We develop, test, and study a novel osmotic membrane bioreactor to convert sewage into clean water and bioenergy. The system holds great promise as a sustainable wastewater treatment technology for the protection of aquatic environment. It can be used in both developing and developed worlds. It is highly attractive in terms of treating wastewater to meet the further stringent water quality standards, reduced footprint and reduced energy costs. More importantly, it has the potential to make sewage treatment a net energy producer.