AWWA MTC53725

The stimulus for research on membrane biosorption was the need to find aneconomic and realistic method for cleaning large water systems containing dilutedmetal ions. The main assumption and philosophy of the idea is to take advantageof natural biological processes enhanced with engineering methods. The paperpresents a new effective separation technique--membrane biosorption, based onintegrated system, which comprises biosorption of metal ions on biomass withultrafiltration. The essential feature of the system is the use of naturalbiomass always existing in a water environment. The membrane's role is to ensurethe proper contact of biomass with the metal ions. This can be achieved with anultrafiltration process when cells are separated on the membrane surface, whereaspermeate with metal ions passes through the membrane. The concept assumes thesynergetic effects that occur at the membrane vicinity due to increasing reagentconcentration. To attain high selectivity with high capacity (flux) of thebiosorption process, the layers must be fully controlled. The film of the biomassmust be permeable and thin enough to ensure high flux. On the other hand thismust be sufficiently compact and dense to entrap all ions passing through it. Themost important feature of the film is its renewal during the process to maintainthe sorption capacity and to avoid saturation with metals. The proper selectionof the membrane type and subsequently, the operation conditions, enables a thinlayer of biomass to form that can be renewed in many ways. Biofilm may beskimmed, swept-out, backflushed or removed prior to saturation. Includes 10 references, figures.