Statistical modelling of biological phosphorus removal from wastewater

Abstract

Biological phosphorus removal from wastewater is affected by a range of factors. These are composition of wastewater, environmental, technological factors having impact on biochemical processes and activity of microorganisms. In order to make a complex evaluation of impact of these factors on the BPR applying method of multiple linear regression analysis, it was selected a model that describes impact of factors on the BPR complexly and carried out statistical modelling. According to standardised values of parameters it was determined that the most important variable is the BOD7/TP in influent for the prediction of values of phosphates in aeration zone, and the second most important variable is the temperature of wastewater. The results of statistical modelling showed that to assure required phosphorus removal during the warm period of a year the BOD7/TP in influent shall not be lower than 40 maintaining short sludge age (10, 15 days) and it shall not be lower than 35 maintaining long sludge age (20, 25 days) as in the latter case the temperature decreases seasonally.