Question 1005 of 229 · California Water Distribution Operator Exam
Why should a new main be flushed before the disinfectant is added?
Exactly one answer is correct.
You got of questions right. Here on the question pages nobody remembers which ones you got wrong. The trainer saves your progress and asks the mistakes again until they stick.
Or free: the 10 questions most people get wrong
Show solution
Correct answer to question 1005
- D: To remove dirt and debris that would create chlorine demand and shield bacteria
Explanation
Particles exhaust the chlorine and can protect microorganisms from it. Pre-flushing at a high velocity moves most solids out before disinfection starts.
More questions: Disinfection
- 1006Heavily chlorinated water flushed from a main must be dechlorinated before it reaches a storm drain or creek. Which chemical is commonly used?
- 1007Approximately what percentage of available chlorine does calcium hypochlorite (HTH) contain?
- 1008Which form of chlorine is 100 percent available chlorine?
- 1009A chlorine dose of 3.0 mg/L produces a free chlorine residual of 0.8 mg/L after the contact time. What is the chlorine demand?
- 1010Which substances commonly create chlorine demand in a distribution system?
- 1011The total chlorine residual equals which combination?