There is a clear increase in the number of projects where waste water is no longer considered as a waste product, but as a source of raw materials. The recovery of energy and nutrients plays a central role in this.
A good example of one of these projects is the decentralised water treatment plant in the Dutch government building Nieuwe Rijkskantoor at Rijnstraat 8 in The Hague. The new accommodation for approx. 6000 civil servants from a number of government ministries are equipped with an installation that processes the waste water and recovers energy and nutrients from it.
In short, this means that the existing residual flows from the office are treated in the building itself. For example, the black water from vacuum toilets is collected together with the organic waste in a concentrated manner and processed in a digester. The digestion process produces renewable energy in the form of biogas that is used to heat the building. The yellow water from the urinals is processed in the struvite reactor. Phosphate is recovered from the collected urine in the form of struvite. This can be applied directly as fertilizer. Because waterless urinals and vacuum toilets are used, considerable savings are made on the consumption of drinking water.
DeSaH designed and built the installation. This new installation will pay for itself through savings on water use, water treatment levy and costs of waste treatment and energy. The Ministry building is the largest office where such a sustainable sanitation concept has been applied.