Water Treatment Operator Class I flashcards
Water Treatment Operator Class I · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Groundwater versus surface water
- Groundwater usually has lower turbidity and TOC but higher hardness, iron, and dissolved solids; surface water has variable turbidity and higher microbial and DBP-precursor loading.
- Turbidity
- An optical measure of light scattering by suspended particles, reported in NTU; it is not a direct pathogen count but indicates how well filtration is working.
- Langelier Saturation Index
- An index calculated as measured pH minus the pH of calcium carbonate saturation; positive values indicate a scaling tendency and negative values indicate a corrosive tendency.
- Alkalinity
- The acid-neutralizing capacity of water, expressed as mg/L CaCO3; it buffers pH and supplies the bicarbonate that alum and ferric coagulants consume.
- Jar test
- A bench-scale test that mixes a coagulant at several doses and pH values under identical rapid mix, flocculation, and settling to identify the best dose.
- Velocity gradient G
- A measure of mixing intensity in reciprocal seconds; rapid mix typically uses 300 to 1000 per second and flocculation uses 10 to 75 per second.
- Surface overflow rate
- The clarifier loading equal to flow divided by surface area, expressed in gpm/ft2; particles settling faster than this rate are removed in the basin.
- Alum alkalinity consumption
- Each mg/L of alum dosed consumes roughly 0.45 to 0.5 mg/L of alkalinity as CaCO3, so low-alkalinity waters may need lime or caustic added.
- Effective size
- The media particle diameter at which 10 percent of the bed by weight is finer, designated d10; it governs head loss and the required media depth.
- Uniformity coefficient
- The ratio of d60 to d10 for filter media; values near 1.3 to 1.5 indicate a narrowly graded bed that backwashes evenly.
- Filter backwash expansion
- Media bed expansion of about 20 to 50 percent, produced by backwash rates of 15 to 20 gpm/ft2 for 10 to 15 minutes, clears accumulated solids.
- Combined filter effluent limit
- Under the SWTR, combined filter effluent turbidity must be 0.3 NTU or less in at least 95 percent of monthly samples and never exceed 1 NTU.
- CT value
- The product of disinfectant residual concentration in mg/L and contact time in minutes; the required CT varies with disinfectant, pH, temperature, and target log inactivation.
- Breakpoint chlorination
- The chlorine dose at which all ammonia has been oxidized and free chlorine residual begins to persist; beyond the breakpoint residual rises nearly one to one with dose.
- TTHM MCL
- The Stage 2 maximum contaminant level for total trihalomethanes is 80 micrograms per liter, evaluated as a locational running annual average at each monitoring site.
- Enhanced coagulation
- A treatment strategy that raises coagulant dose or lowers pH beyond normal practice to remove total organic carbon, the precursor to trihalomethanes and haloacetic acids.
- Affinity laws
- For a centrifugal pump at constant impeller diameter, flow varies with speed, head varies with speed squared, and power varies with speed cubed.
- NPSH available
- The absolute pressure head at the pump suction above the liquid vapor pressure; it must exceed the pump's required NPSH or cavitation will damage the impeller.
- Brake horsepower formula
- Pump power in horsepower equals flow in gpm times head in feet times specific gravity, divided by 3960 times the pump efficiency expressed as a decimal.
- Water hammer
- A pressure surge caused by a rapid velocity change when a valve closes or a pump stops; controlled with slow-closing valves, surge tanks, and air chambers.
- DPD method
- A colorimetric procedure using N,N-diethyl-p-phenylenediamine to measure free and total chlorine residual in both field and laboratory testing.
- Formazin turbidity standard
- The primary reference suspension used to calibrate nephelometric turbidimeters; it is prepared from hydrazine sulfate and hexamethylenetetramine and assigned NTU values.
- Chlorine residual holding time
- Chlorine residual and pH samples must be analyzed within 15 minutes of collection because both parameters change rapidly after the sample is taken.
- Revised Total Coliform Rule
- Requires routine coliform monitoring plus a Level 1 or Level 2 assessment and corrective action when a sample is total-coliform positive or E. coli is detected.
- Pounds formula
- Pounds per day of chemical equals the concentration in mg/L multiplied by the flow in million gallons per day multiplied by 8.34.
- Detention time formula
- Detention time equals basin volume divided by flow rate; units must match, so gallons divided by gallons per minute yields minutes.
- Feet of head to psi
- One pound per square inch equals 2.31 feet of water head, so divide feet of head by 2.31 to obtain pressure in psi.
- Surface loading rate units
- Flow in gallons per minute divided by clarifier surface area in square feet gives gpm/ft2, the overflow rate that governs particle removal.
- Permit-required confined space
- A space with limited entry that is not designed for occupancy and may contain a hazardous atmosphere, engulfment, or entrapment; entry requires a permit and attendant.
- Chlorine gas IDLH
- The immediately dangerous to life or health concentration for chlorine is 10 ppm; escape from a release requires supplied-air respirators and upwind evacuation.
- Tier 1 public notice
- Required within 24 hours for violations posing an immediate health risk, such as an E. coli MCL or a situation prompting a boil water order.
- Consumer Confidence Report deadline
- Community water systems must deliver the annual Consumer Confidence Report to customers by July 1, covering monitoring results from the previous calendar year.