Two membrane bioreactor configurations, the pressure-driven membrane bioreactor and the ion exchange membrane bioreactor (IEMB), were tested for the removal of toxic oxyanions from drinking water. The results based on a case study - nitrate removal at a treated water production rate of 30 L m-2 h-1 - showed that in both bioreactors the desired water quality in terms of nitrate and nitrite can be achieved. The pressure-driven membrane bioreactor allows for possibly higher water production rates and uses relatively cheaper membranes, however, the water quality control in terms of TOC requires on-line monitoring and a strict regulation of the carbon source addition. This configuration also requires an initial start-up period before achieving a steady state operation because the water and microbial culture are in direct contact. The ion exchange membrane bioreactor offers the advantage of selectively removing the target anion and producing TOC-free water with practically no initial start-up period. Due to the physical separation of the microbial culture from the water stream, the very low diffusion coefficient of ethanol through the Neosepta ACS membrane used, and the membrane-attached biofilm acting as an additional reactive barrier to ethanol penetration, secondary pollution of the treated water was avoided. The development of cheaper anion exchange membrane (possibly in a hollow fibre form) would make the IEMB process economically competitive.
|Number of pages||5|
|Publication status||Published - 1 Jan 2007|
- Dialysis DD