rimary and secondary) per day. Assume 30% removal efficiency of the primary clarifier and F/M ratio of 0.2 for the aeration tank. Determine the following: a. Primary sludge volume and removal efficiency of primary clarifier b. Influent and effluent BOD5 of the secondary activated-sludge system c. Volume of secondary sludge with 1% solids content. b) In problem a), the primary and secondary sludges are mixed in a gravity thickener and sent for further treatment. The thickened sludge contains 4% solids. Calculate the percent volume reduction in the gravity thickener. c) The thickened sludge from problem b) is to be digested in a standard-rate mesophilic anaerobic digester (MAD). The sludge has 68% organic content, and ap
a) A wastewater treatment plant consists of primary treatment followed by an activated-sludge secondary system. The plant processes 7000 m3/d of wastewater with 180 mg/L of BOD5 and 150 mg/L of suspended solids. The primary sludge contains 500 kg of dry solids per day with 4.5% solids content. The plant produces 760 kg of total sludge (primary and secondary) per day. Assume 30% removal efficiency of the primary clarifier and F/M ratio of 0.2 for the aeration tank. Determine the following: a. Primary sludge volume and removal efficiency of primary clarifier b. Influent and effluent BOD5 of the secondary activated-sludge system c. Volume of secondary sludge with 1% solids content.
b) In problem a), the primary and secondary sludges are mixed in a gravity thickener and sent for further treatment. The thickened sludge contains 4% solids. Calculate the percent volume reduction in the gravity thickener.
c) The thickened sludge from problem b) is to be digested in a standard-rate mesophilic anaerobic digester (MAD). The sludge has 68% organic content, and approximately 60% of the organic fraction is digested after a 30-d period. The digested sludge has a solids content of 6% and is stored for a period of 90 d. Calculate the volume of the standard-rate digeste
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