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04000CE402052001

PART (^

Answer any two full questions, each carries 20 marks.
Design the dimensions of a septic tank for a small colony of 150 persons
provided with an assured water supply at a rate of 120 litres per person per day.
Assume any other data if required.
Discuss any two types of sludge disposal
Explain the features of an Imhoff tank with neat sketch
An oxidation pond is to be constructed in a hot climatic area for treating the
sewage from a residential colony with 5000 persons contributing sewage at 120
litres/capita/day. The 5day BOD of sewage is 300mg/ litre. Assume organic
loading in the pond as 300kg/ hectares/day. Calculate the dimensions required
for the tank and its detention time.
Write notes on sludge thickening?
Explain the features of a sludge digestion tank with a neat sketch.
List and explain the factors affecting anaerobic digestion.
Explain oxidation ditch with a neat sketch.
Calculate the area of land required for drying the sludge from the digestion tank
for 50,000 population, Also design the dimensions of beds. The dry sludge
content per capita per day is 0.068kg. The moisture of the sludge is 95%. The

specific gravity of wet sludge is 1.02.

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