An integral part of flow equalization is mixing.

• A. Aeration
• B. Filtration
• C. Mixing
• D. Settling

Answer: (C)

Flow equalization aims to smooth out fluctuations in flow rate and pollutant load by storing excess inflow and releasing it at a controlled rate. To make that work, mixing inside the equalization basin is essential. Thorough mixing keeps the tank contents uniform in concentration, prevents pockets of high or low concentrations from forming, and stops solids from settling out or separating, so the blended flow reflects the average quality and quantity. This uniformity also helps downstream processes and chemical dosing operate consistently, since they’re fed with a well-mixed stream rather than pulses of concentrated material. Aeration adds oxygen, which isn’t the goal of equalization; filtration removes solids, and settling tends to separate solids from liquid—these are not about blending the contents to achieve a steady, uniform input.