What should be done if foam appears in the supernatant of a single stage tank due to organic overload?

When foam appears in the supernatant of a single-stage tank due to organic overload, reducing the feeding rate is the appropriate response. This foam formation is typically a sign that the system is being overloaded with organic material, leading to excessive biomass growth or instability in the treatment process. By decreasing the feeding rate, you allow the system to stabilize and provide the microorganisms with the appropriate conditions to effectively break down the organic matter without becoming overwhelmed.

Lowering the inflow of organic material helps to mitigate the symptoms of overload, which include foam formation, poor settling, and potentially decreased treatment efficiency. It is essential to maintain a balanced hydraulic and organic loading in wastewater treatment processes to ensure that the biological treatment can effectively perform its function.

Increasing the feeding rate would exacerbate the problem, thickening the sludge might not address the foam issue directly, and reducing aeration could compromise the oxygen levels needed for aerobic microorganisms, further destabilizing the treatment process. Thus, reducing the feeding rate is crucial to improving the overall effectiveness of the treatment system.