The existing treatment plant at Sharjah municipality needed an upgrade to handle increased flow and stringent demands. The target was to find a solution without need for introducing any additional volumes and able to handle as much hydraulic load as possible on the existing clarifiers. MBBR technology was chosen and the hydraulic capacity of the existing activated sludge plant was increased from 37.000 m3/d to 53.000 m3/d. Located in the United Arab Emirates the municipality of Sharjah has seen a very rapid development and increased population during the last years. With a significant portion of the wastewater being collected by tankers from small businesses, MBBR process has proven to be very successful.