The backwash wastewater flow by gravity into the sludge pit and as the water reaches the set water level, the 2-30 Hp Submersible Sludge Pumps automatically run and empty the sludge pit by transferring its content to the sludge lagoon.

Backwashing can be performed in three (3) ways; Automatic, Semi-automatic and Manual. In Automatic mode, any 1 of the 3 abovementioned parameters based on predetermined set-points can start the Filter Backwash Process without human intervention. In Semi-automatic mode, only the Start Backwash Switch needs to be pressed and the Backwash sequence shall commence. While in the Manual mode, the WTP Operator takes the control and handles the Filter Backwash Sequence.