In this article we will discuss about how to remove colour, odour and taste from water. Aeration: Aeration is a process in which water is brought in intimate contact with atmospheric air to promote exchange of gases between water and atmospheric air. The aeration of water serves the following purposes: (i) In the course of aeration, oxygen from atmospheric air [...]
Depending upon the stage of treatment at which chlorine is applied to water and also upon the expected results of application of chlorine; chlorination may be of the following forms: Form # 1. Plain Chlorination (or Simple Chlorination): Plain chlorination (or simple chlorination) indicates that only chlorine treatment and no other treatment is given to raw water, and after giving [...]
Learn about the comparison between lime-soda and zeolite process for water softening. Comparison # Lime-Soda Process: 1. Size of Plant: Bulky and large. 2. Supervision Required: Skilled supervision is required for successful working. 3. Sludge Problem if any: Large quantity of sludge is formed which needs to be disposed off by some suitable method. 4. Post Treatment if Needed: Recarbonation [...]
The following are the minor methods of disinfection: Method # 1. Boiling: The bacteria present in water can be killed by boiling it for a long time. This is the most effective method of disinfection of water. However, this method cannot be used to disinfect water on a large scale for public water supplies, for economical reasons. Moreover, it can [...]
Filters are classified on the basis of: (1) The filtration rate; and (2) The driving force to overcome the frictional resistance encountered by the water flowing through filler. On the basis of filtration rate the filters are classified as: (i) Slow sand filters; and (ii) Rapid sand filters. The Rapid sand filters arc further classified as: (a) Rapid gravity filters; [...]
In chlorination method of disinfection chlorine (or its compounds) is used as disinfectant. Chlorine is an element, having the symbol CI with an atomic weight of 35.45, melting point -101.5°C and boiling point 34.5°C. Gaseous chlorine is greenish yellow in colour and is approximately 2.5 times heavier than air. Under pressure, it is a liquid with an amber colour and [...]
A rapid sand filter (gravity type) consists of the following parts: 1. Enclosure Tank: It is an open watertight rectangular tank constructed of stone or brick masonry or concrete. The depth of the tank is about 2.5 to 3.5 m. The surface area of the tank may vary from 10 to 50 m2. Thus depending on the total surface area [...]
Permanent hardness of water can be removed by the following methods: Method # 1. Lime-Soda Process: In this method lime [Ca(OH)2] and sodium carbonate [Na2CO3] (or soda ash) are used to remove permanent hardness from water. The chemical reactions involved in this process are as follows: The compounds calcium carbonate CaCO3 and magnesium hydroxide Mg(OH)2 are insoluble in water and [...]
Following solved example will clearly illustrate the method of designing the water treatment plant: Example: A water works has to supply the water to a city having population of 5.3 lakhs the average per capita demand of the town is 145 litres/day. If the maximum demand is 1.5 times the average demand, design the complete water treatment plants from the [...]
In this article we will discuss about the location and layout of water treatment plant. Location of Water Treatment Plants: The water treatment plants should be located as near to the towns as possible. If the source of water supply is tube-well the treatment plant should be located in the central part of the town, so that purified water may [...]