The raw water from the SGRC flows by gravity through a 600 mm steel pipe to the FMC equipped with 25 Hp Rapid Mixer to ensure vigorous homogeneous mixing of the raw water with the chemical reagents. Attached to the 600 mm steel pipe are the upstream and downstream sensors of Plant Influent Digital Flow Meter to monitor the Rate of Flow of raw water and the data is transmitted to the OIT. Pre-chlorination is applied at the FMC to disinfect the raw water. Liquefied Aluminum Sulfate or Alum is also introduced at the FMC to allow flocs to coagulate and depending on raw water quality; polymer and soda ash are mixed in the same chamber. Polymer is used to augment coagulation of flocs while soda ash is added to correct the pH value. A float switch is installed to shut off the 25 Hp Rapid Mixer when raw water at FMC is at a certain low level.