1. Rectangular clarifiers have an overall cost advantage over circular clarifiers.   • Less overall construction costs:   Minimizes concrete with common wall construction.   Light-weight, easy to install equipment.   Rectangular design maximizes use of land space, minimizing   excavation.   • Lower equipment costs.   • Lower operational costs: Rectangular clarifiers typically require 1/2 HP motors, while circular clarifiers typically require 3 HP motors.   • Lower maintenance costs: Lightweight material requires less man power for maintenance and replacement. 2. Rectangular clarifiers are ideal for situations where maximizing use of land is a priority. Rectangular clarifier design utilizes continuous flow and common wall designs. 3. Unlike most rectangular tanks, the water in circular tanks is pumped in creating currents which significantly increase the settling time of suspended solids. 4. Circular tanks are susceptible to wind, which causes scum to collect on one side of the effluent weirs resulting in solids carryover. The Rectangular tanks are much less effected by the wind and have flights every ten feet that collect the sludge and move it forward to be removed.