Different Processes of Water Treatment
We need clean, safe water in everyday living. It is very important for the community's well-being, hygiene and productivity.
The process of treating water may slightly be different at various places, depending on the technology of the plant that needs processing. Nevertheless, the principles are basically the same. The following section will give you a description of the different standard water treatment processes.
Coagulation / Flocculation
During the process of coagulation, liquid aluminum sulfate or alum and/or polymer is mixed with raw or untreated water. The mixture causes the tiny dirt particles in the water to stick to one another or coagulate. Then, these dirt particles form groups that stick together and form flocs, larger heavier particles that can be removed easily by filtration or settling.
When the particles of water and flocs go through the treatment process, they flow into the sedimentation basins. Here the water runs slowly, letting the heavy floc particles settle to the bottom. Floc that accumulates on the bottom of the basin is known as sludge, which is channeled to drying lagoons. Direct Filtration does not include the sedimentation step, and filtration is the only process by which the floc is removed.
Water passes through a filter intended for removing particles in the water. The filters comprise layers of gravel and sand and, at times, crushed anthracite. Filtration gathers the suspended impurities in the water, then further enhances the efficiency of disinfection. The filters are cleaned on a regular basis thorough backwashing.
Before water moves into the distribution system, it is disinfected to make sure that disease-causing bacteria, parasites and viruses are destroyed. Chlorine is applied because it a great disinfectant, and the remaining concentrations can be maintained to protect from probable biological contamination in the distribution of water.
Solids collected then settled outside the water via filtration and sedimentation are piped to drying lagoons.
This is the treatment of community water aimed at adjusting free fluoride ion concentration to the optimum level enough to minimize dental caries. It is a requirement for Hunter Water to fluoridate water in compliance with the NSW Fluoridation of Public Water Supplies Act 1957.
Lime is mixed with filtered water in order to adjust the pH level and stabilize the naturally soft water so that corrosion in the distribution system plus the customers' plumbing will be reduced.
by Karina Popa