Sludge Digestion Tank
The decomposition of complex organic matters in sludge by the biochemical reaction created by anaerobic bacteria is termed as sludge digestion. The sludge can be digested by a sludge digestion tank or an Imhoff tank.
⇛ The sludge digestion tanks are generally circular in shape with a flat or hopper-shaped bottom. The tanks are usually covered at the top to retain heat and odours and for collecting the sludge gas.
⇛ The floor of the tank is given a slope of about 1:1 to 1:3. Fresh raw sludge is usually introduced within the middle third section of the tank.
⇛ For taking out sludge liquor, two or more outlets are provided at different levels. One outlet is provided at the bottom to collect the digested sludge for its disposal. In some tanks, scum breaker arms are provided which brake scum.
⇛ Most of the tanks are provided with stirring equipment for thorough mixing of the sludge.