Describe the various process involved in purification of water.

 The purification of water means making the unhealthy water potable. The purification of water involves following steps -

  1. Screening - The first step of purification of water is screening. In this step, the floating matter of large size present in the water is removed. Screening prevents the pumps and other equipments from the possible damage due to floating matter of sewage.
  2. Aeration - The process of exposing large surface of water to the atmospheric air is called aeration. After screening, water is collected in a large aeration tank and aerated by compressed air. This process removes volatile substances and gases like Hydrogen sulfide and carbon dioxide causing bad taste and odor. It increases the oxygen level in water. Due to aeration, precipitate of iron and magnese is formed which are separated from water.
  3. Sedimentation - The process by which suspended particles settle down under the action of gravity is known as sedimentation. Now, aerated water is placed in the sedimentation tank and stored for 10 - 14 days. It removes suspended particles to reduce the sediment load before treatment by other processes.
  4. Coagulation - It is chemical water treatment process used to remove solids from water, by manipulating electrostatic charges of particles suspended in water. Now, the water from sedimentation tank is placed in coagulation tank and ten some precipitating agents such as alum, lime etc., are added in water and mixed. These precipitating agents form precipitate of Aluminum hydroxide when dissolved in water. Suspended solids are absorbed on the surface of precipitate, so gradually mass of precipitate becomes heavier and finally settle down. This technique is used to remove very light suspended solids that do not settle by themselves during storage. The clean water above is transferred to a filtration tank with the help of a pump.
  5. Filtration - Water in the filtration tank has to pass through the levels of charcoal, pebbles and fine sand. There is a collection tank at the bottom of the filter bed to collect filtered water. This process removes approximately 99% of microorganisms and other impurities.
  6. Disinfection - Disinfection is generally done by chlorination. The application of chlorine to water for the purpose of disinfection is known as chlorination. Chlorine or bleaching powder is mixed with water in the tank. By doing this, harmful bacteria present in the water are destroyed and the water obtained thus is potable.

Above is the process of purification of water.

Comments

Post a Comment

Popular posts from this blog

What is PVC ? What are the advantages of it as a construction material ?

Image
  PVC - Polyvinyl chloride It is a vinyl polymer which structure is very much similar to polythene. It is produced by the free radial polymerization of vinyl chloride. In the recent years, the use of polyvinyl chloride has been increase in construction work due to their excellent property. It is resistance to fire, water, flame, and corrosion. It has light weight and great insulating property. As a building material, PVC is cheap and easy to assemble. It has become an alternative of conventional building materials like wood, concrete or clay. Advantages of PVC - Being a resistance to water, it is used to make shower curtains, water pipes etc. Being a hard plastics, it is used in window profiles, pipe, plumbing etc. It is extensively used in sewer industries for pipelines of the water. It is flexible. After addition of plasticizers, we can use it as roofing membranes and in electric cable insulation.  Thank you. Gracious! My Quora space My YouTube channel
Read more

Lug angle and tension splice - Introduction

Image
  Lug angle - Lug angle is an angle section of short length which connects the outstanding legs of angle section or member to the gusset plate.  It reduces the length of connection to the gusset plate and also reduces the shear lag effect.   When the lug angle is used, the unconnected length of main angle acts like a connected leg and hence entire cross-section area start resisting the tension. Thus, shear lag effect reduces and efficiency of the tension member increases.   Lug angle provides extra gauge line to accommodate the numbers of bolts.   Tension splice - Tension splice are the cover plates used on both sides of butt jointed members. A tension member is spliced when the length of section available is less than that of tension member required. when the members of different thickness are spliced, packing is required to fill the gap. The area of splices should be slightly more than that the member joined. It is also used when the size of the memb...
Read more

Difference between butt joint and lap joint

Image
  LAP JOINT - In this joint, two members are overlapped and connected together. The load in lap joint has eccentricity because centre of gravity of load in both members are not in same line. Thus, a couple is formed which causes undesirable bending in the connection and the rivets may fail in tension. Also due to the eccentricity, the stresses are distributed unevenly across the contact area between the rivets and members to be connected.   BUTT JOINT - In butt joint, both members are placed end to end and additional plate/plates (cover plate) is provided on either one side or both sides and connected to the main plates. When one cover is provided, it is called single cover riveted butt joint and when double cover is provided,it is called double cover riveted butt joint.   It was the difference between lap and butt joint. Now, we will know superiority of butt joint. Butt joint is superior than lap joint because 1. In the case of a double cover butt joint, eccentricity of ...
Read more