Removal of Suspended Solids Using Pumice Stone in Integrated Fixed Film Activated Sludge Process

Wastewater treatment plants operators prefer to make adjustments because they are more cost effective, to use the existing tank instead of building new ones. In this case an imported materials would be used as bio-loads to increase biomass and thus maintain efficiency as the next organic loading increases.In the present study, a local substance "pumice stone" was used as a biological carrier in the aeration tank, and the experiments were carried out in five stages: without biological carriers, filling ratio of 4%,10%,20%, and25% with pumice stone, the maximum organic loading at each stage (1.1884, 1.2144, 1.9432, 2.7768, 3.3141)g BOD /l.d respectively.Other experiments were carried out to determine the best filling ratio, the SS removal ratio was (67.57%, 69.5%,79.44%,89.61%,and 99.2%) when the filling ratio with pumice stone was (0, 4, 10, 20, and 25)% respectively, at organic loading 2 +/- 0.0528 g BOD /l.d, so the best filling ratio of pumice stone was 25%.