Characterisation of enhanced biological phosphorus removal activated sludges with dissimilar phosphorus removal performances

Abstract

A sequencing batch reactor (SBR) was operated for enhanced biological phosphorus removal (EBPR) and dramatic differences in the P removing capabilities were obtained in different stages of the operation. At one stage extremely poor P removal occurred and it appeared that bacteria inhibiting P removal overwhelmed the reactor performance. Changes were made to the reactor operation and these led to the development of a sludge with high P removing capability. This latter sludge was analysed by fluorescent in situ hybridisation (FISH) using a probe specific for Acinetobacter. Very few cells were detected with this probe indicating that Acinetobacter played an insignificant role in the P removal occurring here. Analysis of the chemical transformations of three sludges supported the biochemical pathways proposed for EBPR and non-EBPR systems in biological models. A change in operation that led to the improved P removal performance included permitting the pH to rise in the anaerobic periods of the SBR cycle.

Enhanced Biological Phosphorus Removal from Wastewater by Biomass with Different Phosphorus Contents, Part I: Experimental Results and Comparison with Metabolic Models

“…Glycogen-accumulating metabolic activity is only undesirable when it leads to increased effluent P sol concentrations. This occurs when GAM is active for reasons other than phosphorus-limitation of PAM (e.g., due to low pH) (Bond et al, 1998;Filipe et al, 2001b;Jeon et al, 2001;Liu et al, 1996;Schuler and Jenkins, 2002) or the presence of glucose (Cech and Hartman, 1993). Measuring relative PAM and GAM activities by the proposed assays may be useful in determining the cause of process upsets.…”

“…Both PAM and GAM can be active in EBPR systems. Bond et al (1998) obtained three sludges from a laboratory-scale system that exhibited performance that was intermediate between that predicted by metabolic models for PAM (Smolders et al, 1994) and GAM (Satoh et al, 1994). Liu et al (1997) operated a laboratory-scale system over a range of influent phosphorus/acetate chemical oxygen demand (COD) ratios and produced biomass with a range of PAM and GAM activities.…”

Enhanced Biological Phosphorus Removal from Wastewater by Biomass with Different Phosphorus Contents, Part II: Anaerobic Adenosine Triphosphate Utilization and Acetate Uptake Rates

“…Glycogen-accumulating metabolism is, therefore, unlikely to successfully compete with PAM when acetate is the primary carbon source under the conditions studied (e.g., pH ¼ 7.15 to 7.25) unless PAM activity is limited by low influent phosphorus/acetate COD ratios. Other factors that favor GAM, such as the presence of glucose (Cech and Hartman, 1993) or low pH (Bond et al, 1998;Filipe et al, 2001b;Jeon et al, 2001;Liu et al, 1996;Schuler and Jenkins, 2002), may be necessary for GAM to compete successfully by means other than phosphorus limitation of PAM.…”

Elucidation of metabolic pathways in glycogen‐accumulating organisms with in vivo13C nuclear magnetic resonance

“…Poor performance or complete failure of EBPR processes has been often reported under seemingly favourable conditions for EBPR (Cech and Hartman, 1990; Cech and Hartman, 1993; Liu et al ., 1994; Satoh et al ., 1994; Tsai and Liu, 2002). In most of these cases, another group of bacteria, currently known as the glycogen‐accumulating organisms (GAOs), are able to proliferate in EBPR systems, competing with PAOs for the usually limiting carbon substrates (Satoh et al ., 1994; Bond et al ., 1998; Whang and Park, 2002).…”