the process in terms of COD (lower COD demand), energy (less aeration) and sludge production (lower) [4][5][6]. However, there is no consensus as to whether DPAOs and non-DPAOs are different microorganisms [5,[7][8][9] or if they are the same microorganism, in which different levels of denitrifying enzymes were induced [6,10,11].…”

Section: Introductionmentioning

confidence: 99%

Microbial population response to changes of the operating conditions in a dynamic nutrient-removal sequencing batch reactor

Freitas

Temudo

Reis

2005

Bioprocess Biosyst Eng

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A nutrient-removal sequencing batch reactor operated with short anaerobic/aerobic cycles was subjected to different operating conditions, namely, cycle length, feeding pattern and feed composition. The changes in microbial population, as well as the contribution of microbial groups to the total nutrient removal, were estimated using the kinetic parameters obtained in this study. Denitrifying polyphosphate-accumulating organisms (DPAOs) were detected in the system, representing a fraction of 23% of phosphorus-accumulating organisms (PAOs). The results suggest that DPAOs and non-DPAOs are different microorganisms. The presence of nitrate in the feed stimulated DPAOs to predominate over non-DPAOs. Feeding the reactor with a mixture of organic substrates also stimulated DPAOs. Glycogen-accumulating organisms (GAOs) were likely to be present in the system and their development over PAOs was apparently favoured by increasing the aeration time and feeding during the aerobic phase. In contrast, the presence of propanoate in the feed apparently favoured PAOs over GAOs.

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Anoxic Phosphate Uptake in the DEPHANOX Process

Cited by 31 publications

References 0 publications

Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system

Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system

Sequencing batch membrane biofilm reactor for simultaneous nitrogen and phosphorus removal: Novel application of membrane‐aerated biofilm

Microbial population response to changes of the operating conditions in a dynamic nutrient-removal sequencing batch reactor

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