Clarifier clarity

摘要

A chemical production facility in the Midwestern U.S. was troubled by excessive solids in its wastewater effluent. During periods of high organic loadings, denitrification would occur in the secondary clarifiers, creating nitrogen gas bubbles that carried solids to the surface. Similarly, during periods of varying hydraulic conditions, entrained gases would be carried into the quiescent zones of the clarifiers, also causing solids to float to the surface. Ultimately, the solids would escape over the weirs of the secondary clarifiers, elevating the solids concentrations in the facility's effluent.