NITRIFICATION KINETICS IN ACTIVATED-SLUDGE WITH BOTH SUSPENDED AND ATTACHED BIOMASSES

A series of nitrification kinetic tests was carried out with both susp ended and fixed biomasses originated from a combined activated sludge system with a plastic support for biomass growth introduced into the a eration tank (Experimental combined unit - ECU). The results of these batch tests were compared with kinetics calculated from continuously r un pilot plant. It was concluded that nitrification kinetics of both s uspended and attached biomasses were similar and consequently, it was assumed that the percentage of autotrophs is the same in both biomasse s. The kinetics determined in both batch and continuous systems were c omparable. Kinetic constants measured for suspended biomass of the ECU were higher than those reported by the literature, which was attribut ed to an overaeration of the ECU and an energetic mixing