Urine contributes only 1% to the volume stream of conventional domestic wastewater, however it contributes to about 80% of the N load and 50% of the P load. One person produces on average 1.5 L of urine per day, which contains about 9.1 g N /L and 1 g P /L. These high nutrient concentrations in urine make it possible to develop more effective and energy efficient recovery technologies. Separation of urine from other wastewater streams is therefore an interesting option to keep these valuable nutrients concentrated in order to develop a suitable nutrient recovery concept.
Based on this knowledge, European research groups started investigating treatment options for so called “source separated urine” starting in the 1990s (Kirchmann and Pettersson, 1995; Larsen and Gujer, 1996) in order to promote sustainability of wastewater management. Source separation of urine means that a dilution with other wastewater streams is prevented by using for example special urine separation toilets and urinals. Source separation projects have been demonstrated on various scales.
For example, in Sneek (The Netherlands) the Decentralised Sanitation and Reuse concept has been successfully demonstrated for 32 households by a member of our consortium (DeSaH). It was concluded that separate treatment of domestic wastewater fractions improves the overall resource efficiency of domestic wastewater treatment (Zeeman and Kujawa-Roeleveld, 2010). Therefore, the project will be scaled up to 200 households in 2012. Additionally, a recent study shows high acceptance, satisfaction of users of separation toilets and possible products recovered from urine (Lienert and Larsen, 2009).