NY Water/Wastewater Operator key terms

A treatment step where a chemical such as alum or ferric chloride is rapidly mixed into water to neutralize the electrical charges on suspended particles so they can begin to clump together.

Gentle, slow stirring of chemically treated water that encourages small destabilized particles to collide and grow into larger, settleable clumps called floc.

A gravity process in which water sits quietly in a basin long enough for heavier suspended solids and floc to settle to the bottom as sludge.

Passing water through a bed of sand, anthracite, or other media to remove remaining particles, floc, and many microorganisms that did not settle out earlier.

Reversing flow upward through a filter at a high rate to lift and scrub the media, flushing trapped solids to waste so the filter can run efficiently again.

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

The unit (NTU) used to report turbidity measured by the light-scattering method; regulations set strict upper limits on finished-water NTU values and require continuous monitoring.

The product of disinfectant residual concentration (C) and contact time (T) used to demonstrate that a required level of pathogen inactivation has been achieved.

Compounds such as trihalomethanes and haloacetic acids that form when chlorine or other disinfectants react with naturally occurring organic matter in treated water.

A measurement of the organic material in source water that can react with disinfectants to form byproducts and can support biological growth in the distribution system.

A bench-scale procedure using several stirred beakers to compare coagulant doses and pH conditions and select the best treatment settings for the plant.

The period a filter operates between backwashes, during which head loss rises and effluent quality may begin to degrade; operators end the run on turbidity or head loss limits.

The network of pipes, storage tanks, pumps, and valves that carries finished drinking water from the treatment plant to customers while maintaining adequate pressure and residual disinfectant.

The amount of chlorine still present in water after treatment and travel through pipes; it protects against contamination and must be maintained within a required range.

Any actual or potential link between the drinking water supply and a source of nonpotable water or contamination that could allow backflow into the distribution system.

An approved assembly such as a reduced-pressure-zone device or air gap that stops water from flowing backward from a customer's plumbing into the public water main.

A public notice telling customers to boil tap water before drinking, cooking, or brushing teeth because the supply may be contaminated or treatment has been interrupted.

Extraneous water entering a sanitary sewer, through direct connections like sump pumps (inflow) or through cracks and joints (infiltration), which adds flow the treatment plant must handle.

A release of untreated sewage from a sanitary sewer system before it reaches the treatment plant, often caused by blockages, root intrusion, or wet-weather flow exceeding capacity.

A discharge of mixed stormwater and raw sewage from a system that carries both in one pipe when heavy rain exceeds the capacity of the interceptor or treatment plant.

A field method that blows nonhazardous smoke into a sewer line to reveal broken pipes, illegal connections, and cross connections where smoke escapes.

A secondary treatment process in which a mixed community of microorganisms is kept suspended in aerated wastewater and consumes dissolved organic matter.

The concentration of microorganisms and solids suspended in the aeration tank, used with other measurements to set wasting rates and control the activated sludge process.

Settled biomass collected in the secondary clarifier and pumped back to the aeration tank to maintain a sufficient population of organisms for treatment.

Excess biomass removed from the treatment process to control the amount of solids in the system and keep the sludge age within a target range.

The average time solids remain in the activated sludge system, calculated from the mass of solids in the aeration tank divided by the daily solids leaving the system.

A settling tank after aeration where activated sludge floc settles to the bottom and is separated from the clarified effluent that flows on for disinfection or discharge.

A test measuring the oxygen consumed by microorganisms breaking down organic matter in a sample over a set period, commonly five days, used to gauge treatment performance and permit compliance.

The mass of solid particles captured by filtering a water or wastewater sample, reported in milligrams per liter and commonly limited in discharge permits.

The biological conversion of ammonia to nitrite and then nitrate by specialized bacteria, a process that consumes oxygen and alkalinity in the aeration tank.

The conversion of nitrate to nitrogen gas by bacteria under low-oxygen conditions, used to remove total nitrogen from wastewater before discharge.

The maximum amount of a pollutant a waterbody can receive and still meet water quality standards, allocated among point and nonpoint sources under the Clean Water Act.

The federal permitting program under the Clean Water Act that sets limits on pollutants discharged from wastewater and stormwater outfalls to waters of the United States.

A periodic report a permittee submits showing sampling results and flow data, demonstrating compliance with the effluent limits in its discharge permit.

A drinking water regulation requiring systems to monitor for total coliform bacteria and investigate when samples are positive, signaling possible treatment or distribution problems.

A drinking water regulation that requires systems to control corrosion and sample high-risk customer taps to limit lead and copper levels at the point of use.

An annual notice that community water systems must provide to customers summarizing source water, detected contaminants, compliance status, and health information.

The land area that drains rainfall and runoff into a particular river, lake, or reservoir, and whose activities affect the quality of the source water.

Voluntary and regulatory measures to prevent contamination of lakes, rivers, and wells used for drinking water, such as land-use controls and spill response planning.

The controlled procedure for entering a space with limited openings and poor ventilation that is not meant for continuous occupancy, requiring testing, ventilation, a permit, and an attendant.

A toxic, flammable gas with a rotten-egg odor produced by decaying organic matter in sewers; it deadens the sense of smell and can be fatal in confined spaces.

A flammable, oxygen-displacing gas generated by anaerobic decomposition in sewers and digesters; it forms explosive mixtures and must be monitored before and during confined space work.

A safety procedure that isolates energy sources with locks and warning tags so equipment cannot be started while workers service or repair it.

The practices for handling and storing chlorine gas, including leak detection, ventilation, respiratory protection, and emergency response, because the gas is highly toxic.