An analysis of the factors that influence biological phosphorous removal (BPR) in a sequencing batch anaerobic/aerobic reactor

A sequencing batch anaerobic/aerobic reactor was operated in such a manner as to simulate typical variations in loading and influent feed composition as might be encountered in an urban wastewater treatment plant. The impact of these Variations on biological phosphorous removal (BPR) was assayed using a number of statistical techniques including simple regression, multiple regression, ANOVA and factorial analysis. The results demonstrate the importance of biomass loading on efficiency and relate this to the level of mixed liquor suspended solids retained within the system. The ratio of COD:P in the influent wastewater had no significant impact on removal. Multiple regression analysis of factors associated with the release of phosphorous in the anaerobic phase revealed a strong correlation of these factors with subsequent phosphorous uptake efficiency in the aerobic phase. On the basis of the coefficients derived from the analysis an equation was proposed which showed a good fit to experimental data on BPR.