Wastewater contains organic matter and the three main nutrients for plant production: nitrogen, phosphorus and potassium. Nitrogen fertilizer is energy consuming to produce and phosphorus is a limited mineral resource. Scandinavia is pioneering sustainable solutions to wastewater treatment. Source separation (blackwater/greywater) systems produce almost zero emissions and open up exiting urban applications of sanitation options in order to close the loop.JENSSEN, P.D. VRAALE, L. LINDHOLM, O. SENG, L. (2007): Sustainable Wastewater Treatment. In: SENG, L. (2007): Proceedings of the International Conference on Natural Resources and Environmental Management and Environmental Safety and Health. Norway: .