The Badboot in Antwerp is the largest floating swimming pool in the world. It's swimming pool has almost the size of an olympic pool. On the boat a constructed wetland is placed in a steel basin floating above the showers and locker rooms. The wetland treats the wastewater from the swimming pool filters, the restaurant, toilets and showers. The system was designed by Rietland in coöperation with Naturally Wallace Consulting and then built by Rietland. The first stage is a vertical flow FBA type wetland (Forced Bed Aeration ®) and the second stage is a horizontal flow FBA system. Both wetland cells are 90 m².