Tennessee Wastewater Operator Practice Exam

What is the most likely cause of a malfunctioning gas chlorination system with normal gas pressure and no injector vacuum?

1. Faulty regulator

2. Insufficient chlorine supply

3. Injector clogged

4. Leaking fittings

The correct answer is: Injector clogged

A malfunctioning gas chlorination system with normal gas pressure and no injector vacuum can often be traced to a clogged injector. The injector is responsible for creating the suction needed to draw chlorine gas into the water stream. When this component becomes obstructed, either from debris or buildup, it disrupts the system's ability to function correctly, leading to a lack of vacuum. This results in chlorine not being injected into the water, even though the gas pressure remains normal. The other options do not directly explain the lack of injector vacuum. A faulty regulator would typically manifest as irregular pressure readings, while insufficient chlorine supply would lead to low availability of gas rather than vacuum issues. Leaking fittings may create pressure loss but wouldn't necessarily cause the injector to fail to create vacuum on its own. Thus, a clogged injector stands out as the most likely cause in this scenario.