The existence of plenty of bacteria in the system means that oxygen is consumed, the oxidation reduction potential exhibits a negative value, and the entire system is anaerobic. Traditionally, a slime layer is generated in the stagnant part but with Kurita´s technology, the stagnation part disappears. The combination of Kurita’s patented biocontrol treatment, aeration technology and S.sensing^TM as monitoring system, leads to a lack of slime layer which increases the efficiency of the whole system. By using aeration with biocide, biocide acts effectively.