A conventional activated-sludge plant treats 10.0 MGD of municipal wastewater with a BOD concentration of 240...

A conventional activated-sludge plant treats 10.0 MGD of municipal wastewater with a BOD concentration of 240 mg/l and suspended solids of 200 mg/l. The sludge flow pattern is shown in Figure 11-1 of the textbook with a gravity belt thickener to concentrate the excess activated sludge. Primary and thickened activated sludge are pumped separately to the anaerobic digester. The primary clarifier removes 50% of the suspended solids and 35% of the BOD. The primary sludge solids content is 4.0%. The operating F/M ratio for the activated-sludge process is 0.3 lb BOD per day per pound of MLSS. The solids content of the waste sludge removed from the secondary clarifier is 16,000 mg/l; the gravity belt thickening captures 95% of the solids in the sludge and increases the solids content of the thickened sludge to 7%. Calculate: a) Flow rate of primary sludge, in gals/day b) Flow rate of thickened secondary sludge, gals/day. c) Flow rate and solids concentration of the blended sludge

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genius_generous answered 1 year ago

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