Water Treatment

 The process that enhances the quality of water to meet the water quality criteria for the desired use is known as water treatment. The desired use can be drinking water purposes, industrial processes and many other processes. Reducing the contaminants in water or to reduce the concentration of such contaminants is the main aim of all water treatment processes. There are many processes involved in treating water for drinking purposes. The processes include physical procedures like settling and filtration and chemical processes like disinfection and coagulation. Several biological processes like aerated lagoons, activated sludge or slow sand filters are also used in the treatment of water.

Potable water purification

The process of eliminating unwanted chemicals, materials and other contaminants from water is known as water purification. Water is normally purified for the purpose of drinking. The contaminants removed during the process of drinking water treatment include suspended solids, bacteria, algae, fungi, and minerals like iron and chemical pollutants. Several measures are espoused for quality water treatment. Measures taken for making sure water quality is associated with water treatment and conveyance and treatment after treatment. World Health Organization (WHO) has provided several guidelines that should be strictly followed by all water treatment plants. Each country or state or water supply body has the right to develop their own guidelines for safe treatment of drinking water.

Various Treatments

Several processes like pumping & containment, screening, storage, conditioning, chlorination, p^H adjustment, flocculation, sedimentation, filtration, disinfection are used in water treatment plants depending on the scale of plant. Screening, storage, chlorination and conditioning are some important pre- treatment methods available to remove the fine solids, micro organisms and dissolved organic and inorganic materials. If the water is acidic, then to raise the p^H lime, soda ash or NaOH has to be added. Forced draft degasifiers are the cheapest way to raise the p^H for acidic water. Flocculation is a process used to make water so clear by removing turbidity or color. Sedimentation is the method used for solid separation that means the removal of suspended solids trapped in the floc. Aeration helps to remove dissolved iron and manganese from water.  Filtration is the final step involved in water purification to remove any suspended particles or unsettled floc. Rapid sand filter is the most common type of filter used. Disinfection is the method of killing bacteria in water. All these technologies are well developed. To reduce waterborne diseases; almost all countries have implemented water treatment programs.

Questions:

• Define water treatment?
• What are the various water treatment methods?