Tennessee Wastewater Operator Practice Exam

Which type of pipe is most resistant to corrosion?

1. Copper

2. Steel

3. Polyvinyl chloride

4. Cast iron

The correct answer is: Polyvinyl chloride

Polyvinyl chloride (PVC) is highly resistant to corrosion, making it a preferred choice in many wastewater applications. Unlike metals such as copper and steel, PVC does not corrode or rust when exposed to moisture or corrosive substances, which is a significant advantage in environments that can be harsh, such as sewage systems. Additionally, PVC is chemically inert, meaning it does not react with many substances it may come into contact with in wastewater systems, including acidic or alkaline solutions. This resistance to corrosion not only extends the lifespan of the piping but also reduces maintenance costs associated with repairs or replacements. In contrast, materials like steel and cast iron are prone to rusting and deterioration over time when exposed to moisture, and while copper has good corrosion resistance, it can still be affected by certain chemicals found in wastewater. Thus, PVC emerges as the most durable option in terms of corrosion resistance within these choices.