Ontario Operator-in-Training (OIT) Practice Exam

When is comminution typically used within wastewater treatment?

1. Final treatment stage

2. Preliminary treatment

3. Pumping process

4. Filtration process

The correct answer is: Preliminary treatment

Comminution is typically employed during the preliminary treatment stage of wastewater treatment. This initial phase is crucial for preparing wastewater for subsequent treatment processes. Comminution involves the mechanical reduction of the size of solids present in the wastewater, which can include both particulate matter and larger debris. This step is important to ensure that these materials do not interfere with downstream processes, such as sedimentation or biological treatment, which can be negatively impacted by larger solids. By reducing the size of these solids, comminution facilitates better flow through treatment equipment, improves the efficiency of screening and other processes, and helps prevent potential blockages in pipelines, pumps, and filters. Hence, its application is critical at the beginning of the treatment process to optimize the overall treatment efficiency. In contrast, other stages such as final treatment, pumping, and filtration focus on different objectives within the wastewater treatment system, such as clarifying and purifying treated water or preparing the flow for discharge, rather than the initial sizing of solids.