Biological Waste Water Treatment Process

ANSWER 1:

BOD value importance Figure: BOD curve

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• For designing the biological waste water treatment process and design BOD values are of paramount importance as they are helpful in calculating the influent and effluent load requirement’s.

• The index for organic matter can be determined by the BOD values which will give an idea about the complexity of the organic pollutants present and the time requirements for its treatment, removal and other parameters.

• BOD values will give an idea of the duration required for the discharged waste water into a stream to be completely assimilated and treated naturally in the stream.

• It is the best qualitative test for

Removal of grit from the waste water is of importance for the treatment process reliability. Even though they are dimensionally smaller they cause several problems during the operation like – blockage, abrasion or damage to the pumps and other equipments, form a large part of the waste solids and take lasrge space in the digesters and because of their size they cannot be easily removed from equipments such as digesters or taks in which sedimentation is being carried out and interfere with the process of digestion creating odour.

The major constituents of Grit are solids that are having a greater specific gravity than that of the organic solids – sands, cinder, gravel and minor constituents include coffee grounds, large food particles, seeds, egg shells, chips of bones, etc. grit constituents are in one way inert to the treatment process. The specific gravity is approximately 2.65 and dimensionally equal to or greater than 0.011 inch. Some treatment plants will require the removal of particles having the dimesnisions equal to or greater than 0.007 in. this procedure is economically favourable than other other stages of the treatment.