Florida Wastewater Practice Test

If you observe dark foam, high MLSS, and slow settling sludge with clear effluent, what action should you take?

1. Increase chemical dosage immediately

2. Decrease the aeration time

3. Maintain a 1-3ft sludge blanket and monitor MLSS

4. Remove the sludge entirely

The correct answer is: Maintain a 1-3ft sludge blanket and monitor MLSS

The correct approach in this scenario is to maintain a 1-3ft sludge blanket and monitor MLSS. Observing dark foam, high mixed liquor suspended solids (MLSS), and slow settling sludge suggests that the system may be experiencing issues related to the biological activity within the treatment process. By maintaining a proper sludge blanket, you allow for optimal conditions where the beneficial microorganisms can settle and digest the organic material effectively. Additionally, keeping an eye on the MLSS levels helps in determining whether adjustments are needed over time to optimize treatment efficiency without disrupting the biological processes too much. The presence of clear effluent indicates that despite the challenges with foam and sludge settling, the treatment system is still producing effluent that meets clarity standards. This suggests that while adjustments may be needed, the system has not yet deteriorated to a point necessitating drastic actions. Therefore, focusing on the stability of the sludge blanket and monitoring MLSS is crucial for maintaining effective operation and eventually resolving the issue without overreacting.