Controlled struvite production at Houtrust WWTP

Wastewater Treatment, Nutrient Factory

This research has the aim to investigate the possibility to implement controlled struvite production at the Houtrust WWTP. Struvite is a crystalline phosphorus salt, formed from the precipitation of phosphorus with magnesium and ammonium. Digested sludge with high free phosphate concentrations has relative poor dewatering characteristics. When this phosphate under controlled conditions is removed by addition of magnesium, a higher dry matter content of the sludge cake can be obtained and less dewatering polymer is needed. In addition potential uncontrolled struvite scaling can be reduced which can be a problem in some cases. Phosphate present as struvite in the sludge cake is disposed to sludge incineration (HVC) and as foreseen recycled from the ash by Ecophos.
Multiple factors are taken into consideration, for example; sustainability, costs, feasibility, transport etcetera. A major factor is the environmental impact, when a struvite reactor is used, there is a cutback in the use of Iron salts, therefore decreasing the environmental footprint even further. The results from this research are important for the determination if controlled struvite production will be implemented at the Houtrust WWTP.

Start of Research
November 2016

End of Research
April 2017

- Daan Boswinkel
- Marlies van Hoeve
- Paul Weij


- Delfluent Services BV
- Delfland Water Authority
- The Hague University of Applied Science


Daan Boswinkel
[email protected]