PURATREAT is a Specific Targeted Research Project for international Cooperation with Mediterranean Countries (INCO-MED) with a duration of 3 years and funded by the European Commission, which aims to develop a method for decentralized wastewater treatment that allows the re-use of water with minimal operational and maintenance costs. This project will study the most suitable MBR wastewater technology to be applied to peri-urban areas of the southern Mediterranean and Middle East countries. Basically, membrane bioreactors comprise an activated sludge tank in which membrane filtration modules are immersed. The membranes allow the water to go through but keep the solids inside the bioreactor, reaching high biomass and pollutant concentrations and thus favouring biodegradation. A laboratory test membrane bioreactor will be built in order to study and compare the performance of the three leading membrane technologies operated in a way, which is expected to produce low maintenance and operation costs. Therefore, this project will initiate a new approach to operating MBR systems adapted to the financial constraints affecting Southern Mediterranean and Middle East peri-urban or rural communities. The consortium will study the performance and feasibility of the bioreactor working at minimum aeration rate and short solids retention time, operating conditions that, if proved effective, would allow the adoption of this kind of technology as a cost-effective decentralised wastewater treatment solution. In addition, the construction and running costs of a potential full scale decentralised wastewater treatment plant will be contrasted with the investment capacity available to several Mediterranean peri-urban areas in North Africa and the Middle East, where expenditure in public services is a critical factor.

Duration: 2005-2008

Budget: (estimated) 1.150.824 €

Partners:

• TECHNOLOGIE-TRANSFER-ZENTRUM BREMERHAVEN (Germany) - Coordinator
• CENTRE DE BIOTECHNOLOGIE DE SFAX (Tunisia)
• UNIVERSITY OF BATH (Germany)
• UNIVERSITY CADI AYYAD (Morocco)
• AL-BAATH UNIVERSITY (Syria)
• EUROPEAN MEMBRANE INSTITUTE (Netherlands)
• OFFICE NATIONAL DE L'ASSAINISSEMENT (Tunisia)
• SOCIEDAD GENERAL DE AGUAS DE BARCELONA (Spain)
• THE INTER-ISLAMIC NETWORK ON WATER RESOURCES DEVELOPMENT AND MANAGEMENT (Jordan)
• BIOAZUL S.L. (Spain)
• KING SAUD UNIVERSITY (Saudi Arabia)

Main strategic objectives of the PURATREAT project:

• To open the way to the adoption of cost-effective decentralised wastewater treatment plants in the Mediterranean partner countries
• To assist in the preservation of water resources thus contributing to the sustainable development in the Mediterranean region.
• To foster membrane technology for wastewater treatment on both sides of the Mediterranean.
• To initiate an international forum for MBR researchers from the EU and non-European Mediterranean countries.

• to compare the performance of MBR bioreactor's working under conventional operating conditions with the performance achieved under conditions specially adapted to the requirements of MENA countries.
• to compare the performance the most advanced membrane technologies available in the market working in different operating conditions.
• to study the performance,energy consumption and maintenance requirements of MBRs working at low Solids Retention Times as a possible operating procedure for the application of these system in peri-urban areas of MENA countries.
• to study the characteristics of the microbial community present in the reactor for the different at the experimental conditions studied
• to propose the most suitable technology for the application of decentralised MBR wastewater systems and its optimum operating conditions
• to study the feasibility of decentralised wastewater treatment plants based on MBR technologies in the MPC countries

Background:
The traditional solution for decentralized wastewater treatment in the Mediterranean region was just to use cesspits or septic systems. This system is very simple but it is only acceptable for very small groups of houses and under very well defined conditions on the receiving soil (determined soil permeability, certain depth to the water table, etc). This system can lead to groundwater contamination, foul odors and it does not allow for safe water re-use to any extent. A more efficient system is activated sludge plants and SBR (Sequencing Batch Reactor, a modification of the latest one). This process is based on the aerobic digestion of wastewater with flocculating biological growth, followed by separation of treated wastewater from this growth. These systems are fairly efficient in general, although they produce bulky sludge, provide insufficient disinfection for water reuse and have high-energy consumption.
The most efficient treatment in terms of energy consumption and water purification is the membrane bioreactor's (MBR), which comprises an activated sludge tank in which membrane filtration modules (either micro filtration or ultrafiltration) are submerged. It has been proved that this system is the only one that can guarantee a germ-free effluent which can be reused with total safety for technical purposes (such as toilet flushing) and which at the same time does not produce toxic compounds (such as chlorination).
In general, the problem with all existing membrane bioreactor's is related to the characteristics of the membranes and to the way the bioreactor are operated. It has been proved that these components display low flow rates and are prone to clogging by accumulation of organic material, requiring continuous air pumping to clean the membranes, which means considerable energy consumption. In the long term, fouling in the membranes boundary zone has been identified as another significant disadvantage of this treatment method, what implies the use of chemicals to clean the membrane or even the replacement of these ones. Moreover, high mechanical stress caused by aeration can break off the capillaries. All these problems lead to increased maintenance needs, high energy consumption, frequent membrane replacement and sometimes increased organic loads and germs in the effluent (when the membranes rip off). In this project three different types of state-of-art sub-merged hollow-fiber membrane modules will be tested and compared under different operating conditions.
PURATREAT will help ensure European research competitiveness in the field of wastewater membrane bioreactor's, enabling the EU as a whole to keep pace with the innovations developed in MBR technology coming from the United States, Canada and Japan, the three leading producers of innovation in the field.

Further information can be found on the project website www.puratreat.com.