Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water fit for specific purposes. Most water is purified and disinfected for human consumption (drinking water), but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filtersor biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light. Water purification may reduce the concentration of particulate matter including suspended particles, parasites, bacteria, algae, viruses, and fungi as well as reduce the concentration of a range of dissolved and particulate matter.
The full form of TDS is 'Total Dissolved Solids'. The meaning of TDS in water is that it is a measure of how much chemicals there is in water. TDS is a technical term used to give a measure of the amount of dissolved matter in the water. TDS is usually expressed as 'ppm' which stands for 'parts per million' or as 'milligrams per liter' (mg/L). For convenience, usually the electrical conductivity of the water is measured and converted by using a multiplication factor to give an approximation of the TDS in water.
The World Health Organization (WHO) and most of the governments around the world has set an upper limit for the TDS - Total Dissolved Solids of non-toxic salts in water to 500 ppm (parts per million) or 500 milligrams per liter of water. Most of our Public supplied water is safe with regards to TDS, but it is a good idea to check.
Ultrafiltration is one of those water purification techniques that separates impurities/substances from the water to make it safe. The filtration process removes bacteria and other micro-organisms so that you get safe drinking water. UF water purifiers come with hollow fibre membrane material that feeds the water flow. The water enters either inside the shell, or it passes through the membrane (depending on the construction). The membrane retains suspended solid particulates and impurities of high molecular weight gets. The pure water which is free of contaminants passes through the membrane. UF is ideal for removing impurities such as colloids, bacteria, and macro molecules that are larger than the pore size of the membrane. The best part is the filtration process doesn’t use chemicals or electricity to purify water. Besides, it can remove 90-100% of pathogens from water and make it safe for drinking.
Ultraviolet water purification technique is another effective method of purifying the water. The process disinfects bacteria from water and makes it perfect for drinking. The water purifiers come with a high power UV lamp that kill harmful pathogens from the water. In addition, UV rays also eliminate the ability of the micro-organisms to reproduce. As a result, you are completely safe from illnesses and water-borne diseases caused by micro-organisms. The process is very much effective and environmentally safe. It destroys 99.99% of harmful microorganisms from water and makes it 100% pure and safe for consumption. During the purification process no chemicals are added and this is other added advantage of UV water purification techniques.
Carbon removes contaminants by chemically bonding to the water that is poured into the system. Some are only effective at removing chlorine, which only improves taste and odor, while others remove more harmful contaminants, such as mercury and lead. It is important to note that carbon filters do not have the ability to remove inorganic pollutants such as nitrates, fluoride, and arsenic. Carbon filters are usually sold in block or granulated form to consumers.
In general, MF, with its larger pore–sized membrane, allows water, monovalent and multivalent ions, and viruses through its barrier while blocking certain bacteria and suspended solids. Microfiltration can also be used to harvest cells from fermentation broth, and, as mentioned above, pre-treat water for RO.
Ion exchange technology uses a resin to replace harmful ions with ones that are less harmful. Ion exchange is often used to soften water since it has the ability to replace calcium and magnesium with sodium. In order for these filters to work for extended periods of time, the resin must be regularly “recharged” with harmless replacement ions. Ion exchange in your water in order to remove salts and other electrically charged ions. If a contaminant lacks an electrical charge, it will be removed by these filters. Living organisms, such as viruses and bacteria will not be removed by these filters.