- Wastewater leaving the activated sludge process is discharged into secondary clarifiers.
- There are 12 secondary clarifiers at the plant – four rectangular basins and eight round basins.
- The rectangular clarifiers have a total surface area of 2,500 m².
- Each of the round clarifiers has a diameter of 35 m with a surface area of 961 m².
- The total area of all of the plant’s secondary clarifiers is thus 10,190 m².
- Suspended particulates settle in these basins that primarily contain microbes active in the wastewater decomposition process.
- Some of these settled microbes are re-circulated into the activated sludge process in order to maintain a high microbe concentration there.
- The remainder of the settled material is added to the sludge from the primary settlement process and is transferred to the sludge treatment installations as will be detailed further on.
- The treated wastewater leaving the secondary clarifiers is termed effluent.
- Following treatment in the secondary clarifiers, the effluent is discharged into the operating reservoir of the Mekorot Water Company located next to the treatment plant. From there it is sent to the reservoirs operated by a farmers’ cooperative (Tishlovet Kishon) in the Jezreel Valley where it is used in irrigation for various crops.
Secondary settlement basins