What problem is suggested by the presence of organic material in removed grit?

The presence of organic material in removed grit is indicative of several operational issues within a wastewater treatment system, particularly related to the grit removal process. When grit removal is functioning properly, it should effectively separate inorganic materials, such as sand and gravel, from the wastewater. If organic material is found in the grit, it often suggests that the flow velocities in the grit chamber are insufficient for proper sedimentation of heavier, inorganic particles.

Grit removal systems rely on specific hydraulic conditions to encourage the settling of grit while allowing lighter organic materials to remain in suspension and continue flowing with the wastewater. Adequate flow velocities contribute to the effectiveness of the separation process; if these velocities are too low, lighter organic particles might settle out along with the grit, which they should not be doing. This situation can compromise the efficiency of the overall treatment process and may require adjustments to the hydraulic design or operational settings of the grit removal system to improve performance.