06/12/2026
Cleaning day at WLSSD! 🧼
Wastewater and stormwater systems use sediment tanks (sometimes called settling basins, grit chambers, or sedimentation ponds) to allow sand, silt, gravel, organic material, and debris to settle to the bottom before the water moves on.
The sediment has to be cleaned out periodically because:
1. Maintains treatment capacity – As sediment builds up, there is less room for water. The tank can’t hold or treat as much flow during storms.
2. Prevents sediment from being carried downstream – If the tank fills with accumulated material, heavy rain events can stir it up and wash sediment into rivers, lakes, wetlands, or the next stage of treatment.
3. Protects equipment – Grit and sand are abrasive and can damage pumps, pipes, valves, and other equipment if allowed to move through the system.
4. Reduces pollutants – Sediment often contains pollutants such as phosphorus, nitrogen, oils, grease, heavy metals, road salt residue, and bacteria. Removing the sediment removes those contaminants from the water system.
5. Prevents odors and anaerobic conditions – Organic material trapped in the sediment can decompose, producing foul odors and potentially harmful gases if left too long.
6. Regulatory compliance – Many municipalities are required by state and federal permits to maintain stormwater treatment structures and document sediment removal to meet water quality standards.
