The membrane bioreactor (MBR) is a new technology in wastewater treatment that is increasingly gaining popularity and application around the world due to its numerous advantages over conventional biological treatment (Stephenson, Simon, Jefferson & Brindle, 2001). It comprises of a suspended growth-activated sludge biological treatment followed by membrane filtration for liquid / solid separation. The need for processes like sedimentation and disinfection used in conventional processes is eliminated through the MBR systems. The typical advantages of MBR include reduced footprint, low sludge production / less sludge handling and excellent effluent quality which can be reused / recycled. The complete sludge retention with the MBR allows high biomass concentration and retention of microorganisms such as nitrifying bacteria in the bioreactor. This facilitates a stable treatment performance and a very low sludge production at high hydraulic loads (Muller, Stouthamer, Verseveld & Eikelboom, 1995). The effluent can be reused directly for non-potable purposes due to high-quality final effluent with effluent solids concentrations less than 1 mg/L (WEF, 2006).
MBR technology is however yet to gain much popularity in Kenya as preferred treatment method over conventional treatment methods for industrial and domestic wastewater treatment. Apart from the University of Nairobi Tower MBR Plant, the Supplier (Allied Utilities Services) has also installed the MBR Plants in English Point Marina, First Community Bank, 21st Century Hotel, Ole Sereni Hotel, Kibos Sugar and Allied Limited and among others (Project Documents).