DIFFERENT STEPS OF WASTE WATER TREATMENT

AIM OF  WATER TREATMENT

• Mainly water pollution caused by industrial sewage  and domestic sewage .The term sullage is applied to waste water which are free from human excreta.The basic objective of treatment of waste water ,industrial or municipal water ,is to bring the quality of water to a permissible /allowable level as prescribed by environmental laws.

THE BASIC AIM OF SEWAGE WATER TREATMENT ARE 

• 1.Produce an effluent free from pathogens and that  can be dispose of without any rise of environmental and health problem
• 2.Remove the suspended particulate matter 
• 3.Removal of organic matter lode through decomposition by bacterial action into inorganic compounds .

PRIMARY TREATMENT OF WATER

• It include physical separation of suspended material by screening,flocculation,sedimentation,filtration and floatation.The water first treated with alum FeCl3 to precipitate suspended particle.

SECONDARY TREATMENT OF WATER

• It include biological process like -removal of biodegradable organic colloidal or dissolve biological method of removal of certain catagories of chemical compound in order to reduce the biochemical oxygen demand (BOD).Activated sludge process and trickling filter process are more important technique for secondary treatment of waste water.

TERTAIRY TREATMENT OF WATER

It involve  physical,chemical and biological process for the removal of the nitrogenous ,phosphatic and other inorganic pollutant -removal of color ,order and removal of the remaining organic pollutants.

PURIFICATION OF WATER 

• Water is called portable/acceptable for drinking ,when it free from pathogen and harmful chemical substances .Mainly water is available on three sources such as -rain water,surface water and ground water -contain impurities ,so it should be purified before use for drinking and domestic purposes and other purposes.

• In the large scale water is purified in three steps-such as -storage ,filtration and chlorination.

1.STORAGE

• We can store water in natural and artificial reservoir -it allow the suspended particle to settle down .When sunlight enters to water body it allow photosynthesis ,which leads to increase in oxygen level and water body and which help in reduction of Biochemical Oxygen Demand and it is helpful in natural purification of water.

2.FILTRATION

The filtration id done by biological or slow sand filtration and by the rapid sand or mechanical filter 

Supernatant and the raw water flow downward through the sand bed and during such perculation of water a number of purification process such as mechanical screening ,sedimentation ,absorption,oxidation and bacterial action takes place during filtration ,a biological layer develop in the sand containing algae and bacteria which remove organic matter.

CHLORINATION

• Chlorination is the addition of chlorine to waste water and a supplement to sand filtration kill pathogenic bacteria .chlorine also oxidises iron ,manganese and hydrogen sulfides ,destroy some odor producing constituents and control algae 

PURIFICATION OF WATER ON SMALL SCALE  

BOILING 

• Boiling of water kills all bacteria ,spores,cysts and ova.Also remove the temporary hardness of water by percipitating calcium carbonate .

CHEMICAL DISINFECTION

• The water can be disinfected with many chemical like iodine ,potassium Permanganate and chlorine .Chlorination of water can be done using bleaching powder .Iodine can be used for emergency disinfection.

FILTRATION

• Water also can be purified on small scale by filtering it through ceremic filter ,which are excessive use now-a-days .Filter candle of the fine type usually remove bacteria,but not virus.