The feasibility of citric acid as external carbon source for biological phosphorus removal in a sequencing batch biofilm reactor (SBBR)

摘要

The aim of this study was to evaluate the feasibility of citric acid as external carbon source for biological phosphorus removal. Citric acid was the only source of organic carbon and biomass occurred only as a biofilm. The effect of varying the duration of the mixing and aeration phases on the process of dephosphatation and consumption of organic substrate was examined. The operation consisted of filling (0.5 h), mixing (2.75-8.25 h), aeration (2.75-8.25 h) and draw (0.5 h) phases. Total phosphorus and nitrogen influent concentrations were 7.02 mg PL-1 and 2.05 mg.N L-1, respectively. Enhanced intracellular accumulation of polyphosphates (poly-P) and their release in reactors with immobilized biomass (SBBR) was stated. The highest rates of phosphates release (0.059 +/- 0.004g P-PO43- m(-2) h(-1)) and phosphates uptake (0.028 +/- 0.002 g P-PO43- m(-2) h(-1)) were observed for mixing to aeration phase duration ratio of 1:3. The percentage of phosphorus in dry matter of biofilm reached 4.6%. (C) 2014 Elsevier B.V. All rights reserved.