Structural Analysis
6th Edition
ISBN: 9781337630931
Author: KASSIMALI, Aslam.
Publisher: Cengage,
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Transcribed Image Text:An aeration basin for an activated sludge facility has the following characteristics
Length = 90 ft
Width = 30 ft
Liquid depth = 12 ft
MLSS=4,000 mg/L
The raw wastewater has the following characteristics:
Flow = 12 MGD
BOD, = 220 mg/L
Suspended solids (SS) = 250 mg/L
A primary clarifier is ovided that removes 25% of the BOD, an 60% of the suspended solids The return activated-sludge flow rate is 0.8 MGD
If the primary sludge solids content is 4% solids and the specific gravity is 1.0, the primary sludge volume (ft³/day) is most nearly
OA. 1,500
OB. 60,000
O C.600
O D.4,500
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- A continuous stirred tank reactor (CSTR) Activated Sludge Process is used to treat municipal wastewater after primary sedimentation. The following data is available: Primary Effluent Flow Rate (Q) Primary Effluent BOD Concentration (So) Secondary Effluent Biomass Concentration (Xe) Mixed Liquor Biomass Concentration (X) Solids Retention Time (SRT) Waste Sludge Flow Rate (Qw) Value 450 200 O 0 3,000 5 8 Biomass Concentration in RAS (XR) 8,000 O 250 million gallons, 0.28 gBOD/gVSS.d, 13.3 hours 107 million gallons, 0.28 gBOD/gVSS.d, 5.7 hours O 107 million gallons, 0.42 gBOD/gVSS.d, 5.7 hours 107 million gallons, 0.28 gBOD/gVSS.d, 12.2 hour Unit mgd mg/l mg/1 mg/l days mgd The bioreactor volume (V), F/M ratio, and HRT are respectively: mg/larrow_forwardThe characteristics of the synthetic textile wastewater are 1500 mg/L BOD, 2000 mg/L SS, 30 mg/L nitrogen, and no phosphorus. The characteristics of the domestic wastewater are 200 mg/L BOD, 240 mg/L SS, 35 mg/L nitrogen, and 7 mg/L phosphorus. Find the nitrogen concentrations in the mixture. The ratio of flow rate is domestic/textile = 4/1arrow_forward2. The average wastewater flow from a community of 20,000 is 125 gpcd. The 5 day, 20 deg C BOD is 250 mg/L. The suspended solids content is 300 mg/L. A final plant effluent of 50 mg/L of BOD is to be achieved through the use of two sets of identical settling tanks and trickling filters operating in parallel. The settling tanks are to be designed to a standard of 1000 gpd/^2. The trickling filters are to be 6^ deep and operated at an organic loading of 55 lbm/1000^3 d. There is no recirculalon. (1) What settling tank surface area is required? In ft^2 (2) What settling tank diameter is required? In ft (3) Estimate the BOD removal in the settling tanks? In percent % (4) What is the trickling filter diameter? In ft domeved Wardarrow_forward
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