TX Water/Wastewater Operator key terms

A federal drinking water regulation that sets limits on coliform bacteria in finished water and requires systems to monitor for them at representative points throughout the distribution system. Violations can trigger public notice.

The highest concentration of a regulated contaminant legally allowed in drinking water delivered to customers. MCLs are enforceable standards set as close to health goals as feasible given treatment technology and cost.

A non-enforceable health-based target for a contaminant in drinking water, set at a level with no known or expected health risk. MCLs are set as close to MCLGs as practical.

The required process of informing water customers when a system violates a drinking water standard, fails to monitor, or poses a health risk. Notices must follow tiered deadlines and standard language based on severity.

An annual report that community water systems must deliver to customers summarizing source water, detected contaminants and their levels, compliance status, and health information. It must be distributed by a set deadline each year.

The state-issued credential that qualifies an individual to operate a water or wastewater system at a specified classification level. Certification typically requires passing an exam, meeting experience or education requirements, and completing continuing education.

A credit earned by attending approved training, used to renew an operator certificate. Operators must accumulate a set number of hours within each renewal cycle to keep their license active.

A ranking of a water or wastewater facility based on factors such as treatment complexity, population served, and flow. The classification determines the minimum grade of certified operator required to be in responsible charge.

The certified operator designated as the person in direct responsible charge of a facility's daily operation and maintenance. This person must hold a certificate grade at least equal to the system's classification.

The land area that drains rainfall and snowmelt into a particular stream, river, lake, or aquifer. Source water protection efforts focus on managing land uses and pollution sources within the watershed boundary.

An underground layer of rock or sediment that holds and transmits groundwater in usable quantities. Wells and springs draw from aquifers, which can be confined or unconfined and are recharged by precipitation and surface infiltration.

Water stored beneath the earth's surface in saturated soil and rock formations. It is generally lower in turbidity and microbial contamination than surface water but may contain dissolved minerals, hardness, and contaminants from land use.

Water found in rivers, streams, lakes, and reservoirs that is open to the atmosphere and runoff. It typically requires more treatment than groundwater because of variable turbidity, pathogens, and seasonal quality changes.

Voluntary and regulatory measures taken to prevent contamination of the water bodies or aquifers used for drinking water. Strategies include land acquisition, zoning, spill response planning, and public education within the source area.

A program that delineates the area contributing water to a public well and manages potential contamination sources within that zone. It helps prevent pollutants from reaching the well before treatment is needed.

The rapid mixing of a chemical such as alum into raw water to neutralize the electrical charges that keep small particles apart. This allows particles to stick together so they can be removed in later treatment steps.

Gentle, prolonged stirring of coagulated water that encourages small particles to collide and grow into larger, settleable clumps called floc. Proper mixing energy and time are critical to floc formation.

A treatment step where water sits in a basin long enough for suspended particles and floc to settle to the bottom by gravity. Also called clarification, it produces a sludge that must be managed.

Passing water through a porous medium such as sand, anthracite, or membranes to remove remaining suspended particles and some pathogens. Filters must be backwashed periodically to restore flow and removal efficiency.

Reversing water flow through a filter or treatment unit to flush out accumulated solids and restore capacity. Backwashing is usually triggered by head loss, turbidity breakthrough, or a set time interval.

A measure of water clarity, reflecting how much suspended material scatters light passing through a sample. High turbidity can shield pathogens from disinfection and is a key regulated indicator of treatment performance.

The unit used to report turbidity measured by a nephelometer, which detects light scattered at an angle by particles in a sample. Regulatory limits for filtered water are expressed in NTU.

The drop in pressure or water level as water flows through pipes, filters, or treatment units due to friction and clogging. Rising head loss across a filter signals the need to backwash.

The network of pipes, valves, pumps, meters, and storage that delivers treated water from the treatment plant to customers. It must maintain adequate pressure and keep water safe from contamination after treatment.

A large distribution pipe that carries water through streets and feeds smaller service lines to individual properties. Mains are sized for fire flow and peak demand and are typically buried below frost depth.

The pipe connecting a building or property to the public water main, usually including a meter and shutoff valve. Leaks and cross-connections on service lines are common compliance concerns.

Any actual or potential link between the drinking water supply and a source of contamination or nonpotable water. Cross-connections must be controlled through air gaps, backflow preventers, and inspection programs.

Devices and practices that stop water from flowing backward into the public supply due to backpressure or backsiphonage. Common methods include air gaps, reduced-pressure-zone assemblies, and vacuum breakers.

