Water purification

Water purification

• Water purification is the removal of contaminants from raw water to produce drinking water that is pure enough for human consumption or for industrial use
• Substances that are removed during the process include parasites (such as Giardia or Cryptosporidium) , bacteria, algae, viruses, fungi, minerals (including toxic metals such as Lead, Copper etc.), and man-made chemical pollutants.
• Many contaminants can be dangerous—but depending on the quality standards, others are removed to improve the water’s smell, taste, and appearance.
• A small amount of disinfectant is usually intentionally left in the water at the end of the treatment process to reduce the risk of re-contamination in the distribution system.
• Many environmental and cost considerations affect the location and design of water purification plants.
• Groundwater is cheaper to treat, but aquifers usually have limited output and can take thousands of years to recharge.
• Surface water sources should be carefully monitored for the presence of unusual types or levels of microbial/disease causing contaminants.
• The treatment plant itself must be kept secure from vandalism and terrorism.
• It is not possible to tell whether water is safe to drink just by looking at it.
• Even natural spring water – considered safe for all practical purposes in the 1800s – must now be tested before determining what kind of treatment is needed.