CME Water & Wastewater Systems Flashcards
6 cards from real CME practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CME Water & Wastewater Systems flashcards as text
What is the primary goal of water main flushing programs in municipal distribution systems?
Answer: Remove sediment, biofilm, and disinfection byproducts to maintain water quality
Routine flushing programs remove accumulated sediments, biofilm, and disinfection byproducts that degrade water quality and cause customer complaints.
Which type of valve is most commonly used for isolation of water mains to allow repairs or shutdowns?
Answer: Gate valve or resilient-seated gate valve
Gate valves and resilient-seated gate valves are the standard isolation valves in water distribution systems because they provide full-bore flow with minimal head loss when open.
What is biological nutrient removal (BNR) designed to eliminate from wastewater effluent?
Answer: Nitrogen and phosphorus that cause eutrophication
BNR processes use specialized microbial communities to remove nitrogen and phosphorus, preventing nutrient loading that causes algal blooms and dead zones in receiving waters.
What is the function of a pressure reducing valve (PRV) in a water distribution system?
Answer: Reduce higher upstream pressure to a lower, controlled downstream pressure
PRVs protect lower-elevation distribution zones from excess pressure by automatically reducing high upstream pressure to a set downstream value.
Under the Clean Water Act Section 404, what is required before placing fill material in US waters and wetlands for municipal infrastructure projects?
Answer: Section 404 permit from the US Army Corps of Engineers
Section 404 requires a permit from the USACE before discharging dredged or fill material into waters of the US, including wetlands, for any construction project.
What is 'water age' in distribution system modeling and why is it important?
Answer: The time water has spent in the distribution system, affecting disinfectant residual and water quality
Water age (residence time) measures how long water has been in the system; excessive water age depletes chlorine residuals and promotes microbial growth, degrading quality.