Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the concentration of such contaminants so the water becomes fit for its desired end-use. One such use is returning water that has been used back into the natural environment without adverse ecological impact.
The processes involved in treating water for drinking purpose may be solids separation using physical processes such as settling and filtration, and chemical processes such as disinfection and coagulation. Biological processes are also employed in the treatment of wastewater and these processes may include, for example, aerated lagoons, activated sludge or slow sand filters.
• Chemical addition → Flocculation and Coagulation
• Depth Filtration by a sand bed
• Relies on particle capture by gravity attraction as the carrier passes through the filter media
• Removal provides a nominal rating
• Surface filtration, potentially with chemical conditioning or cleaning
• Relies on rejection at the surface through a sileving or size exclusion
• Complete rejection provides an absolute rating
• Galvanic corrosion occurs when two dissimilar metals (copper and steel in the example below) are
connected and submersed in an electrolyte (water) whereby an electric charge is created, like a
DC battery. Negative electrons from the negatively charged metal (anode) will flow to the more
positively charged metal (cathode). Left alone, the charged metal will corrode away to nothing.