Texas Wastewater Class B Practice Exam 2025 - Free Wastewater Class B Practice Questions and Study Guide

When surface scum is not adequately managed in a clarifier, it can lead to decreased solid removal efficiency. Scum is typically made up of fats, oils, greases, and some solids that float on the surface of the wastewater. If not properly removed, this accumulated scum can impede the settling process of the solids in the clarifier, resulting in an increase in the total suspended solids (TSS) in the effluent. This can compromise the overall treatment process and reduce the effectiveness of the clarifier in separating solids from the treated water, leading to poorer quality effluent and potentially violating discharge permit limits.

The other outcomes associated with improper management of surface scum, such as improved aeration efficiency or enhanced nutrient removal, are not accurate. In fact, the presence of excessive scum can actually disrupt aeration processes and adversely affect the biological treatment efficiency. Furthermore, scum can hinder nutrient removal by altering the dynamics of the treatment processes needed for effective nutrient uptake by microorganisms. Therefore, managing surface scum is crucial for maintaining the operational efficiency of a clarifier in wastewater treatment.