CT Water Operator key terms

The process of adding a chemical such as alum to water so that tiny suspended particles clump together and can be removed. It neutralizes the electrical charges that keep particles apart.

Gentle, slow mixing of water after coagulation that encourages small particle clumps to collide and grow into larger, heavier masses called floc that settle out more easily.

The visible clump of particles, chemicals, and organic matter formed during coagulation and flocculation. Floc is heavy enough to settle in a clarifier or be trapped in a filter.

A treatment step in which water sits quietly in a basin so heavier particles and floc settle to the bottom as sludge, leaving clearer water to flow onward to filters.

A large settling basin where floc and solids sink to the bottom and are removed as sludge. Clear water leaves over a weir at the top for further treatment.

Passing water through a bed of sand, anthracite, or other media to trap remaining particles and some microorganisms. It is a key barrier before disinfection.

Reversing the flow of water upward through a filter to flush out trapped particles and restore the filter's ability to clean water. It is done on a schedule or when head loss is high.

The drop in water pressure as water moves through a filter or pipe. Rising filter head loss signals that the media is clogging and backwashing is needed.

Killing or inactivating harmful microorganisms in water using chlorine, chloramine, ozone, or ultraviolet light. It is the most important treatment step for preventing waterborne disease.

A measure of disinfection strength calculated by multiplying disinfectant concentration (C) by contact time (T). Higher CT values mean more germ-killing power.

The length of time water is in contact with a disinfectant before it reaches the first customer. Adequate contact time is required for disinfection to work.

The amount of chlorine still present in water after treatment. It protects water from contamination as it travels through the distribution system.

The cloudiness of water caused by suspended particles. It is measured in nephelometric turbidity units (NTU) and can shield microorganisms from disinfection.

A laboratory instrument that measures turbidity by shining light through a water sample and detecting how much light is scattered by particles.

A scale from 0 to 14 that measures how acidic or basic water is. pH affects coagulation, disinfection efficiency, and corrosion of pipes.

The gradual wearing away of metal pipes and fixtures by chemical action in water. It can release lead and copper into drinking water and damage infrastructure.

A federal regulation that requires water systems to monitor for lead and copper at customer taps and use corrosion control to keep these metals out of drinking water.

The highest concentration of a contaminant allowed in drinking water under federal and state rules. MCLs are enforceable limits set to protect public health.

A non-enforceable health-based target for a contaminant, set at a level where no known or expected health effects occur. It is often lower than the enforceable MCL.

A rule that sets an enforceable standard for a contaminant that poses a health risk, such as bacteria, nitrate, or lead. Systems must meet these limits.

A non-enforceable guideline for contaminants that affect taste, odor, color, or appearance rather than health. Examples include iron and manganese.

A regulation requiring systems to test for coliform bacteria, which indicate possible contamination. Positive samples can trigger repeat testing and public notice.

A group of bacteria used as indicator organisms in drinking water. Their presence suggests the system may be contaminated or that treatment is not working properly.

A public health notice telling customers to boil tap water before drinking, cooking, or brushing teeth because the water may contain harmful microorganisms.

Any actual or potential link between a drinking water system and a source of contamination, such as a hose in a chemical tank. It can allow backflow of pollutants into clean water.

A mechanical assembly that stops water from flowing backward into the drinking water supply. Examples include reduced-pressure zone valves and double check valves.

A physical separation between a water outlet and the highest possible level of a contaminating liquid. It is the most reliable form of backflow prevention.

A large pipe that carries treated water through streets to serve many properties. Main breaks can cause pressure loss and contamination risk.

The network of pipes, storage tanks, pumps, and valves that delivers treated water from the plant to homes and businesses while maintaining adequate pressure.

A structure that holds treated water to meet peak demand, provide fire flow, and keep pressure steady. Tanks must be protected from contamination and stagnation.

A loud banging or pressure surge in pipes caused by a sudden stop in water flow, such as a fast-closing valve. It can damage pipes and joints.

A rapid, temporary increase in pressure in a water pipe, often from pump starts or valve changes. Repeated surges stress pipes and can cause breaks.

The settled solids removed from clarifiers and filter backwash water. Sludge must be handled, dewatered, and disposed of properly.

An enclosed area with limited entry or exit that is not designed for continuous occupancy, such as a vault or wet well. Entry requires a permit and safety precautions.

A safety procedure that physically locks and tags energy sources, such as pumps or breakers, so equipment cannot start while workers service it.

Gear such as gloves, goggles, respirators, and hard hats worn to protect workers from hazards. It is the last line of defense after other controls.

An annual report that water systems must provide to customers describing the quality of their drinking water, including detected contaminants and their levels.

The required process of informing customers when a water system violates a regulation or faces a health risk, including the timing and method of notice.