What can correct the high solids concentration indicated by foam in an aeration tank?

The presence of foam in an aeration tank typically indicates a high concentration of solids, often due to excessive biomass or organic matter in the system. Increasing the wasting rate is an effective solution because it involves removing a portion of the mixed liquor (the combination of wastewater and activated sludge) from the aeration tank. By doing so, the overall solids concentration within the tank is reduced, which can help alleviate foam formation.

This practice effectively maintains a balanced microbial population and prevents the system from becoming overloaded, allowing for more efficient treatment of wastewater. A balanced population of microorganisms is essential for the successful breakdown of organic matter; hence, managing the wasting rate is a critical aspect of operational control in wastewater treatment systems.

Adjusting other parameters, such as aeration rates or flow rates, can affect treatment performance but may not directly address the issue of high solids concentration leading to excessive foaming. Adding more bacteria may temporarily increase biomass but could exacerbate the problem of solids concentration.