The sequence of processes in conventional surface water treatment plants is very regular. After large things such as fish and sticks have been screened out, coagulant chemicals are added to the water to induce the microscopic suspended particles that cause the water to become hazy to be attracted to each other and create “flocs.” Flocculation, or the production of larger flocs from smaller flocs, is usually accomplished by gently mixing the water over time to encourage particles and small floc to “bump” into each other, cling together, and form larger flocs.
The water goes into quiet sedimentation or settling basins after the flocs are large and heavy enough to settle. When the majority of the particles have settled out, filtration, either using sand or membranes, is usually used.
The following step is usually disinfection. Following disinfection, several chemicals may be added to correct pH, avoid distribution system corrosion, or prevent tooth decay. To remove inorganic or organic pollutants, ion exchange or activated carbon may be utilized at some point during the process. Groundwater is often of greater quality at the outset and requires less treatment than surface water.
Point-of-use and point-of-entry devices are often less complicated and utilise fewer technologies. Every consumer’s tap in most developed countries has pathogen-free drinking water that fulfills international standards.
As a precaution or to improve the visual features of the water in the public water system, a considerable number of consumers in the industrialized world choose to install point of use or point of entry devices. However, in many parts of the developing world, public water systems that offer pathogen-free water are unavailable, and success is judged solely by the reduction in the risk of diarrhea and other infections. As a result, a point-of-use system that is suitable for one place may not be suitable for another.
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