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Aerobic Digestion of Sludge | Print |

airBubblesPrior to dewatering, solids that are produced in treatment undergo a digestion process. Solids from the primary clarifiers, as well as waste activated sludge, are directed to the aerobic digesters via a splitter box. airNormally one basin is filling, while the other is in the digestion process, and its contents are being directed to the centrifuges for dewatering. Air provided by positive displacement blowers is added in high volumes to the two digesters to create aerobic conditions. Under these conditions, bacteria rapidly consume organic matter in the solids and convert it into carbon dioxide. Once the organic matter becomes limited, the bacteria die, become food for other bacteria, and the volume of sludge is reduced through this process of endogenous respiration.

The aerobic digester has covered tanks to prevent the release of odorous gases. Odorous air is withdrawn from these tanks and delivered to the odor control facilities for treatment. Continuous mixing is provided by air addition through coarse bubble diffusers. Digested sludge is pumped from the aerobic digesters up to the top level of the dewatering building to the centrifuges for dewatering.



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