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Activated sludge is the common name of the suspended-growth biological processes used for the treatment of domestic and low-to medium-strength industrial wastewater. Activated sludge provides the conversion of organic matter into microbial culture, and then reproduced biomass is easily separated by gravity settling. Thereby organic matter content is eliminated from the influent. Activated sludge also provides adequate biological pathways for the elimination of nitrogen and phosphorus nutrients from wastewater by applying advance treatment methods [1-7]. The usual forms of phosphorus nutrients found in aquatic environments include orthophosphate, polyphosphate, and organic phosphate. Phosphorus compounds undergo hydrolysis and are converted to

in Wiley InterScience (www.interscience.wiley.com).The magnitude of excess particulate matter separation from a flocculated suspension at upflow settling conditions was predicted from the concentration distribution of batch settling data. The settling data pairs were fitted to modified population-growth model. Settling surfaces at upflow operation were increased by inlaying pipes into the column and inclining it for 508, 608, 70 and 808 coinciding with 0.5563, 0.7152, 1.0455 and 2.0594 mm/s decreased surface hydraulic loading rates, respectively. The respective removal ratios observed at the applied loadings were 0.878, 0.848, 0.756 and 0.520, while the corresponding predicted efficiencies by mean value method were 0.865, 0.831, 0.773 and 0.512, respectively. It was demonstrated that removal predictions obtained from the batch settling tests were quite compatible with the observed removals of actual upflow operation. The investigation also demonstrated that concentration distribution of batch settling data heads successfully to predict the excess particulate matter removal at upflow settling.