Chapter 12, Problem 7P

Estimate the required air flow rate for the new activated sludge plant at Pea Ridge (Problems 23-223-723-10, and 23-13). The flow rate is 8,450 m³/day, the concentration of bCOD going into the system (So) is 137 mg/L, the concentration of bCOD leaving the system (S) is 16.3 mg/L, and the mass of cells produced per day (Pxvss) is 277.4 kg/d. Use the following assumptions to estimate the required air flow rate: . Clean water correction, a = 0.50 . Salinity correction, B = 0.95 Fouling factor = 0.9 Wastewater temperature = 12°C Atmospheric pressure = 101.325 kPa .Elevation 500 m . Depth of aerator = 5.6 m Operating DO 2.0 mg/L Percent oxygen leaving aeration tank - 19% ■ Manufacturer's SOTR = 535 kg/d Manufacturer's air flow rate at standard conditions 50 m³/d - aerator Express your answer with the units of m³/d and round to the nearest integer.

Determine the required solids retention time (SRT) of a completely mixed activated sludge aeration tank for a conventional activated sludge system treating a design flow rate of 34,560 m³/d, where the effluent standards are 30.0 mg/L for BODs and 30.0 mg/L for total suspended solids (TSS). Assume that the BOD5 of the effluent TSS is 70% of the TSS concentration. Assume the BODs concentration leaving the primary clarifier is 128 mg/L that the MLVSS concentration (X₂) is 2,500 mg/L. Assume the following values for the growth constants: Ks 100 mg/L BODS ⚫ Hm - 2.5 d 1 kd = 0.050 d 1 Y = 0.50 mg VSS/mg BODs removed Express your answer in days and round to the nearest 0.1.

Q1: Figure below shows loaded beam with its cross-section area, (A) Draw shear force and bending moment diagrams, stating the main values, (B) Find central slope and deflection, (C) Sketch the distribution of shear stress at left support, (D) Find maximum tensile and compressive bending stresses set up in beam at right support. E-205GN/m² P1 P2 P3 W1 W2 Lin Lin # A Length in (m) and loads in kN 3a a 2a 2a (Cross-section area, All dimensions in (mm))