In this article we will discuss about the determination of sludge volume.
If Ww be the weight of the water in the sludge, W8 be the weight of the dry solids, ps be the specific gravity of the dry solids and p be the specific gravity of the sludge, mathematical the specific gravity of the sludge can be expressed as,
For all practical purposes, the specific gravity of the sludge can be taken equal to that of water, i.e. 1.0 then the sludge volume can be expressed as,
Where V =Volume of the sludge (wet)
V1 = Volume of the sludge (dry or semi-dry)
P = Percentage of water in the sludge (wet)
P1 = Percentage of water in the sludge (dry or semi-dry)
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Example 1:
Sludge is collected from primary settling tank. Its volume was 14 cu.m at moisture content of 95%. If after exposing it to the atmosphere, its water content reduces to 80%, determine its volume.
Solution:
The volume of the sludge at changed water content can be determined by the formula (18.2).
Example 2:
Design a sludge digestion tank with the following data:
(i) Average flow of sewage = 60 × 106 litres/day
(ii) Total suspended solids in the raw sewage = 350 mg/litre
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(iii) Volatile suspended solids = 250 mg/litre
(iv) Moisture content of the digested sludge = 87% Assume data not given suitably.
Solution:
Assuming that 65% removal is done in the primary setting tank and the fresh sludge has water contents of 95%.
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Volume of sludge collected in the primary setting tank.
Example 3:
Determine the volatile matter reduction in percentage with the following data:
Solution:
Considering 100 gm of total sludge in each case:
Example 4:
Design an oxidation pond based on the following data:
Solution:
