| WATER TREATMENT |
| Residents in Metro Manila need water for everyday life. That is why treatment is important to make it safe and acceptable for human use. Water companies use different strategies to treat water. That includes filtration, flocculation, sedimentation and disinfection. These are employed to remove color, turbidity, taste, odors and bacteria. SCREENING Water from rivers will flow to big screens to remove organism like fish, leaves and other materials. FLOCCULATION First mixing is employed. Mixing or rapid mixing is the process where the chemicals are quickly and uniformly dispersed in the water. Ideally, the chemicals would be instantaneously dispersed throughout the water. During coagulation and softening the chemical reactions that take place in rapid mixing form precipitates. Either aluminum hydroxide or iron hydroxide form during coagulation, while calcium carbonate and magnesium hydroxide form during softening. The preicipitates formed in these processes must be brought into contact with one another so that they can agglomerate and form larger particles called flocs. This contacting process is called flocculation and is accomplished by slow, gentle mixing. Rapid mixing is probably the most important physical operation affecting coagulant dose efficiency. Rapid mixing can be accomplished within a tank utilizing a vertical shaft mixer within a pipe using an in-line blender or in a pipe using a static mixer. Other methods such as Parshall flumes, hydraulic jumps baffled channels or air mixing may also be used. SEDIMENTATION Particles that will settle within a reasonable period of time can be removed in a sedimentation basin or clarifier. Sedimentation basins are usually rectangular or circular witheither a radial or upward water flow pattern. Regardless of the type of basin, the design can be divided in four zones: inlet, settling, outlet, and the sludge storage. Next....... back to My Research |