The Mediterranean basin is one of the poorest regions in the world in terms of water resources. An increased water consumption rate for irrigation purposes along with a high urban population growth, have had an adverse effect on water resources. Thus most groundwater resources in the Mediterranean area are at risk of being exhausted through overexploitation. With limited renewable water resources, most countries of the area have been driven to reuse their wastewaters. However, specially in the east and nort hern Mediterranean regions, wastewaters are inefficiently treated or even re-used directly without treatment for irrigation or sanitary purposes, serving as a carrier for diseases or causing water pollution when discharged to water bodies.In the last decad e, several water treatment technologies have been used in the region with little success on pathogens removal. Membrane bioreactor technology is a very promising alternative to those conventional water treatments for membranes act as a barrier against bact eria and viruses achieving a high degree of water depuration. However, most membrane bioreactors currently in use have very high running costs because of the high-pressure drop and high air-flushing rate required for their operation. The objective of this project is to study a new approach to the operation of membrane bioreactors. This study will include a comparison of the three leading hollow membrane technologies. The operating procedure to be studied is expected to yield very low energy consumption and reduced maintenance costs. These characteristics would make the bioreactors working in these conditions suitable to be operated in peri-urban areas of the Mediterranean basin, where expenditure in public services is a critical factor.