A reservoir, elevated tank, or standpipe that holds treated water to meet peak demand, fire flow, and pressure needs. Tanks must be protected from contamination and managed to avoid stagnant water and loss of residual disinfectant.

A pipe system that carries only domestic and industrial wastewater, not stormwater, to a treatment plant. Keeping stormwater out protects capacity and prevents overflows.

Extraneous water that enters a sanitary sewer from groundwater seeping through defects (infiltration) or from stormwater connections and drains (inflow). High I/I overloads treatment plants and can cause sanitary sewer overflows.

A facility with pumps that raise wastewater to a higher elevation so it can continue flowing by gravity to the treatment plant. Lift stations require wet wells, controls, and backup power to avoid overflows.

The below-grade chamber at a lift station where incoming wastewater collects before pumps move it. Pump controls are set to start and stop at levels that prevent overflow and excessive cycling.

A pressurized pipe that carries pumped wastewater from a lift station to a point where gravity flow can resume. Force mains may generate odors and corrosion from sulfide buildup.

An unauthorized release of untreated wastewater from a sanitary sewer system, often caused by blockages, I/I, or power failures. SSOs must be reported to regulators and can pose public health and environmental risks.

A wastewater treatment process in which a mixed population of microorganisms consumes organic matter in an aerated basin. The mixture is then settled, with some solids returned to the basin and excess wasted.

Solids settled in the secondary clarifier that are pumped back to the aeration basin to maintain a healthy microorganism population. The RAS rate is adjusted to control sludge age and settling behavior.

Excess microorganisms removed from the activated sludge system and sent to solids handling to control the population and sludge age. The wasting rate strongly affects effluent quality and oxygen demand.

The tank where wastewater is mixed with activated sludge and supplied with oxygen so microorganisms can break down organic matter. Aeration equipment may be diffused air, mechanical, or pure oxygen.

A settling tank that separates the activated sludge mixture into clarified effluent and settled solids. Poor settling, called bulking, can cause solids to carry over into the effluent.

A measure of the oxygen consumed by microorganisms as they decompose organic matter in a sample over a set period, usually five days. It is a primary indicator of wastewater strength and treatment performance.

The concentration of solid particles suspended in water or wastewater, determined by filtering a sample and weighing the dried residue. TSS is a standard permit limit for wastewater effluent and a treatment performance measure.

The process of inactivating or destroying disease-causing microorganisms in water or wastewater, usually with chlorine, ultraviolet light, or ozone. Disinfection differs from sterilization, which destroys all organisms.

The amount of disinfectant remaining in treated water after a set contact time. A detectable residual in the distribution system helps protect against contamination that may enter downstream of the plant.

A disinfection measure calculated by multiplying disinfectant concentration (C) by contact time (T). Higher CT values indicate more effective pathogen inactivation and are compared against required values for compliance.

A chemical formed when disinfectants such as chlorine react with natural organic matter in water. Regulated examples include trihalomethanes and haloacetic acids, which are limited because of long-term health concerns.

A group of bacteria used as indicator organisms to assess the sanitary quality of water. Their presence suggests possible contamination and triggers repeat sampling and corrective action under drinking water rules.

A toxic, flammable gas with a rotten-egg odor produced by anaerobic decomposition in sewers and sludge. It causes corrosion, creates odor complaints, and can be deadly in confined spaces at high concentrations.

An enclosed area with limited entry and exit that is not designed for continuous occupancy and may contain hazardous atmospheres. Entry requires atmospheric testing, ventilation, attendants, and proper permits.

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

A measure of the organic material in water that can react with disinfectants to form byproducts. TOC removal is often monitored and optimized during treatment to control disinfection byproduct formation.

The volume of water or wastewater passing a point per unit time, commonly expressed in million gallons per day or gallons per minute. It is used to size equipment, set chemical doses, and calculate loading.

The average time water or wastewater spends in a tank, calculated by dividing tank volume by flow rate. Detention time affects settling, disinfection, and biological treatment performance.

The amount of a substance or flow applied per unit area or volume of a treatment unit per unit time. Loading rates guide design and operation of filters, clarifiers, and biological systems.

The mass of organic material applied to a biological treatment unit per day, often expressed as pounds of BOD per day per unit volume. It helps operators judge whether the system is over- or under-loaded.

A calculation used to find the mass of a substance in water: pounds equals concentration in milligrams per liter times volume in million gallons times 8.34. It is used for chemical feed and loading calculations.

The amount of a treatment chemical added per unit volume or mass of water, often expressed in milligrams per liter or pounds per day. Correct dosing depends on flow, concentration, and jar testing.