2. An activated sludge system is to treat wastewater from a population of 10,000 PE. The wastewater enters a primary clarifier with BOD5 of 300 mg/L and SS of 400 mg/L. The primary clarifier removes 30% of the BOD and 60% of the SS. A complete-mix reactor is to be used and from a pilot plant study, the Y and ka values are 0.5 kg/kg and 0.05 per day, respectively. Assume an MLSS concentration of 3,000 mg/L, a mean cell residence time of 10 days and underflow concentration from secondary clarifier of 9,300 mg/L. The effluent of the treatment system should comply with the Standard A of EQSR 2009. Determine the following: (a) The concentration of BOD and SS in the effluent of primary clarifier. (b) The dimensions of the aeration tank. Provide two rectangular tanks. Use width-to- length ratio of 1:2 and water depth of 4 m. (c) The food to microorganism ratio. (d) The recycle ratio.

2. An activated sludge system is to treat wastewater from a population of 10,000 PE. The wastewater enters a primary clarifier with BOD5 of 300 mg/L and SS of 400 mg/L. The primary clarifier removes 30% of the BOD and 60% of the SS. A complete-mix reactor is to be used and from a pilot plant study, the Y and ka values are 0.5 kg/kg and 0.05 per day, respectively. Assume an MLSS concentration of 3,000 mg/L, a mean cell residence time of 10 days and underflow concentration from secondary clarifier of 9,300 mg/L. The effluent of the treatment system should comply with the Standard A of EQSR 2009. Determine the following: (a) The concentration of BOD and SS in the effluent of primary clarifier. (b) The dimensions of the aeration tank. Provide two rectangular tanks. Use width-to- length ratio of 1:2 and water depth of 4 m. (c) The food to microorganism ratio. (d) The recycle ratio.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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