GA Water/WW Operator key terms

A treatment step in which a chemical such as alum is rapidly mixed into water to neutralize the electrical charges that keep tiny particles apart so they can clump together.

Gentle, slow mixing that encourages the tiny particles destabilized during coagulation to collide and stick together, forming larger, heavier clumps called floc that can settle out of the water.

A settling process in which water rests quietly in a basin long enough for heavier suspended particles and floc to sink to the bottom, producing clearer water for the filters.

Passing water through a bed of sand and gravel at a fairly high rate to trap remaining particles; the filter is cleaned periodically by reversing flow in a backwash.

A process that kills or inactivates harmful microorganisms in drinking water, usually by adding chlorine but sometimes with ultraviolet light or ozone, leaving a residual to protect the distribution system.

The product of disinfectant concentration in milligrams per liter and effective contact time in minutes, used to judge whether a disease-causing organism has been sufficiently inactivated.

A buried pipe that carries treated water through the distribution system to serve fire hydrants and customer service lines; common materials include ductile iron, PVC, and concrete pressure pipe.

A valved connection on a water main that supplies water for firefighting and is also used for flushing mains, testing flow, and checking system pressure.

Any actual or potential link between the drinking water system and a source of contamination, such as a submerged hose in a chemical tank, that could allow backflow into potable water.

A mechanical assembly such as a reduced-pressure-zone valve or double check valve installed to stop contaminated water from reversing flow into the drinking water supply.

A pressure surge caused by a sudden change in flow velocity, such as rapidly closing a valve, that travels through piping and can damage pipes, joints, and fittings.

The small amount of chlorine remaining in water after treatment, measured in the distribution system to confirm that disinfection protection continues as water travels to customers.

A biological treatment process in which a mixed community of microorganisms consumes organic matter in aerated wastewater, and the solids are settled and returned to the aeration basin.

A tank where wastewater is mixed with air or oxygen and microorganisms so that bacteria can break down dissolved organic material in the water.

A settling tank after biological treatment where microorganisms and solids sink to the bottom and are separated from the treated liquid, which flows on to disinfection.

Solids collected in the secondary clarifier that are pumped back to the aeration basin to maintain a healthy population of microorganisms for treating incoming wastewater.

A calculated number, based on the 30-minute settled sludge volume and mixed liquor suspended solids, that indicates how well sludge settles and compacts in the clarifier.

The amount of oxygen dissolved in water, measured in milligrams per liter, which must be kept high enough in aeration basins to support the bacteria that treat wastewater.

A pipe that carries wastewater downhill by gravity, designed with a minimum slope so solids stay suspended and flow to a lift station or treatment plant.

A pressurized pipe that carries wastewater pumped by a lift station uphill or over terrain where a gravity sewer cannot maintain adequate slope.

A facility with pumps and a wet well that raises wastewater from a lower elevation to a higher one so it can continue flowing by gravity.

Groundwater that leaks into sewers through defects (infiltration) plus storm water and other clear water that enters through improper connections (inflow), adding excess flow to the system.

The release of untreated wastewater from a sanitary sewer system before it reaches the treatment plant, often caused by blockages or excess flow, and required to be reported to regulators.

A space large enough to enter, with limited entry or exit, and not designed for continuous occupancy, such as a manhole or wet well, requiring special entry procedures.

A safety procedure that isolates energy sources with locks and tags before equipment is serviced, preventing accidental startup or release of stored energy.

Clothing and devices such as gloves, safety glasses, respirators, and boots worn to protect a worker from hazards encountered on the job.

A toxic, flammable gas with a rotten-egg odor produced by decaying organic matter in sewers; it can deaden the sense of smell and cause unconsciousness at high concentrations.

A method such as sloping, shoring, or a trench box used to prevent cave-ins and protect workers in excavations, required when trenches reach a certain depth.

The federal law that authorizes EPA to set drinking water standards and requires public water systems to monitor and report on contaminants; states such as Georgia carry out primacy enforcement.

The highest concentration of a contaminant allowed in drinking water under federal and state rules, set as close to health-based goals as feasible with available treatment.

A required treatment process or practice, such as filtration or corrosion control, used when a contaminant cannot be reliably measured at low levels or has no practical MCL.

The federal law that regulates discharges of pollutants into surface waters and sets the framework for NPDES permits and wastewater treatment requirements.

A permit issued under the Clean Water Act that sets limits on what pollutants and how much a facility may discharge to a receiving water, plus monitoring and reporting requirements.

A measure of how cloudy water is due to suspended particles; it is reported in nephelometric turbidity units and is a key indicator of filtration and disinfection effectiveness.

A laboratory test measuring the oxygen consumed by microorganisms as they break down organic matter in a water sample over five days at 20 degrees Celsius, used to gauge pollution strength.

The concentration of solid particles suspended in water that are captured by passing a sample through a glass-fiber filter and drying it, reported in milligrams per liter.

A written record tracking who collected, handled, and analyzed a sample from the moment of collection to reporting, ensuring the sample's integrity for regulatory purposes.

A single sample collected at one place and time, used when conditions may change quickly or when the parameter cannot be preserved or composited.

A sample made by combining portions collected at set times or flow intervals, giving an average picture of water quality over a period.

A group of bacteria used as an indicator of treatment effectiveness and possible contamination; their presence triggers repeat sampling and public notice requirements.