How sludge is processed has a major impact on the efficiency and the cost of a system. Disposing of sludge is one of the highest expenses of a treatment plant. Sewage sludge is the only on-site energy source for a treatment facility. Many sewage treatment plants already make use of the sludge. Combined heat and power plants convert the digester gas into electricity and heat. Sludge can do much more, however. It offers a great deal of potential as a source of nutrients. Experts categorise the recovery of plant-available phosphate in particular as profitable (for more information, see Solutions - Nutrient Recovery). We have the right technology. It enables us to achieve three objectives: The reduction of the amount of sludge, its use as an energy resource and as a source of phosphorus. It is not only possible to improve significantly the energy balance of wastewater treatment plants; the goal of energy self-sufficiency is within reach.