A rectangular settling basin has a depth of 3 m, a length of 40 m and a width of 6 m. The water treated in the basin has a flow rate of 500 L/s and contains 50 mg/L of type a particles, 100 mg/L of type b particles and 180 mg/L of type c particles (particle type letters refer to the particles listed in problem 1). What is the suspended solids concentration in the effluent from the settling basin? Determine the overall percent removal of suspended solids from the water achieved by the settling basin.

A waste sludge flow of 40 m³/day is gravity thickened in a circular tank with a diameter of 6.8 m. The solids concentration is increased from 4.5% to 7.5% with 85% suspended- solids capture. Calculate the solids loading in kg/m² d and the quantity of thickened sludge in m³/d.

Gave wrong values earlier. These are the correct values A settling tank having a depth of 3.5 m and surface area of 1000 m2 is used to remove particles of size 0.01 mm and specific gravity of 2.6. Calculate the removal percentage of the tank for the discharge of 7000 m3/d. Take viscosity of water as 1.1x10-3 kg/m.s.

A complete-mixed activated sludge process (CMAS) is to be designed to treat 6.0 MGD of primary effluent having a BOD5 of 190 mg/L. The requirement is that the effluent BOD5 and TSS concentrations be 20 mg/L or less on an annual average basis. The following biokinetic coefficient obtained at 15°C: Y = 0.6 mg VSS/mg BOD5, k = 2.85 d-1, Ks = 70 mg/L BOD5, and kd = 0.041 d-1. Assume that the MLVSS concentration in the aeration basin is maintained at 2,500 mg/L. Determine: a. The minimum MCRT (d) b. The MCRT necessary to meet the requirement (d) c. The volume of the aeration basin (ft3)