Fixed film phosphorus removal – flexible enough?

2006 ◽  
Vol 53 (12) ◽  
pp. 75-81 ◽  
Author(s):  
F. Rogalla ◽  
T.L. Johnson ◽  
J. McQuarrie

While biological phosphorus removal (BPR) has been practised for 30 years, up to recently it has been restricted mainly to activated sludge processes, with the corresponding need for large basin volumes. Yet, research with biofilm reactors showed that the principle of alternate anaerobic and aerated conditions was applicable to fixed bacteria by changing the conditions in time rather than in space. Attached growth enhanced biological phosphorus removal (EBPR) systems are attractive because of their compactness and capability to retain high biomass levels. However, the phosphorus extraction depends on backwashes to enhance the phosphorus-rich attached biomass, and correct control of unsteady effluent quality created by frequently modified process conditions. Accordingly, EBPR remains a challenging task in terms of combining nitrogen and phosphorus removal using attached growth systems. Nevertheless, a combination of activated sludge and biofilm carriers, in the integrated fixed-film activated sludge system, provides treatment opportunities not readily available using suspended growth systems. Current practice is only at the beginning of exploiting the full potential of this combination, but the first full-scale results show that compact tankage and low nutrient results based on biological principles are possible.

1983 ◽  
Vol 15 (3-4) ◽  
pp. 1-13 ◽  
Author(s):  
James L Barnard

This paper briefly summarizes the early work on phosphorus removal in activated sludge plants in the U.S.A. and observed that such removals only occurred in low SRT plants of the plug flow type and in the Phostrip plants, neither designed for full nitrification. The discovery of simultaneous nitrogen and phosphorus removal, as well as full-scale experiments are discussed. The Phoredox process was proposed utilizing internal recycling for the removal of nitrates and an anaerobic first stage in which the incoming feed is used to obtain the necessary anaerobic conditions, essential as a conditioning step for the uptake of phosphorus. Proposed mechanisms are discussed.


2006 ◽  
Vol 41 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Zhe Zhang ◽  
Eric R. Hall

Abstract Parameter estimation and wastewater characterization are crucial for modelling of the membrane enhanced biological phosphorus removal (MEBPR) process. Prior to determining the values of a subset of kinetic and stoichiometric parameters used in ASM No. 2 (ASM2), the carbon, nitrogen and phosphorus fractions of influent wastewater at the University of British Columbia (UBC) pilot plant were characterized. It was found that the UBC wastewater contained fractions of volatile acids (SA), readily fermentable biodegradable COD (SF) and slowly biodegradable COD (XS) that fell within the ASM2 default value ranges. The contents of soluble inert COD (SI) and particulate inert COD (XI) were somewhat higher than ASM2 default values. Mixed liquor samples from pilot-scale MEBPR and conventional enhanced biological phosphorus removal (CEBPR) processes operated under parallel conditions, were then analyzed experimentally to assess the impact of operation in a membrane-assisted mode on the growth yield (YH), decay coefficient (bH) and maximum specific growth rate of heterotrophic biomass (µH). The resulting values for YH, bH and µH were slightly lower for the MEBPR train than for the CEBPR train, but the differences were not statistically significant. It is suggested that MEBPR simulation using ASM2 could be accomplished satisfactorily using parameter values determined for a conventional biological phosphorus removal process, if MEBPR parameter values are not available.


1990 ◽  
Vol 22 (7-8) ◽  
pp. 35-43
Author(s):  
K. D. Tracy ◽  
S. N. Hong

The anaerobic selector of the A/0™ process offers many advantages over conventional activated sludge processes with respect to process performance and operational stability. This high-rate, single-sludge process has been successfully demonstrated in full-scale operations for biological phosphorus removal and total nitrogen control in addition to BOD and TSS removal. This process can be easily utilized in upgrading existing treatment plants to meet stringent discharge limitations and to provide capacity expansion. Upgrades of two full-scale installations are described and performance data from the two facilities are presented.


1994 ◽  
Vol 29 (7) ◽  
pp. 153-156 ◽  
Author(s):  
D. Wedi ◽  
P. A. Wilderer

Most of the fundamental processes responsible for enhanced biological phosphorus removal (EBPR) were obtained through laboratory tests under defined conditions with pure or enriched cultures. Acinetobacter sp. was identified as the most important group of bacteria responsible for bio-P removal. Full scale data showed, however, that laboratory results do not match full scale results well enough. There is a lack of data on the effects of sub-optimal process conditions such as inadequate availability of volatile fatty acids (VFA), high nitrate recycle, storm water inflow or low temperatures. In this paper the results of full scale experiments on P-release are presented and compared with theoretical values. Measurements at a full scale Phoredox-system showed a surprisingly low P-release in the anaerobic reactor. Only 4 to 10% of the phosphorus in the activated sludge was released in the bulk liquid. With laboratory batch-tests, a maximum of 20% of the P in the sludge could be released. It is assumed that under the prevailing process conditions either the fraction of Acinetobacter sp. was very small, or bacteria other than Acinetobacter sp. were responsible for the P-removal, or most of the phosphorus was bound chemically but mediated by biological processes.


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