OR Water/Wastewater 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.
- Turbidity
- A measure of light scattering by suspended particles in water, reported in nephelometric turbidity units (NTU); it indicates particle presence but not specific pathogen levels.
- Alkalinity
- The acid-neutralizing capacity of water, usually reported as mg/L CaCO3; it buffers pH and affects coagulation and corrosion control.
- Hardness
- The concentration of dissolved calcium and magnesium in water, expressed as mg/L CaCO3; it causes scale and affects softening needs.
- Total organic carbon
- A measure of organic matter in water; TOC reacts with disinfectants to form byproducts and increases coagulant demand.
- Coagulation
- The process of destabilizing suspended particles by neutralizing their surface charge so they can collide and form larger flocs.
- Flocculation
- Gentle mixing that promotes collisions among destabilized particles, allowing them to aggregate into settleable flocs.
- Overflow rate
- The flow divided by the sedimentation basin surface area (Q/A); it is a key design and performance parameter for clarifiers.
- Lime-soda softening
- A precipitation process that removes calcium and magnesium hardness by adding lime and soda ash, forming calcium carbonate and magnesium hydroxide solids.
- Water age
- The time water resides in a distribution system or storage tank; high age can reduce disinfectant residual and increase DBP formation.
- Cross-connection
- Any actual or potential link between a potable water system and a nonpotable source that could allow backflow contamination.
- Backflow prevention
- Devices or practices such as air gaps and reduced-pressure zone assemblies that stop reverse flow of nonpotable water into potable systems.
- Thermal stratification
- Layering of water in storage tanks due to temperature differences; it can cause stagnant zones and uneven disinfectant residual.
- Infiltration
- Groundwater that enters a sewer system through defective pipes, joints, manholes, or connections, increasing wastewater flow.
- Inflow
- Stormwater or groundwater that enters sewers through direct connections such as roof drains, sump pumps, or manhole covers.
- Self-cleansing velocity
- The minimum flow velocity in a sewer that keeps solids suspended and prevents deposition, commonly about 2 feet per second.
- Force main
- A pressurized pipeline that carries pumped wastewater from a lift station to a gravity sewer or treatment plant.
- Activated sludge
- A biological treatment process in which aerobic microorganisms consume organic matter in an aerated basin, followed by solids separation.
- Solids retention time
- The average time biomass remains in an activated sludge system; it controls treatment performance and sludge production.
- Nitrification
- The biological oxidation of ammonia to nitrite and then nitrate by aerobic bacteria, consuming oxygen and alkalinity.
- Sludge volume index
- A measure of sludge settleability calculated from settled sludge volume and MLSS; high values indicate poor settling and possible bulking.
- CT value
- The product of disinfectant residual concentration and contact time; it is used to assess disinfection effectiveness for a given pathogen.
- Breakpoint chlorination
- The chlorine dose at which demand is satisfied and additional chlorine produces a free chlorine residual.
- Trihalomethanes
- A group of disinfection byproducts formed when chlorine reacts with organic matter; they are regulated in drinking water.
- Chloramine
- A disinfectant formed by combining chlorine with ammonia; it provides a persistent residual but is weaker than free chlorine.
- Composite sample
- A sample made by combining portions collected over time or space to represent average conditions, often used for variable wastewater flows.
- Chain of custody
- Documentation that tracks sample possession, handling, and transfer to preserve legal and analytical integrity.
- Percent removal
- Calculated as influent concentration minus effluent concentration, divided by influent concentration, multiplied by 100.
- Detention time
- The theoretical time water or wastewater remains in a tank, calculated as volume divided by flow.
- Confined space
- A space with limited entry or exit that is not designed for continuous occupancy and may contain hazardous atmospheres or engulfment hazards.
- Lockout/tagout
- A safety procedure that isolates hazardous energy sources and applies locks and tags before maintenance to prevent accidental startup.
- Maximum contaminant level
- The highest allowable concentration of a contaminant in drinking water under the Safe Drinking Water Act.
- NPDES permit
- A permit issued under the Clean Water Act that regulates point source discharges and sets monitoring and effluent limits.