The Sewage Treatment plant of Koholmen

Biological Handling - PrincipleThe main purification of the sewage water takes place in the biological handling steps. Differentnaturally occurring microorganisms, chiefly bacteria, which come in via the sewage water and thenmultiply in the bio tanks, carry out the purification. The microorganisms that take part in the purificationprocess are extremely specialized and have each different demands on the environment. Thereforeconditions are created in the bio tanks that best favour those bacteria cultures wanted. By pumpingback those bacteria that are separated further on in the process a very high concentration ofmicroorganisms is obtained in the bio basins. Thereby the work of the microorganisms will be carriedout in one place and with much higher speed than in natural systems.Different microorganisms carry out the purification. In the bio basins conditions are created thatfavour those bacteria cultures wanted. Illustration: Pär Samuelsson