Polyhydroxyalkanoate form and polyphosphate regulation: keys to biological phosphorus and glycogen transformations?

Randall, Andrew A.; Chen, Y.; Liu, Y.-H.; McCue, Terrence

doi:10.2166/wst.2003.0609

Cited by 8 publications

(4 citation statements)

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“…Concentrations of readily biodegradable COD, such as short-chain fatty acids (SCFAs), in wastewater strongly affect the efficiency of biological nutrient (phosphorus and nitrogen) removal processes. SCFAs, such as acetic and propionic acids, have been demonstrated to be the most suitable substrates to support enhanced biological phosphorus removal (EBPR) ( − ). It has been reported that 6−9 mg of SCFAs is required for biological removal of 1 mg of phosphorus ( − ).…”

Section: Introductionmentioning

confidence: 99%

Improved Bioproduction of Short-Chain Fatty Acids (SCFAs) from Excess Sludge under Alkaline Conditions

Yuan

Chen

Zhang

et al. 2006

Environ. Sci. Technol.

512

262

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The production of short-chain fatty acids (SCFAs) from excess sludge was conducted in batch fermentation tests at different pH values ranging from 4.0 to 11.0. Experimental results of the impacts of different pHs on SCFAs production showed that during the first 8-day fermentation time the total SCFAs production at either pH 9.0 or pH 10.0 was much greater than that at acidic or neutral pH, and the maximal yield of 256.2 mg SCFAs-COD per gram of volatile suspended solids (VSS) was at pH 10.0, which was, respectively, over3 and 4times that at pH 5.0 and uncontrolled pH. Clearly, SCFAs production from excess sludge could be significantly improved and maintained stable by controlling the fermentation pH at 10.0. The composition of SCFAs and the percent distribution of individual SCFAs accounting for total SCFAs at pH 10.0 were analyzed. The SCFAs consisted of acetic, propionic, iso-butyric, n-butyric, iso-valeric, and n-valeric acids, and acetic acid was the most prevalent product with a fraction of 40-55%. Because the results of this study were differentfrom those of previous studies of SCFAs production, the mechanism of increased SCFAs production under alkaline conditions was investigated. Results showed that as soluble COD increased, more soluble protein was provided as the substrate for producing SCFAs. In addition, less or even no SCFAs were consumed by methanogens at alkaline pH, so the SCFAs production was therefore remarkably improved. Further investigation revealed thatthe formation of SCFA at pH 10.0 was dominated by biological effects rather than by chemical hydrolysis.

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Section: Introductionmentioning

confidence: 99%

Improved Bioproduction of Short-Chain Fatty Acids (SCFAs) from Excess Sludge under Alkaline Conditions

Yuan

Chen

Zhang

et al. 2006

Environ. Sci. Technol.

512

262

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“…between PAOs and GAOs have been carried out during the last 10 years. In virtually all cases it was confirmed that better bio-P performance was obtained with propionate, or a mix of propionate and acetate, than with acetate alone (Levantesi et al 2002;Randall & Liu 2002;Randall et al 2003;Chen et al 2004;Oehmen et al 2004;Pijuan et al 2004;Oehmen et al 2005b;Lu et al 2006;Oehmen et al 2006b). …”

Section: Resultsmentioning

confidence: 79%

The secret to achieving reliable biological phosphorus removal

Thomas

2008

Water Science and Technology

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The enhanced biological phosphorus removal (bio-P) activated sludge process has a reputation for variable performance. A significant factor contributing to variability in bio-P was found to be related to microbial population dynamics involving the competitive growth of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). It was found that the key factor in their competitive growth was the specific type of VFA in the influent to the bioreactor. The PAOs seem to have a competitive advantage to use propionate, whereas the GAOs have a competitive advantage to use acetate. Therefore, the secret to achieving reliable biological phosphorus removal was to ensure an adequate supply of propionate, or an alternative substrate such as molasses that can be readily fermented to propionate.When Noosa WWTP was commissioned in Nov 1997, and for several years afterwards, the bio-P performance was found to be variable. This paper outlines the findings of the research and optimisation program that was carried out, which identified the cause of the variability in bio-P and subsequently lead to implementation of an improved operating strategy. The recent long-term results demonstrate that reliable bio-P can be achieved in full-scale wastewater treatment plants without dosing metal salts. The effluent total phosphorus has been maintained below 0.5 mg/L since Jul 2001 and the 50 percentile result for the last 12 months was 0.2 mg/L.

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“…A possible reason was that SOP removal was determined by SOP release and uptake. Moreover, SOP release was connected with wastewater acetic and propionic acid content, and SOP uptake was associated with both PHA degradation and SOP release [35]. The data in Fig.…”

Section: Relationship Between Pha Transformation and Tn Removal Efficmentioning

confidence: 84%

Research on polyhydroxyalkanoates and glycogen transformations: Key aspects to biologic nitrogen and phosphorus removal in low dissolved oxygen systems

Chen

2010

Front. Environ. Sci. Eng. China

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In this paper, a study was conducted on the effect of polyhydroxyalkanoates (PHA) and glycogen transformations on biologic nitrogen and phosphorus removal in low dissolved oxygen (DO) systems. Two laboratory-scale sequencing batch reactors (SBR1 and SBR2) were operating with anaerobic/aerobic (low DO, 0.15-0.45 mg$L -1 ) configurations, which cultured a propionic to acetic acid ratio (molar carbon ratio) of 1.0 and 2.0, respectively. Fewer poly-3-hydroxybutyrate (PHB), total PHA, and glycogen transformations were observed with the increase of propionic/acetic acid, along with more poly-3-hydroxyvalerate (PHV) and poly-3-hydroxy-2-methyvalerate (PH2MV) shifts. The total nitrogen (TN) removal efficiency was 68% and 82% in SBR1 and SBR2, respectively. In the two SBRs, the soluble ortho-phosphate (SOP) removal efficiency was 94% and 99%, and the average sludge polyphosphate (poly-P) content (g$g-MLVSS -1 ) was 8.3% and 10.2%, respectively. Thus, the propionic to acetic acid ratio of the influent greatly influenced the PHA form and quantity, glycogen transformation, and poly-P contained in activated sludge and further determined TN and SOP removal efficiency. Moreover, significant correlations between the SOP removal rate and the (PHV + PH2MV)/PHA ratio were observed (R 2 > 0.99). Accordingly, PHA and glycogen transformations should be taken into account as key components for optimizing anaerobic/aerobic (low DO) biologic nitrogen and phosphorus removal systems.

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Polyhydroxyalkanoate form and polyphosphate regulation: keys to biological phosphorus and glycogen transformations?

Cited by 8 publications

References 0 publications

Improved Bioproduction of Short-Chain Fatty Acids (SCFAs) from Excess Sludge under Alkaline Conditions

Improved Bioproduction of Short-Chain Fatty Acids (SCFAs) from Excess Sludge under Alkaline Conditions

The secret to achieving reliable biological phosphorus removal

Research on polyhydroxyalkanoates and glycogen transformations: Key aspects to biologic nitrogen and phosphorus removal in low dissolved oxygen systems

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