Resources from wastewater – separation at the source
As with waste recycling, resources can be recovered more efficiently from wastewater if the different wastewater streams are no longer mixed. To separate urine from blackwater (faeces, flush water and toilet paper), a urine-diverting toilet or NoMix toilet is used. This separates the two wastewater streams directly in the toilet bowl, but does not differ in use from a conventional toilet. Moreover, waterless urinals can be used to collect urine separately. When showering, washing or doing the dishes, only slightly polluted wastewater is produced. If this greywater is collected separately and not mixed with heavily polluted wastewater from the toilet, new possibilities are opened up.
Urine: Recycling nutrients and making fertiliser
Humans excrete large amounts of nutrients – such as nitrogen, phosphorus and potassium. Most of them are contained in urine. At the same time, these nutrients are the same as those contained in fertilisers. To obtain fertiliser from urine, it is first stabilised and thus loses its pungent odour. In a further step, micropollutants are filtered out and finally the fertiliser is distilled to reduce the volume. The fertiliser can now be used in gardens or agriculture for food production, thereby closing the nutrient cycle.
Greywater: Cleaning and reusing wastewater for the kitchen and bathroom
Clean water can be recovered on site using various methods from the only lightly polluted greywater that is produced when showering, washing or doing the dishes. Depending on its quality, this water can be used locally in the building or neighbourhood for flushing toilets, showering or irrigation. It is important that the processes are robust and that hygiene is ensured at all times.
Blackwater: Generating energy from faeces
Wastewater from the toilet is called blackwater and contains faeces, flushing water and toilet paper. Faeces mainly consist of organic material that is suitable for energy recovery, for example in the form of pellets. In addition to energy, soil conditioner, fodder for farm animals or water can also be recovered from the faeces.