A water treatment plant treats 6000 m³ of water per day. As a part of the treatment process, discrete particles are required to be settled in a clarifier. A column test indicates that an overflow rate of 1.5 m per hour would produce the desired removal of particles through settling in the clarifier having a depth of 3.0 m. The volume of the required clarifier, (in m³, round off to 1 decimal place) would be

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.

The base of a river in in contact with the top of an aquifer. A truck carrying bags of powdered cyanide is on a bridge crossing the river when a large bump causes one of the bags to fall into the river. The water in the river suddenly becomes polluted by the cyanide with a concentrations of 6.78 mg/L. The aquifer has an average linear ground water velocity of 0.256 m/day. Laboratory analyses data indicates that longitudinal dispersivity can be found through the equation: a = 0.86(log Ls)² where Ls is the length of the straight line path between two points along the path of transport. Find the longitudinal dispersion 108 m downstream from the bridge. Assume that the cyanide solute has a diffusion coefficient of 3.6 x 10 -5 m²/s and the aquifer has a coefficient related to tortuosity (o) equal to 0.8. Find the coefficient of hydrodynamic dispersion.

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.