DYNAMICS OF PHOSPHORUS AND ORGANIC SUBSTRATES IN ANAEROBIC AND AEROBIC PHASES OF A SEQUENCING BATCH REACTOR

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch rea ctor (SBR). The synthetic feed used was based on peptone and glucose a s organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991), The experimental work w as divided into two runs, each characterized by different operating co nditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulati ng and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called ''G bacteria''. The results obtained seem to be inconsiste nt with the general assumption that the G bacteria are characterized b y anaerobic substrate uptake not connected with any polyphosphate meta bolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as Organic substrates show that the role of acetate in th e biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.