Very Small Water System 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.
- Coagulation
- A treatment step that adds a chemical such as alum to neutralize the surface charge of suspended particles so they can clump together.
- Flocculation
- Gentle, slow mixing that encourages small destabilized particles to collide and grow into larger floc that can settle or be filtered.
- Turbidity
- A measure of light scattering by suspended particles in water, reported in NTU; it indicates treatment effectiveness and possible pathogen presence.
- CT value
- The product of disinfectant residual concentration in mg/L and effective contact time in minutes, used to demonstrate pathogen inactivation.
- Chlorine demand
- The difference between the chlorine dose applied and the residual remaining after a set contact time; it reflects oxidizable material in the water.
- Free chlorine residual
- The portion of chlorine remaining as hypochlorous acid and hypochlorite ion after demand is satisfied; it is the active disinfecting form.
- Filter backwash
- A reverse-flow cleaning process that lifts and expands filter media to release trapped particles, restoring head loss and effluent quality.
- NTU
- Nephelometric turbidity unit, the standard unit for turbidity measured by light scatter; lower values indicate clearer, better-filtered water.
- Disinfectant residual
- The measurable concentration of disinfectant remaining in treated water; it protects against contamination as water travels through the system.
- Minimum pressure
- The lowest allowable distribution pressure, often about 20 psi, maintained to prevent backflow and contamination intrusion into mains.
- Water age
- The average time water spends in the distribution system; high age depletes disinfectant and can increase by-product formation.
- Unidirectional flushing
- A technique that opens hydrants in sequence to create high-velocity flow in one direction, scouring sediment from mains.
- Air gap
- A physical separation between a potable water outlet and a potential contaminant source; it is the most reliable backflow prevention method.
- Reduced-pressure zone assembly
- A testable backflow preventer with two check valves and a relief valve that discharges if pressure reverses, protecting against cross-connections.
- Water hammer
- A pressure surge caused by sudden changes in flow velocity, such as rapid valve closure, which can damage pipes and fittings.
- Dead-end main
- A pipe branch with no looped connection at its far end; water stagnates there, so flushing and residual monitoring are especially important.
- Leak detection
- Finding uncontrolled water loss using methods such as metered night flow, acoustic listening devices, and step testing of zones.
- Chemical feed calibration
- Verifying that a feed pump delivers the intended dose by measuring the volume pumped over a known time and comparing it to flow.
- Daily operating log
- A record of doses, residuals, pressures, flows, and maintenance events that provides the primary evidence of compliance and system performance.
- Sample holding time
- The maximum allowed interval between collecting a sample and analyzing it; exceeding it can invalidate results and require resampling.
- Emergency response plan
- A written document describing actions for loss of power, pressure, or source quality, including notification and alternate supply procedures.
- Boil water notice
- A public advisory issued when water may be contaminated, instructing customers to boil water vigorously before drinking, cooking, or brushing teeth.
- Operator certification
- State-issued credential confirming an operator has passed required exams and maintains continuing education to run a public water system.
- Spare parts inventory
- A stocked supply of critical items such as pump diaphragms, reagents, and seals so treatment can continue during equipment failures.
- Safe Drinking Water Act
- The federal law authorizing EPA to set drinking water standards; states usually enforce them through primacy programs.
- Maximum contaminant level
- The highest allowable concentration of a regulated contaminant in delivered water, set to protect public health.
- Secondary standard
- A non-enforceable EPA guideline for aesthetic qualities such as color, odor, taste, and corrosivity rather than health effects.
- Total coliform rule
- A regulation requiring routine coliform sampling; a positive result triggers repeat testing and assessment for potential contamination.
- Lead action level
- The 90th-percentile tap sample concentration of 0.015 mg/L that triggers corrosion control and public education requirements.
- Consumer Confidence Report
- An annual water quality report delivered to customers by July 1 that describes source water, detected contaminants, and health information.
- Public notification
- Required communication to customers about violations; acute risks require notice within 24 hours, while most others allow up to 30 days.
- TTHM MCL
- The maximum contaminant level of 0.080 mg/L for total trihalomethanes, a group of disinfection by-products, evaluated as a running annual average.