What is the best-known solution for excessive algae growth in a presedimentation impoundment?

• A. Line the bottom
• B. Cover the impoundment
• C. Chlorinate to kill the algae
• D. Use potassium permanganate

Answer: (B)

Sunlight drives algae through photosynthesis, so limiting light is the most effective way to curb excessive growth in a presedimentation basin. Covering the impoundment blocks sunlight, slows or stops algae blooms, and helps keep the basin from becoming loaded with algae that can affect taste, odor, and sedimentation processes downstream.

Lining the bottom doesn’t reduce light exposure at the surface where algae grow. Chlorinating to kill algae introduces chemical handling, residuals, and potential taste/odor issues and isn’t as straightforward or practical for a large basin. Potassium permanganate is an oxidant used for other pretreatment purposes and isn’t the standard, most reliable method for preventing surface algae growth.