Narrative Report

The next, January 28, 2013 (Monday), we are scheduled to visit the MAYNILAD WATER TREATMENT PLANT. We arrived at 8:30 o’clock in the morning at MAYNILAD. But before we entered to the plant, all of us were registered to the guard’s log book and we make sure that we are wearing our hard hat for safety purposes. Then Engr. Bautista, (one of the staff of the plant) discussed us about the company profile, the processed and the equipment they used in treating the water. With this, we know that the MAYNILAD is owned by Metropolitan Waterworks and Sewerage System (MWSS). They are the services provider for the 17 cities and municipalities that comprise the West Zone of the greater Metro Manila area (540 square kilometers) and almost a million of consumers. They have two major source: The Angat Dam and the Laguna Lake. They get almost 97% of water from Angat dam. The plant consists of seven processes, namely, screening, coagulation/flocculation, sedimentation/clarification, filtration and disinfection. In screening, it removes large visible floating particles or sediments from water. Next, coagulation/flocculation, coagulants are mixed uniformly with water to be treated to make particles into flocs so that it can be easily to settle. La Mesa Treatment plant No. 1 is a conventional type and has a capacity of 1500MLD and the overload capacity 1600MLD while La Mesa Treatment plant No. 2 is a pulsator-type and has a capacity of 900MLD. The flocs are then made to settle down in sedimentation basin. Detention time is about two hours. After the sedimentation process, the water to be treated is passed through a media consisting of several layers of graded sand and anthracite charcoal to screen out all foreign particles which did not settle down in sedimentation basin. Maynilad use the chlorination method for disinfection purposes, having a dosage of only 0.3 – 1.5mgl of chlorine. Finally, the water sent to storage and ready for the distribution. Then, we have started the plant