RESUMEN
Wastewater treatment was primarily implemented to enhance urban hygiene. Treatment methods were improved to ensure environmental protection by nutrient removal processes. In this way, energy is consumed and resources like potentially useful minerals and drinking water are disposed of. An integrated management of assets, including drinking water, surface water, energy and nutrients would be required to make wastewater management more sustainable. Exergy analysis provides a good method to quantify different resources, e.g. utilisable energy and nutrients. Dilution is never a solution for pollution. Waste streams should best be managed to prevent dilution of resources. Wastewater and sanitation are not intrinsically linked. Source separation technology seems to be the most promising concept to realise a major breakthrough in wastewater treatment. Research on unit processes, such as struvite recovery and treatment of ammonium rich streams, also shows promising results. In many cases, nutrient removal and recovery can be combined, with possibilities for a gradual change from one system to another.