Drain water purification through microalgae

Microalgae cultivation can be elegantly integrated in horticulture practice as a treatment method for discharged drain water. The drain water represents an ideal environment for the production of valuable microalgal biomass, while in return, the water is purified from its high nutrient loads. This synergy greatly improves the circularity of both systems and reduces costs for the cultivation of microalgae - a modern crop that has applications in food, fertilizer, pharmaceutical, and animal feed industries.


The nutrient solutions used in soilless farming contain high concentrations of nitrate and phosphate, ensuring the optimal growth of the plants. After some time, however, this solution needs to be discharged in the form of drain water, at which point the high nutrient load becomes a burden on the environment as it promotes the uncontrolled growth of microorganisms. 

Project REALM aims to take control over this process, by using the discharged drain water as a cultivation media for photosynthetic microalgae. 

Project description

In order to integrate this drain-water upcycling approach effectively in the Netherlands, we will test the growth of potential strains under seasonal climate conditions; we will maximize nutrient reclamation by optimizing for > 99% uptake efficiency; and we will explore the possibilities of an algal crop rotation sequence that allows for year-round production with continuous high productivity.