In the rectangular flotation units, the quick mixing and stirring basin is installed in front of the flotation basin. Quick mixing can also be done with a static pipe mixer. Several models of sludge scrapers are available for different basin lengths. Chain scrapers, wagon scrapers and rotary horizontal blade/spiral scrapers are used for surface sludge. Chain scrapers, wagon scrapers and pneumatically operated blade scrapers moving back and forth are used for bottom sludge. The flow inside the basin is also used for the scraping of bottom sludge, leading the sludge into the bottom sludge suction piping.

Dispersion water is prepared like in our other flotation unit models. Dispersion water is fed through nozzle piping into the infeed and mixing space located between the stirring basin and the flotation basin. The water for the preparation of dispersion water is taken from the end of the flotation process where the cleanest water is available, or from a purified water basin placed after the flotation process.