The alkaline slurry leaving the red mud pond gets settled through a multistage, cascade type settling system resulting the separation of the suspended solids. The settling ponds are provided with permeable barriers that filter the red mud. The filtered, clear water is not yet neutralised at this stage, its pH still exceeds 12. This alkaline water is channelled in ditches around the red mud storage pond and before discharge into the Torna creek it is neutralised.
The photo shows the water collection ditches and next to them the red mud flooded area.