SC Water/Wastewater Operator flashcards
SC Water/Wastewater Operator · 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.
- Watershed
- A watershed is all the land area that drains rainfall and snowmelt to a common river, lake, or groundwater recharge point, determining raw water quantity and quality.
- Baseflow
- Baseflow is the portion of streamflow sustained by groundwater discharge during dry periods, when surface runoff is minimal; it supports minimum instream flows and dilution.
- Turbidity
- Turbidity measures suspended particles that scatter light, reported in NTU; high turbidity can shield pathogens, increase disinfectant demand, and interfere with filtration.
- Groundwater under direct influence
- Groundwater under the direct influence of surface water is a well or spring that shows significant risk of pathogen contamination from nearby surface water, requiring additional treatment and monitoring.
- Coagulation
- Coagulation is the rapid mixing of a chemical such as alum or ferric chloride into water to destabilize particle charges so small particles can stick together.
- Flocculation
- Flocculation is gentle, prolonged mixing that encourages destabilized particles to collide and grow into larger, settleable flocs after coagulation.
- Surface overflow rate
- Surface overflow rate is clarifier flow divided by clarifier surface area, expressed as gpd/ft² or m³/m²·d; it controls settling performance and hydraulic loading.
- Jar test
- A jar test is a bench-scale procedure that mixes raw water with varying coagulant doses and pH values to identify the best coagulation and flocculation conditions.
- Water age
- Water age is the average time water remains in pipes and storage tanks; older water can lose disinfectant residual, form byproducts, and support nitrification or biofilm growth.
- Cross-connection
- A cross-connection is any actual or potential link between a potable water system and a nonpotable source that could allow contamination to flow backward into drinking water.
- Unidirectional flushing
- Unidirectional flushing is a planned technique that isolates pipe sections and flushes water in one direction at high velocity to remove sediment and biofilm without spreading contamination.
- Pressure zone
- A pressure zone is a defined area of a distribution system served by one hydraulic grade line, often bounded by pressure-reducing valves or pumps to maintain acceptable pressures.
- Infiltration and inflow
- Infiltration is groundwater entering sewers through defects, while inflow is stormwater entering through direct connections such as roof drains, yard drains, or manhole covers.
- Lift station
- A lift station is a pump facility that raises wastewater from a lower elevation to a higher gravity sewer or treatment plant, usually including wet well, pumps, controls, and emergency power.
- Hydrogen sulfide in sewers
- Hydrogen sulfide forms in sewers when anaerobic bacteria reduce sulfate in wastewater; it causes odors, toxicity, and sulfuric acid corrosion of concrete pipes and manholes.
- Activated sludge
- Activated sludge is a biological wastewater process in which aerobic microorganisms suspended in mixed liquor consume organic matter, forming floc that is settled in a clarifier and returned.
- Solids retention time
- Solids retention time, also called mean cell residence time, is the average time biological solids remain in the activated sludge system; it governs treatment performance and sludge production.
- Sludge volume index
- Sludge volume index is the volume in milliliters occupied by one gram of activated sludge after 30 minutes of settling; low values indicate good settling, high values suggest bulking.
- Nitrification
- Nitrification is the biological oxidation of ammonia to nitrite and then nitrate by nitrifying bacteria, consuming oxygen and alkalinity and requiring adequate solids retention time.
- CT value
- CT is disinfectant residual concentration in mg/L multiplied by contact time in minutes; required CT varies with disinfectant, pH, temperature, and target pathogen.
- Breakpoint chlorination
- Breakpoint chlorination is the point where chlorine demand from ammonia and other substances is satisfied and further chlorine produces a free available residual.
- Trihalomethanes
- Trihalomethanes are disinfection byproducts formed when chlorine reacts with natural organic matter; total THMs are regulated in drinking water and controlled by precursor removal and treatment changes.
- UV disinfection
- UV disinfection uses ultraviolet light, typically at 254 nm, to damage microbial DNA; it provides no residual and requires low-turbidity water and proper lamp dose monitoring.
- Net positive suction head
- Net positive suction head is the absolute pressure energy at a pump suction; available NPSH must exceed required NPSH to prevent cavitation, vibration, and impeller damage.
- Pump affinity laws
- Pump affinity laws state that flow varies with speed, head with speed squared, and power with speed cubed for a geometrically similar pump at constant impeller diameter.
- 4-20 mA signal
- A 4-20 mA signal is an analog instrumentation standard where 4 mA represents the zero or lower range value and 20 mA represents the full-scale value.
- Permit-required confined space
- A permit-required confined space has limited entry and exit, is not designed for continuous occupancy, and contains hazards such as dangerous atmosphere, engulfment, or entrapment, requiring a written permit.
- Atmospheric testing order
- Atmospheric testing for confined space entry checks oxygen first, then flammable gas as percent LEL, then toxic gases such as hydrogen sulfide and carbon monoxide.
- Lockout/tagout
- Lockout/tagout is an energy control procedure that isolates hazardous energy sources with locks and tags before maintenance, preventing unexpected startup or release of stored energy.
- NPDES permit
- An NPDES permit is a Clean Water Act permit that sets effluent limits, monitoring, and reporting requirements for wastewater discharged from a treatment plant to surface waters.
- Consumer Confidence Report
- The Consumer Confidence Report is an annual drinking water report that tells customers about source water, detected contaminants, compliance, and health effects information.
- Pounds formula
- The pounds formula calculates pounds of a substance as concentration in mg/L times flow in MGD times 8.34, the weight in pounds of one gallon of water per mg/L.