 Shit! That's the topic of my talk today. We can also put it more politely as waste water. Waste water is often regarded as something we need to get rid of, a smelly problem that we need to remove. But today I would like to convince you that your waste water is valuable. And on this circular journey we'll go through three steps. First, waste water. It's a resource. It contains nutrients such as phosphorus and phosphorus is very important for plant growth and for our food production. But the majority of phosphorus fertilizers are extracted and mined from phosphate rock reserves and these reserves are limited. And currently the world is running low on phosphorus. If we can supply sufficient phosphorus to a field, then we can't feed the world. But remember, waste water, it contains phosphorus. So we need to recover and reuse phosphorus, and that's exactly what I've been doing the past three years. This leads us on to the second step, phosphorus recovery. In my research I've been working with calcareous materials that are able to swerve and bind phosphorus. We can take advantage of this in our wastewater treatment by installing the material in a filter and letting wastewater pass by. When we do this, the material will capture and store phosphorus for later use. And we especially found one material that was very promising. And this leads us on to the third step, phosphorus reuse. We took the material from the filters and added it directly as a fertilizer to the plants. And we did see that the material was able to slowly release phosphorus for plant growth. Because as we added more and more material and more and more phosphorus, the plants responded with a higher biomass. So to sum up, one, wastewater is a resource. Two, we need to recover phosphorus from our wastewater. And three, we need to reuse this phosphorus. And we need to do this to close the phosphorus cycle. Thank you for your attention.