Applications of submerged and staged membrane systems for pollutant removal from effluents and mechanism studies - a review

Membrane based filtration is one of the promising technologies for rehabilitation of wastewater streams for reuse and recycle. Many advancements have emerged with the use of novel materials and innovative integrated technologies. The present investigation focuses on the treatment methods based on submerged and stages systems of membranes for water purification. Ceramic, polymeric and mixed matrix type of membranes fabricated for specific type of effluents, their modification methods for accelerating the rejection efficiency, permeability, durability, stability and antifouling properties are detailed in this review. Graphene oxide is the most considered membrane material for adsorption purposes as it exhibits larger surface area, abundant functional groups contain oxygen and has good supply of ligands which is responsible in metal adsorption as it enhances electrostatic interaction by bonding metal ions with graphene oxide nanosheets. Energy derivation in terms of biogas production was also reported in some integrated methods. In many cases, embedded nanomaterial matrices yielded maximum efficiencies in both the submerged and staged operations. However, submerged type of membranes are reported more than the staged type due to simpler configuration with relatively lesser equipment, operational and maintenance issues. In treatment of a low strength wastewater, aluminum oxide based membrane in fluidized bed assembly was reported to yield promising results with reduced power requirement.

Automated summary

Membrane based filtration technology is a promising approach for the rehabilitation of wastewater for reuse and recycle. This review focuses on the treatment methods using submerged and staged systems of membranes for water purification. Different types of membranes, such as ceramic, polymeric and mixed matrix membranes, are discussed in detail, along with their modification methods to improve rejection efficiency, permeability, durability, stability and antifouling properties. Graphene oxide is highlighted as the most considered membrane material for adsorption purposes. Additionally, the use of embedded nanomaterial matrices in both submerged and staged operations has shown maximum efficiency. Overall, submerged membranes are more commonly used due to their simpler configuration and lower operational and maintenance issues.