What should the concentration of MLVSS be maintained at in an activated sludge plant with the given conditions?

In an activated sludge plant, the concentration of Mixed Liquor Volatile Suspended Solids (MLVSS) is crucial for the efficiency of the biological treatment process. MLVSS represents the portion of the total suspended solids in the mixed liquor that consists of viable microorganisms, primarily bacteria, responsible for breaking down organic matter in wastewater.

Maintaining a concentration of 1,000 mg/L of MLVSS aligns with optimal operating conditions for many activated sludge systems. This concentration ensures that there are enough microorganisms present to effectively treat the wastewater while also promoting adequate settling in the secondary clarifier. When MLVSS is maintained at this level, there is a balance that supports effective biological activity without leading to excessive biomass growth, which could complicate the treatment process and potentially lead to operational issues such as poor settling and increased foaming.

In contrast, concentrations significantly lower than 1,000 mg/L may lead to insufficient microbial populations, resulting in inadequate treatment and potential permit violations. Conversely, excessively high concentrations could lead to complications like bulking or foaming, further disrupting treatment efficiency and operational stability. Therefore, targeting 1,000 mg/L MLVSS is essential for achieving effective treatment outcomes in typical activated sludge facilities.