Membrane-Based Technologies for the Up-Concentration of Municipal Wastewater: A Review of Pretreatment Intensification

Municipal wastewater has a high content of recoverable energy, distributed within particulate and soluble organic matters. It is estimated that the anaerobic treatment of that content and the recovery of biogas energy could supply at least enough power to render a wastewater treatment plant electrically self-sufficient. Therefore, an intensification of wastewater pretreatment could separate and concentrate the organic matter in order to improve the anaerobic stabilization of both the solids and the water streams. In light of this, membrane-based processes have been considered as novel technologies in order to recover carbon from municipal wastewater. In this work, direct membrane filtration, forward osmosis and dynamic membrane have been reviewed as possible membrane-based technologies for the up-concentration of wastewater. A literature overview has been performed in order to elucidate the main operational parameters and to compare the advantages and downsides of every pretreatment reported up until now.