# Impeller-powered Flocculation Basin

8.7 Step-wise solution to a numerical problem related to a flocculation-based water treatment plant having a flow of 25 MGD. The plant is to employ alum coagulation, and pertinent data for the flocculation basin are as follows: detention time = 20 min, G = 35 sec^-1 (at 50 degrees Fahrenheit), GT = 10,000 to 100,000, width = 1.25 times depth, length = twice width, no baffling, number of impellers = 2, number of blades per impeller = 6 pitched at 45 degrees, impeller diameter = 30 % of basin width, K_L = 70.0, and K_T = 1.65.

Determine:

(a) Basin dimensions if 1-in. increments are used.

(b) Impeller diameter

(c) Speed of impellers in rpm.

8.9 A lime-soda softening plant treats a flow of 150 MGD, and the water has 86 mg/l CO2. The commercial grade of quicklime has a purity of 85% and the soda ash has a purity of 95%. Determine:

(a) The pounds of quicklime and soda ash required per million gallons.

(b) The tons of quicklime and soda ash required per month if a month is considered to be 30 days.

https://brainmass.com/chemistry/environmental-chemistry/impeller-powered-flocculation-basin-571979

#### Solution Preview

I tried to solve it for you this time (attached), but once again these are hard core engineering problems. Chemists have nothing to do with reactor design! Please place your questions in appropriate category i.e. engineering.

[Once again these are hard core engineering problems. Chemists have nothing to do with reactor design! Please place your questions in ...

#### Solution Summary

The solution involves step by step calculations about an impeller-powered flocculation basin.