Florida Wastewater Practice Test

If more than 40 lbs of chlorine is withdrawn from a 150 lb tank in a 24-hour period, what is the potential consequence?

1. Tank rupture

2. Freezing of the lines

3. Immediate shortage of chlorine

4. Gas diffusion

The correct answer is: Freezing of the lines

The scenario presented involves the withdrawal of a significant amount of chlorine from a tank, which raises concerns about the integrity of the system and the potential for hazards. When more than 40 pounds of chlorine is withdrawn from a 150-pound tank within a 24-hour period, the most relevant consequence pertains to the potential for low temperatures in the lines. Withdrawing chlorine at such a high rate can lead to a drop in pressure and temperature within the tank and connected lines. Chlorine behaves as a gas, and as it is released or utilized, it can cool down rapidly due to the Joule-Thomson effect, where gas expands and cools as pressure is released. If the lines and the remaining gas within the tank begin to freeze due to this rapid expansion and subsequent cooling, it can lead to blockages. Such blockages can pose operational risks and can impede the flow of chlorine. Although immediate shortages and gas diffusion can be consequences of high withdrawal rates, the specific concern of freezing lines highlights a physical and operational risk that can directly impact the system's functionality and efficiency. Thus, understanding the behavior of gases under pressure and the implications of rapid withdrawal rates is crucial in wastewater management and chlorine handling processes.