An activated sludge system using CSTR with sludge recycle has an influent flow rate (Q°) of 2.5 MGD that contains BOD of 200 mg/L. The volume of the aeration tank (CSTR) is 0.6 million gallons. The MLVSS (assume this is X,) in the aeration tank is 2000 mg VSS/L and the decay rate (b) is 0.1/day. The effluent from the secondary clarifier meets NPDES standards for suspended solids and BOD. The concentration of the settled sludge exiting the bottom of the secondary clarifier is 15,000 mg VSS/L. The sludge waste flow rate (Q") is 1 % of the influent flow rate, and the effluent flow rate (Q®) is ~99% of the influent flow rate. a) What is the hydraulic retention time, 0 (d)? b) What is the solids retention time, 0x (d)? Activated sludge with recycle c) What is the F/Ma ratio?

An activated sludge system using CSTR with sludge recycle has an influent flow rate (Q°) of 2.5 MGD that contains BOD of 200 mg/L. The volume of the aeration tank (CSTR) is 0.6 million gallons. The MLVSS (assume this is X,) in the aeration tank is 2000 mg VSS/L and the decay rate (b) is 0.1/day. The effluent from the secondary clarifier meets NPDES standards for suspended solids and BOD. The concentration of the settled sludge exiting the bottom of the secondary clarifier is 15,000 mg VSS/L. The sludge waste flow rate (Q") is 1 % of the influent flow rate, and the effluent flow rate (Q®) is ~99% of the influent flow rate. a) What is the hydraulic retention time, 0 (d)? b) What is the solids retention time, 0x (d)? Activated sludge with recycle c) What is the F/Ma ratio?

Structural Analysis

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ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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Integrated Solid Waste Management

Integrated Solid Waste Management (ISWM) is a thorough waste suppression, compost, removal and recycling Program. An effective ISWM system considers how to suppress, manage and recycle solid waste in a manner that is most efficiently to protect human health and the surrounding. ISWM system requires evaluation of public wants and demands and then selecting and merging the most effective waste management activities for the proposed demands. The main ISWM activities for solid waste management are Waste prevention, Recycling and Composting, and Combustion and Removal and waste collection in a properly planned, constructed, managed and mitigated landfill areas. Each of these requires careful designing, financing, accumulation, and delivery of activities.

Question

An activated sludge system using CSTR with sludge recycle has an influent flow rate (Q°) of
2.5 MGD that contains BOD of 200 mg/L. The volume of the aeration tank (CSTR) is 0.6 million gallons.
The MLVSS (assume this is X,) in the aeration tank is 2000 mg VSS/L and the decay rate (b) is 0.1/day.
The effluent from the secondary clarifier meets NPDES standards for suspended solids and BOD. The
concentration of the settled sludge exiting the bottom of the secondary clarifier is 15,000 mg VSS/L. The
sludge waste flow rate (Q") is 1 % of the influent flow rate, and the effluent flow rate (Qª) is ~99% of the
influent flow rate.
а)
What is the hydraulic retention time, 0 (d)?
b)
What is the solids retention time, 0x (d)?
Activated sludge with recycle
с)
What is the F/Ma ratio?

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