What is used to coat the walls of sedimentation basins to rid the basin of slime growth?

• A. sodium carbonate peroxyhydrate
• B. dimethylalkylamine and lime
• C. copper sulfate and lime
• D. zinc pentahydrate

Answer: (C)

Coating the sedimentation basin walls with a copper-containing compound provides a targeted defense against slime by releasing copper ions that deter algae and biofilm-forming organisms on the surface. The lime included helps the coating adhere to the concrete walls and raises pH to optimize copper’s effectiveness while reducing corrosion. This creates a durable film on the walls that suppresses slime growth, helping keep the basin clear and improving settling performance. The other substances aren’t used for this purpose: they aren’t standard wall coatings for slime control in basins, whereas the copper sulfate and lime combination is the classic approach to deter slime on the basin walls.