ABSTRACT

The application of micro-carriers such as sand, activated carbon, and coke in modifying the activated sludge systems has resulted in “fluidized bed systems” 1 and “carrier activated sludge systems.” 23 The presence of these micro-carriers in the activated sludge reactors provide a significant surface area (10,000 to 100,000 m 2 /m 3 of carriers) for the formation of biofilm and thus aids in retaining a high concentration of biomass in the reactors.