Sand and grit is a common problem in most wastewater treatment facilities and often accumulates as a result of pipe infiltration/inflow. Since we cannot see the accumulated material without draining the tank, the problem often goes unnoticed. This can greatly increase energy costs while reducing the treatment efficiency of the wastewater system. The energy costs can be significantly increased when diffusers are partially or completely covered by sand.
How can you tell — without seeing the accumulation of sand and grit on the bottom — that it is causing problems in your wastewater treatment system?
- Flow increases significantly following rainfall events.
- Higher energy costs — this is because the blowers or diffusers in your tanks need to run more to keep accumulated sand suspended so the bottom diffusers do not become covered and unusable, causing them to work overtime.
- System test results for BOD, TSS and Nitrates will worsen due to decreased treatment volume, which can mean lower quality effluent.
Removal of sand and grit is necessary for restoring capacity to wet infrastructures, improving treatment efficiency and reducing energy costs.
The following graphic illustrates how sand and grit go unnoticed: