Separating Out Urine Makes For Highly Efficient Waste Water Treatment

The basic idea is simple: urine accounts for only 1% of the total volume of wastewater, but it contains up to 80% of all the nutrients. If it is processed separately, wastewater treatment plants can be reduced in size, water protection can be improved, and nutrients can be recycled. Separate treatment of wastewater streams thus opens up new possibilities, and there are many reasons for adopting urine source separation (“NoMix”) technology on a large scale.

This is particularly important in fast developing countries such as China, where sewerage and wastewater treatment facilities cannot keep up with the rapid pace of urbanization, and water pollution arising from domestic wastewater has reached devastating levels.

While the Eawag researchers’ approach may sound straightforward, there is no guarantee that it can be implemented in practice: infrastructure that is already in place cannot be transformed overnight; the new toilets still have some defects – pipes may be blocked by urine scale; the sanitary industry as yet sees little commercial potential in the NoMix technology, and the fertilizer produced from urine cannot yet compete with low-cost artificial products. So obstacles remain to be overcome. 

if urine is to be treated with the aid of decentralized systems, and nutrients are to recovered in a concentrated form for recycling, what options offer the best prospects of implementation and the lowest environmental impact? For researchers Tove Larsen and Judit Lienert, it is quite clear: “It’s standard practice for garden waste to be separately collected. So surely it should also be possible one day for the six kilograms of concentrated phosphorus produced each year by a family of four to be separately processed.”