Concentrate management for integrated MBR-RO process for wastewater reclamation and reuse-preliminary tests

Brine generated from membrane filtration processes is becoming an important concern. Indeed, untreated or improperly managed concentrate can lead to serious negative effects in the environment. As some other flow configurations of RO systems, concentrate recirculation allows to reduce the brine generation. In this study, a high system water recovery and concentrate retention was achieved with the additional advantage of a reduced membrane water recovery, which minimizes the fouling effects of the increasing concentration of the solution being passed through the membrane. Solute rejections and permeate quality were not significantly affected by the different concentrate retention ratios and by the increasing salinity concentration of the solution in the feed tank during three hours of experiments. However, highly concentrated feed water can damage membranes and reduce its performances. Hence, with this configuration, the process have to be interrupted when the salt concentration in the feed tank reach a certain level.