Effect of Variable Influent Loading on Biological Phosphorus Removal

Chiesa, Steven C.; Postiglione, James A.; Bjelland, Mark D.

doi:10.1061/(asce)0733-9372(1987)113:5(1058)

Cited by 4 publications

(1 citation statement)

References 15 publications

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“…This is necessary to obtain excess phosphate uptake in the aerobic zone [59]. The following cxplanations have been given for the reduction of the phosphate release by nitrate: (i) precipitation of phosphate duc to an increase in pH under denitrifying conditions [60,61]; (ii) inhibition of enzymes involved in the phosphate release [62,63]; (iii) increase in the redox potential by nitrate [64,65]; (iv) competition between denitrifying and polyP-accumulating bacteria for the same organic substrate [66][67][68][69][70]; and (v) the presence of denitrifying bacteria which also accumulate large quantities of phosphate [16,57,[71][72][73][74][75][76]. Only little experimental evidence is available to support either of the possibilities listed above.…”

Section: Effect (~T" Nitrate On Phosphate Releasementioning

confidence: 99%

Biology of polyphosphate-accumulating bacteria involved in enhanced biological phosphorus removal

Kortstee

Appeldoorn²,

Bonting

et al. 1994

FEMS Microbiology Reviews

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Recent research on the process of biological phosphorus removal in lab-scale treatment systems has indicated that: (i) the development of an actively polyP-accumulating bacterial community after the introduction of an anaerobic period may take at least 4 months; (ii) up to 80% of all aerobic bacteria isolated from these communities are able to accumulate polyP; (iii) polyP synthesized by the bacterial communities of lab-scale treatment systems is probably mainly low polymeric, not exceeding 20 P-residues, and this polyP is rapidly degraded during the anaerobic period; (iv) the enzymatic hydrolysis of polyP under anaerobic conditions is accompanied by PHB formation from exogenous acetate, reducing equivalents are provided by the degradation of carbohydrates; and (v) nitric oxide inhibits the release of phosphate under anaerobic conditions in Renpho and F&D sludges. Bacteria belonging to the genus Acinetobacter occur in a wide variety of activated sludges in which enhanced biological phosphate removal is observed. A. johnsonii 210A was studied in detail with respect to the elemental composition of polyP granules, the enzymatic synthesis and degradation of polyP, the regulation of polyP metabolism, and the transport of phosphate. A. johnsonii 210A reflects activated sludge in a number of ways as far as polyP metabolism is concerned but its polyP is highly polymeric and the phosphate efflux rate under anaerobic conditions is relatively low and not increased by exogenous acetate. In addition to Acinetobacter, other polyP-accumulating microorganisms may be involved in biological phosphorus removal. The isolation of polyP-accumulating denitrifying bacteria may well have interesting implications for a new process design in wastewater treatment systems. Further studies on the enzymes involved in polyP biosynthesis and on the uptake and efflux systems of phosphate, potassium, magnesium and lower fatty acids in pure cultures will enlarge our insight in the energetics of the metabolism of polyP. In addition, the regulation of the metabolism of polyP-accumulating organisms needs to be studied in more detail.

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Section: Effect (~T" Nitrate On Phosphate Releasementioning

confidence: 99%

Biology of polyphosphate-accumulating bacteria involved in enhanced biological phosphorus removal

Kortstee

Appeldoorn²,

Bonting

et al. 1994

FEMS Microbiology Reviews

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Phosphorus removal and its influence on metal speciation during wastewater treatment

Yeoman¹,

Lester²,

Perry³

1993

Water Research

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The use of chemicals such as aluminium sulphate and ferric chloride in biological wastewater treatment can achieve excellent phosphorus removals and is well established. Unfortunately employing such precipitants has disadvantages, influencing the anaerobic digestion of and altering metal distribution in the precipitated sludges.In order to study these effects, the two aforementioned precipitants were used at both the pre and co-precipitation stages to generate sludge which was concomitantly digested in laboratory scale apparatus. Two sequential extraction techniques, one based on particle size, the other on chemical selectivity were then applied to raw, activated and digested sludge to determine the complexation of the metals within the sludge matrix. The use of chemically precipitated sludge did influence the process of anaerobic digestion with detrimental effects observed when monitoring suspended solids, volume and methane composition of the gas produced and alkalinity.The proportion of solids contained within each particle size range was also affected.In raw sludge aluminium sulphate increased the concentration of small particles (2.5 ym), while ferric chloride precipitation produced larger particles (>100 ym).This trend was reversed for activated sludge. The anaerobic digestion of both precipitated sludges produced large particles (>100 ym). For the heavy metals Cd, Cu, Ni, Pb and Zn, chemical treatment appeared to shift the distribution throughout various chemical fractions in the sludge. More significantly, aluminium sulphate increased the solubility of both Cu and Pb in raw and digested sludge, while both precipitants appeared to reduce solubility of the other metals in all of the sludges.In terms of particle size, the raw, activated and digested sludges which were chemically treated contained metal complexes which were generally larger than the control sludges, although Cu and Ni appeared to be associated with smaller particles.In order to cut the cost of chemical treatment and reduce the environmental impact of precipitated sludges emphasis has been placed on the use of microorganisms to take up phosphorus in excess of normal metabolic requirements during activated sludge treatment.In an attempt to produce a working system two modified laboratory scale activated sludge units, one test and one control, were designed and constructed specifically for excess biological phosphorus removal. Once operational, several modifications were executed on the test unit to enhance the removal of phosphorus.These included improvement of anaerobic conditions; augmentation with acetate and Ac inetobacter/Aeromonas species; increases in sludge age and temperature.The major factor found to influence phosphorus removal was temperature: a 1°C increase resulted in a 2.6% increase in phosphorus removal in the 12-25°C temperature range. During periods of high phosphorus removal experiments were undertaken using metabolic inhibitors to identify the mechanism involved. It appeared that removal was dependent on some physio...

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Carbon Flow and Effluent Variability in Phosphorus-Accumulating Activated Sludge Cultures

Bordacs

Chiesa

1987

Biological Phosphate Removal From Wastewaters

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Effect of Variable Influent Loading on Biological Phosphorus Removal

Cited by 4 publications

References 15 publications

Biology of polyphosphate-accumulating bacteria involved in enhanced biological phosphorus removal

Biology of polyphosphate-accumulating bacteria involved in enhanced biological phosphorus removal

Phosphorus removal and its influence on metal speciation during wastewater treatment

Carbon Flow and Effluent Variability in Phosphorus-Accumulating Activated Sludge Cultures

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