Today's gold standard for wastewater management is a sewer system with a centralised wastewater treatment plant. However, this system has its limits, because it requires large amounts of water and an extensive infrastructure. An alternative are small, highly efficient decentralised reactors, which allow a more flexible wastewater management. We develop processes, which can be used for such wastewater treatment plants. We use the following three principles as guidelines:
Separation at the source: Waste streams with different compositions should be treated separately according to their properties.
Decentralisation: The waste streams should be treated as closely to the source as possible, thereby minimising resource consumption and environmental pollution.
Resource recovery: The treatment should focus on recovering the resources contained in the waste streams.
The three most important domestic wastewater streams are urine, faeces and greywater. So far, our research has been mainly focused on urine, because it contains most of the nutrients. A careful management of nutrients not only reduces environmental pollution (e.g. eutrophication), but it also allows closing the nutrient cycle with agriculture.
We work closely together with the other research groups within the ENG department in order to develop optimal resource recovery processes. Strong links also exist with other Eawag departments and national and international research units to cover the various aspects, which have to be considered when implementing new wastewater treatment and sanitation systems.