Showing papers on "Enhanced biological phosphorus removal published in 1986"

Metabolic behaviour of Acinetobacter spp. in enhanced biological phosphorus removal - a biochemical model

Abstract: A biochemical model is presented that explains the behaviour of Acinetobacter spp. in enhanced biological phosphorus removal activated sludge systems. The model modifies and extends the proposals of Comeau et al. (1985). Two key parameters are identified in controlling poly-P and PHB synthesis and degradation, the ATP/ADP and NADH/NAD ratios. The predicted behaviour appears to be consistent with that observed.

Biological phosphorus removal: a technology evaluation

Abstract: L'etude de quatre installations de traitement montre que la nitrification et la denitrification sont compatibles avec une teneur en phosphore dans l'effluent de 1 mg/l ou moins

Excess biological phosphorus removal in the activated sludge process using primary sludge fermentation

Abstract: This paper examines the role of short-chain volatile fatty acids in the excess biological phosphorus removal mechanism of the activated sludge process. The effectiveness of various substrate additions in inducing phosphorus removal was investigated through a series of laboratory and pilot-scale experiments. Phosphorus release and substrate uptake both take place in the anaerobic zone of the process and there appears to be an exchange phenomenon that occurs between the two molecules. The system phosphorus removal of the process is improved by the addition of sodium acetate to the anaerobic zone. It is important that the zone receives no incoming nitrate, as the added substrate will be oxidized in the denitrification reaction, rendering it unavailable for the phosphorus removal mechanism. Acetate and propionate, the two substrates that are most effective in inducing anaerobic phosphorus release, can be generated on-site at a treatment plant by primary sludge fermentation in concentrations sufficient to sign...

The Effect of Grazing by a Ciliated Protozoan on Phosphorus Limitation of Heterotrophic Bacteria in Batch Culture1

Abstract: . The yield of the bacterium Enterobacter aerogenes and the ciliate Colpidium colpoda was dependent on initial phosphorus concentrations in batch cultures containing 125 or 250 mg/liter glutamate and 50–1000 μg/liter phosphorus. For both, yield per unit phosphorus declined at higher phosphorus concentrations. A marked decline in growth rate in bacterial cultures was coincident with the depletion of dissolved phosphorus and the development of rapid orthophosphate turnover times. Colpidium introduced to these cultures consumed about 16,000 bacteria/h/ciliate while multiplying exponentially and relieved phosphorus limitation, as indicated by a longer turnover-time for phosphate. The longer turnover-time was due to the reduction of bacterial numbers; in cultures with ciliates, bacteria appear to be more active in taking up phosphate, and much of the total phosphorus accumulates in ciliates. Ciliates released both inorganic and organic phosphorus, but the organic phosphorus did not accumulate to excess in the cultures to an extent that would indicate that it is less used by bacteria. Although ciliates release enough phosphorus to account for ca. 20% of the bacterial uptake, ciliates appear to behave as phosphorus sinks as much as phosphorus recyclers in these closed systems.

Method for reduction of sewage sludge from sewage clarification plants

Abstract: Sewage sludge from an activated sludge system in a sewage clarification plant is reduced by converting at least a part of the organic mass of the sludge into a biologically degradable form by treating the sludge with an acid at a pH of from about 0 to about 2, at an elevated temperature and at an elevated pressure. The dissolved organic mass shows an excellent biological degradability.