PURATREAT: New energy efficient approach to the operation of Membrane Bioreactors for Decentralised Wastewater Treatment
Water scarcity is a problem faced by all the countries of the Mediterranean area to some extent. In particular, the EU Water Initiative has identified the Southern Mediterranean as the area of highest water stress in the world. The region, with a very young and still fast-growing population, has the lowest per capita availability of water and the highest actual use of all potential freshwater resources. Most wastewater produced in urban areas of the region is inefficiently treated due to poor maintenance of the equipment and high cost of electricity (in Morocco for example, 60% of activated sludge plants are out of order [CSEC 2001]). The majority of the treatment plants in the area use activated sludge processes, followed in some cases by rapid sand filtration. These techniques were developed to reduce the suspended matter load and oxygen demand of the discharged reclaimed waters and to reduce eutrophication of the bodies of water, but not designed to remove pathogenic excreted micro-organisms. In rural and remote areas, the population have practically no access to water sanitation, whereby wastewater is directly discharged into water bodies or re-used for irrigation without treatment, thus spreading water-borne diseases and causing eutrophication and pollution of water resources.
Membrane bioreactor technology is a very promising alternative to those conventional water treatments as membranes act as a barrier against bacteria and viruses achieving a high degree of water purification. 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.
- Schematic of a submerged MBR system (Kubota/EIMCO)
The objective of this project is to study a new approach to the operation of membrane bioreactors. This study will include a comparison of three leading 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.
- Membrane bioreactor with submerged modules
The Puratreat Project is an EC-funded research initiative which aims to study the application of Membrane Bioreactors as an alternative to the conventional treatment of urban wastewaters in the Southern and Eastern Mediterranean regions.
