The first time we visited Ülemiste water cleaning station, was on the fourth of October. That time was just like an excursion. We went there, just to learn facts and see how the water station works. We listened to our contact person at the water cleaning station, she told us how the water is cleaned in the station, and showed us around. The second time we went at the twelfth of the December, and this time, we got showed how the clarifiers are cleaned. Two workers had already washed the clarifier, but they showed us how they did it. They took a firefighter’s water hose, stood on the edge of the clarifier, and washed it. It would have taken about two or three hours to completely wash it. Also, we saw how an empty clarifier looks like.