Tennessee Wastewater Operator Practice Exam

What is one disadvantage of using comminutors and grinders in wastewater treatment?

1. They improve energy efficiency

2. Shredded material reduces treatment capacity downstream

3. They are cost-effective

4. They eliminate odors completely

The correct answer is: Shredded material reduces treatment capacity downstream

Using comminutors and grinders in wastewater treatment can lead to reduced treatment capacity downstream due to the way they process solid waste. When these devices shred waste, they create smaller particles, which can increase the total suspended solids in the wastewater stream. This can, in turn, overload subsequent treatment processes such as clarifiers and biological treatment systems, as those systems may struggle to handle the increased concentration of smaller solids. Additionally, while comminutors and grinders serve the purpose of breaking down larger solids to prevent clogs and jams in the system, this can lead to a situation where there is more material to manage. The increased surface area and particle size reduction can affect sedimentation rates and mechanical operations, therefore impacting the efficiency and effectiveness of downstream treatment processes. This decline in treatment capacity is a critical consideration for wastewater operators, as it can lead to inefficiencies and may even necessitate more frequent maintenance or upgrades to the treatment infrastructure to adequately handle the altered loading conditions.