A critical review on membrane hybrid system for nutrient recovery from wastewater

Wastewater has been investigated as a source for nutrient recovery for two reasons: firstly it contains a high concentration of nutrients; and secondly, it exists in large quantities. Recovering nutrient from wastewater can minimize the environmental footprint of wastewater treatment; simultaneously, the recovered nutrient can be added to fertilizer production to ensure food security. The membrane technique integrated with chemical and biological processes as a membrane hybrid system is a promising method to recover nutrient from wastewater since the membrane can enrich nutrient. It can subsequently increase the technical and economic feasibility of the nutrient recovery process. For this reason, this paper comprehensively and critically reviews the current state of the membrane hybrid system for nutrient recovery from wastewater. Membrane hybrid systems consisting of membrane-based hybrid systems and membrane bioreactor (MBR)-based hybrid systems are explained with reference to their general features, such as mechanisms and processes. Furthermore the advantages and challenges of the membrane hybrid systems are compared as well as their economic feasibility. Future research avenues into membrane hybrid systems are suggested and what can the system more accessible.