Wastewater represents a potent source of energy which currently is underutilised. Industries such as food and beverage production, breweries, wineries or biofuel producers currently expend around USD15 billion worldwide for wastewater treatment, where energy and toxic chemicals and/or slow biological processes need to be used. This wastewater contains biosourced contaminants which could be used as a fuel to generate renewable electricity at almost no cost. We have developed a technology that can harvest this energy and at the same time decrease the contamination. The benefit of this technology is both generation of affordable electricity and money savings from lower water treatment costs. Unlike biological processes our electrochemical system does not contain microbes, which are sensitive to the water conditions, need close process control and expert knowledge. It is basically a “plug and play” process. Another benefit over current biological solutions is that it requires only 1% of the space of a biogas facility, so even companies with little space can implement it. The total renewable electricity produced and the energy saved for wastewater cleaning has the potential to save millions of tons of CO2, thus helping to mitigate climate change.