MN Water Operator key terms

A treatment step where a chemical such as alum is rapidly mixed into water so tiny suspended particles clump together into larger, heavier particles that can be removed.

Gentle, slow mixing of chemically treated water that encourages small clumps to collide and grow into larger floc particles, which settle or filter out more easily.

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

Passing water through a bed of sand, anthracite, or other media to remove remaining particles, floc, and some microorganisms before disinfection.

Reversing flow upward through a filter bed to loosen and wash out trapped particles, then disposing of the dirty wash water before returning the filter to service.

A bench-scale test using several beakers to compare chemical doses and mixing conditions, helping operators choose the best coagulant dose for treatment.

A treatment process that kills or inactivates harmful microorganisms in water, usually with chlorine, chloramines, ozone, or ultraviolet light, before it reaches customers.

A disinfection measure equal to disinfectant concentration multiplied by contact time; higher CT generally means more microorganism inactivation under stated conditions.

The amount of chlorine still present in water after treatment and travel through pipes; it shows that disinfection capacity remains and can be measured in the field.

A measure of how cloudy water is because of suspended particles; high turbidity can shield microorganisms and interfere with disinfection.

A buried pipe, usually large in diameter, that carries treated water through streets to serve fire hydrants, valves, and smaller service lines.

The network of pipes, pumps, valves, hydrants, and storage facilities that delivers treated water from the treatment plant to customers.

A valved connection on a water main that lets firefighters draw water and lets utilities flush mains and test flow and pressure.

A pump installed within the distribution system to raise water pressure or move water into a higher-pressure zone or storage facility.

A reservoir in the distribution system that holds treated water for peak demand, fire flow, and emergency supply while helping stabilize system pressure.

Any actual or potential link between drinking water piping and a source of contamination, such as a hose submerged in a chemical tank.

A mechanical assembly or air gap that stops water from flowing backward into the drinking water system, protecting it from contamination at a cross-connection.

A pressure surge caused by a sudden change in water velocity, such as quick valve closure, which can damage pipes and fittings.

A defined area of a distribution system kept within a set pressure range by pumps, valves, or storage so service remains adequate and pipe stress is limited.

A graph showing a pump's flow rate and head relationship, helping operators select equipment and predict performance in a system.

A pump that adds energy to water by spinning an impeller, pushing water outward and creating flow; common in treatment and distribution service.

The formation and collapse of vapor bubbles in a pump when pressure drops too low, causing noise, vibration, and damage to the impeller.

Net positive suction head; the absolute pressure energy available at a pump suction above the liquid's vapor pressure, needed to prevent cavitation.

The vertical height difference between the water level on the suction side and the discharge point, measured in feet or meters.

A rating of the mechanical power a motor can deliver; it must be matched to the pump's power demand with a suitable service factor.

An electronic controller that changes a motor's speed by adjusting electrical frequency, allowing pumps to match flow and save energy.

A measured portion of water collected and handled according to a sampling plan so laboratory results represent the water being monitored.

A group of bacteria used as an indicator of drinking water contamination because their presence suggests inadequate treatment, disinfection, or system integrity.

A laboratory test that estimates the number of general bacteria able to grow on a nutrient medium, used to assess water quality changes.

Chemicals such as trihalomethanes that form when disinfectants react with natural organic matter in water; they are regulated in finished water.

An on-site inspection of a water system's source, treatment, storage, and distribution to identify conditions that could contaminate drinking water.

An enclosed area with limited entry or exit that may contain dangerous air, engulfment hazards, or other serious safety risks and requires special precautions.

A safety procedure that isolates energy sources and applies locks and tags so equipment cannot start while workers service it.

Clothing and gear such as gloves, goggles, respirators, and boots worn at a water facility to reduce exposure to hazards on the job.

Precautions for handling chlorine gas, including ventilation, leak detection, respiratory protection, and emergency plans, because the gas is highly toxic.

The required process of informing customers promptly about drinking water violations, health risks, what they should do, and when to act.

An annual report that community water systems give customers, summarizing water quality, test results, and related health information as required by regulation.

Maintaining accurate logs of treatment, sampling, maintenance, and compliance activities so operators can track performance and demonstrate regulatory compliance during inspections.