A review of membrane bioreactor potential for nitrate removal from drinking water

Continually elevated drinking water nitrate concentrations worldwide have increased focus on alternative nitrate removal processes accentuated by the limitations of current solutions, namely cost and complex waste generation. Biological denitrification is a comparatively low cost option, though its poor retention of bacteria and requirement for external carbon necessitates further downstream processing. To eradicate the associated disadvantages, the biological process can be integrated with membrane technology. Subsequently several membrane bioreactor (MBR) configurations have been trialled for this duty. Although the science behind each configuration has been justified, issues related to secondary contamination of the product water remain and require further investigation. This paper reviews the research to date appraising advantages and disadvantages associated with each configuration whilst also identifying areas that require further research and consequently assessing which nitrate removal MBR technologies will prevail for the future.