IN Water/WW Operator key terms

The process of adding a chemical such as alum to raw water so tiny particles clump together. It neutralizes particle charges and prepares solids for settling and filtration.

Gentle, slow mixing of chemically treated water that encourages small clumps to collide and grow into larger, heavier floc. This step follows coagulation and makes later settling more effective.

A treatment step where water sits in a quiet basin long enough for suspended solids to settle to the bottom. The settled material is removed as sludge and clearer water flows onward.

Passing water through layers of sand, anthracite, or other media to trap remaining particles. Filtration follows settling and removes solids that did not sink, polishing the water before disinfection.

A process that kills or inactivates harmful microorganisms in water, usually with chlorine, chloramine, ozone, or ultraviolet light. It is the final major barrier protecting public health in a treatment plant.

A measure of how cloudy water looks because suspended particles scatter light. High turbidity can hide pathogens and interfere with disinfection, so plants monitor and reduce it.

A disinfection calculation that multiplies the disinfectant concentration (C) by the contact time (T). Operators use it to confirm that enough killing power reaches water under set conditions.

The amount of chlorine still present in water after treatment and travel through pipes. A measurable residual shows the water stayed protected against contamination and is checked throughout the system.

A bench-scale procedure that mixes a sample of raw water with different doses of coagulant. Operators compare how quickly floc forms and settles to choose the best chemical dose.

A large buried pipe that carries treated water from pumps, tanks, or treatment plants through streets to neighborhoods. Mains form the backbone of a distribution system and serve many customers.

A pump placed within a distribution system to raise pressure or move water into a higher pressure zone. It helps maintain adequate flow at homes and hydrants far from the source.

A defined area of a distribution system kept within a chosen pressure range, often by valves, pumps, or tanks. Zones prevent excessive pressure in low areas and low pressure in high areas.

A pressure surge caused by a sudden change in water velocity, such as a fast valve closure or pump stop. It can crack pipes and damage fittings, so operators use slow-closing valves and surge control.

Any actual or potential link between drinking water and a source of contamination, such as a hose in a chemical bucket. Preventing cross-connections is essential to keep treated water safe.

A tested device installed on a water line to stop contaminated water from flowing backward into the drinking water system. Common types include reduced-pressure zone and double-check assemblies.

A tank that holds treated water near customers, balancing demand and supplying extra flow for fires or peak use. It also helps maintain steady pressure across a distribution system.

The wastewater entering a treatment plant or a specific treatment unit. Its flow rate and strength, measured as BOD, solids, and other pollutants, set the load the plant must handle.

A large tank where wastewater slows down so heavy solids settle and grease floats. It removes a substantial share of suspended solids and BOD before biological treatment.

A biological treatment process where a mixture of wastewater and microorganisms is aerated. The microbes consume organic matter, and settled sludge is returned to seed the next batch.

A tank where air or oxygen is mixed into wastewater to support microbes that break down organic material. Mixing also keeps solids suspended and helps oxygen reach the biological community.

Biochemical oxygen demand measures the oxygen that bacteria use while breaking down organic matter in a water sample. It is a common indicator of wastewater strength and treatment performance.

The mass of solid particles, organic and inorganic, that are suspended in wastewater or effluent. It is measured by filtering a sample, drying the residue, and weighing it.

Treated organic solids recovered from wastewater treatment that can be recycled as fertilizer or soil conditioner when they meet regulatory standards. Processing may include digestion, dewatering, and pathogen reduction.

The treated wastewater leaving a plant or treatment unit. Its quality is monitored against permit limits before it is discharged to a river, land, or another receiving environment.

A pipe network that collects wastewater from homes and businesses and carries it to treatment. By design it excludes stormwater, although leaks can let groundwater enter.

A facility with pumps that raise wastewater from a low point so it can continue moving by gravity. Wet wells, controls, and backup power are common features.

Infiltration is groundwater seeping into sewers; inflow is stormwater entering through direct connections such as downspouts or manhole covers. Both add clean water that must be treated.

A discharge of untreated stormwater and sewage when a system carrying both flows exceeds capacity during rain. CSOs are regulated because they release pollutants to receiving waters.

A sewer pipe laid on a downward slope so wastewater flows by gravity without pumping. Proper slope and bedding keep flow moving and help prevent solids from settling.

An enclosed area with limited entry or exit that is not designed for continuous occupancy, such as a wet well or vault. It may hold dangerous air, so entry requires testing and permits.

A safety procedure that isolates energy sources and attaches warning tags before equipment is serviced. It prevents accidental startup or release of stored energy that could injure workers.

A toxic, flammable gas with a rotten-egg odor that forms in sewers and digesters. It can deaden the sense of smell at higher levels, so workers rely on gas detectors.

An engineered support such as shoring, shielding, or sloping that protects workers from cave-ins in an excavation. It is required when trenches reach certain depths or show unstable soil.

The federal law that authorizes national drinking water standards and oversight of public water systems. It sets the framework for contaminant limits, monitoring, reporting, and operator requirements.

The highest concentration of a regulated contaminant allowed in drinking water under federal rules. MCLs are enforceable limits set as close to health goals as treatment technology allows.

A permit issued under the Clean Water Act that limits what pollutants a wastewater plant or other discharger may release. It specifies monitoring, reporting, and effluent limits.

A planned approach to tracking, maintaining, and funding a utility's physical assets over their useful lives. It uses condition data and risk to decide repair, replacement, and spending priorities.

Scheduled inspection, lubrication, adjustment, and part replacement done before equipment fails. It reduces emergency repairs, extends asset life, and helps keep treatment and pumping reliable.