Factors Affecting Biological Removal of Phosphorus

Abstract

A pilot plant study on biological removal of phosphorus was conducted over fifteen months to obtain optimum operational conditions and evaluate process performance. The pilot plant was composed of an anaerobic zone followed by an aerobic zone, and had a capacity of treating 100 m3 municipal wastewater per day. In the anaerobic zone, BOD loading rates and BOD to MLSS ratios were found to be important factors. In the aerobic zone, on the other hand, the hydraulic retention time had a significant influence on the phosphorus removal efficiency. For successful removal of phosphorus, a shorter hydraulic retention time in the aerobic zone along with appropriate parameters in the anaerobic zone (BOD loading rate ≦ 2 kg-BOD/kg-MLSS day, BOD to MLSS ratio ≦ 0.1 kg-BOD/kg-MLSS) are essential.

Metagenomic characterization of ‘Candidatus Defluviicoccus tetraformis strain TFO71’, a tetrad‐forming organism, predominant in an anaerobic–aerobic membrane bioreactor with deteriorated biological phosphorus removal

“…Although these capabilities allow PAO to dominate in EBPR systems, phosphorus removal can deteriorate. This often coincides with a microbial community shift from PAO to 'glycogen-accumulating organisms' (GAO), a competitor that can cyclically accumulate PHA and glycogen (Fukase et al, 1985;Cech and Hartman, 1990;1993;Liu et al, 1996).…”

Glycogen-accumulating organisms in laboratory-scale and full-scale wastewater treatment processes b bThe GenBank accession numbers for the sequences reported in this paper are given in Methods.

“…GAOs have been reported to dominate deteriorated EBPR processes where glycogen and PHA transformations are similar to those during good EBPR but P is not transformed as in PAOs (e.g. Fukase et al, 1985 ;Satoh et al, 1994). Very little is known of GAOs apart from their phenotype.…”

The elemental compositions of P-accumulating microbial granules developed in sequencing batch reactors

“…Although full-scale experiences showed a strong potential of EBPR, difficulties in assuring stable and reliable operation have also been recognized. Process failure of biological phosphorus removal not only in the laboratory, but also in full-scaled plants often happened without understanding of the exact reasons [4][5][6]. How to improve the efficiency and stability of EBPR process is a technical challenge in the area of wastewater treatment.…”