MI Water Operator flashcards
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32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- CT value
- Product of disinfectant residual concentration in mg/L and contact time in minutes; used to demonstrate log inactivation of pathogens.
- Jar test
- Laboratory procedure that determines optimal coagulant dose and pH by simulating coagulation, flocculation, and settling in beakers.
- Breakpoint chlorination
- Point where added chlorine satisfies demand and free chlorine residual begins increasing; beyond it, free chlorine persists.
- Filter backwash
- Reverse flow through filter media to remove trapped particles; triggered by head loss, turbidity breakthrough, or run time.
- Turbidity limit
- Michigan conventional filtration requires ≤0.3 NTU in 95% of monthly samples and never above 1 NTU.
- Schmutzdecke
- Biological layer on slow sand filter surface that removes particles and pathogens; must be protected and periodically scraped.
- Fluoride MCL
- Primary maximum contaminant level is 4.0 mg/L; secondary standard is 2.0 mg/L; optimal dose typically 0.7 mg/L.
- Chlorine demand
- Difference between chlorine dose and residual after contact time; reflects consumption by organics, iron, manganese, ammonia.
- Minimum distribution pressure
- Twenty psi must be maintained under all conditions; normal operating pressure is typically 40 to 80 psi.
- Coliform MCL
- For systems collecting fewer than 40 samples monthly, more than one total coliform-positive sample triggers the MCL.
- TTHM MCL
- Stage 2 DBPR limits total trihalomethanes to 80 µg/L as a locational running annual average.
- Air gap
- Highest-rated backflow prevention method; a physical separation between the potable water supply and a potential contaminant source, with no submerged outlet.
- Lead action level
- Michigan's 90th-percentile lead action level is 12 ppb, stricter than the federal 15 ppb; exceeding it triggers corrosion control and public education.
- Water age
- Time water spends in the distribution system; high water age raises disinfection byproduct formation and lowers disinfectant residual.
- Hydrant flow test
- Measures available flow and pressure at hydrants to evaluate water main capacity, fire protection, and areas needing flushing or rehabilitation.
- Specific capacity
- Well yield in gallons per minute divided by drawdown in feet; indicates well efficiency and aquifer productivity.
- Drawdown
- Difference between the static water level and the pumping water level in a well while it is being pumped.
- Sanitary well cap
- Vermin-proof cap with gasket that seals the casing top and prevents surface water and debris entry.
- Wellhead protection area
- Land surface around a well where contaminants could reach the well within a specified time, often five years.
- GWUDI
- Groundwater under the direct influence of surface water; requires 4-log virus treatment under the Groundwater Rule.
- Shock chlorination
- Disinfection of a well with a strong chlorine solution, commonly 100 mg/L, held for at least 24 hours.
- Tier 1 public notice
- Required within 24 hours for acute violations such as E. coli MCL or loss of pressure; must reach all consumers.
- Consumer Confidence Report
- Annual water quality report delivered to customers by July 1, summarizing source water and detected contaminants.
- Monthly operating report
- Report of flows, chemical doses, residuals, and compliance data that Michigan systems submit to EGLE.
- Stage 2 DBPR
- Federal rule limiting TTHM to 80 µg/L and HAA5 to 60 µg/L at each distribution monitoring location.
- Groundwater Rule
- Federal rule requiring 4-log virus treatment or monitoring for groundwater systems at risk of fecal contamination.
- Operator certification
- Michigan requires certified treatment and distribution operators for community water supplies, with continuing education units needed for renewal.
- Chlorine gas IDLH
- Immediately dangerous to life or health concentration is 10 ppm; use supplied-air respiratory protection and evacuate upwind.
- Confined space oxygen
- Acceptable entry range is 19.5 to 23.5 percent oxygen; entry requires a permit and atmospheric testing.
- Trench protective system
- Required at five feet depth or deeper; spoil piles kept at least two feet from the edge.
- Boil water advisory
- Issued when pressure falls below 20 psi or contamination is suspected; Tier 1 notice within 24 hours.
- Lockout tagout
- Isolate and lock energy sources, then verify zero energy before servicing pumps, motors, or electrical equipment.