This project examines how the opconcentreren of domestic waste water with organic waste or by-products can increase the energy efficiency of wastewater treatment plants. The approach could even lead to an energy in the purification of contaminated wastewater. Objectives In Flanders, all the infrastructure for the treatment of domestic waste water already present and based on activated sludge systems. A complete turnaround in treatment concept in the short term is not feasible. It should therefore be considered more opportunities to optimize existing systems. By co-digestion of organic waste in the sludge digest ears, the amount of produced biogas can be increased and could obtain an energy-neutral system. Elsewhere in the world, the challenges are great to provide fast-growing and / or new cities of the necessary infrastructure for sewage treatment, waste collection and treatment. May be involved in the development of urban development projects or new concepts for combined treatment of wastewater and waste. To arrive at a correct sizing and cost estimation are obviously larger scale longer term testing is essential. This project therefore an object of the testing on a larger scale (demonstrator) of the SewagePlus approach, which refers to the combined treatment of waste waters and waste streams with a central role for fermentative processes. Both the regional and international arena, is supplying organic streams needed. Therefore, will first be made a proposal of the currents that can be tested. Furthermore, various techniques for upconcentration of sewage water will be examined. Finally be evaluated different flow scenarios of organic streams. The research for the Flemish situation existing water treatment infrastructure will focus on optimizing the codigestieproces. Because large-scale sludge fermentation is already being applied, the co-fermentation test on a pilot scale will be carried out. For new infrastructure, worked on the scale of the first step of SewagePlus concept, namely an acid fermentation. Finally set out a number of scenarios for the SewagePlus approach whose energy consumption, environmental impact, etc. compared to conventional wastewater treatment through Life Cycle Assessment (LCA). The scenario is best revealed by the LCA will be designed to final for an industrial application.