Registered Environmental Protection Engineer key terms

The maximum amount of a pollutant a water body can receive and still meet its water quality standards, allocated among point sources, nonpoint sources, and a margin of safety.

A regulatory license issued under the Clean Water Act that sets effluent limits and monitoring requirements for facilities discharging pollutants from a point source into waters of the United States.

Technology-based numeric limits on pollutant concentrations or mass in wastewater discharges, established by source category and applied through permits regardless of the receiving water's condition.

The Clean Water Act standard applied to existing industrial dischargers of toxic and nonconventional pollutants, requiring the best control level that is economically achievable for the source category.

State-adopted designated uses for a water body plus the numeric and narrative criteria protecting those uses, together forming the benchmark against which water quality and permits are judged.

A component of water quality standards that prevents unnecessary lowering of water quality in high-quality waters and protects existing uses in all waters.

The mass of dissolved oxygen consumed by microorganisms decomposing organic matter in a water sample under specified time and temperature conditions, commonly five days at 20 degrees Celsius.

A measure of oxygen equivalent consumed by oxidizing nearly all organic and some inorganic matter in a sample using a strong chemical oxidant, giving a faster but less biological result than BOD.

The biological stage of wastewater treatment that removes dissolved and colloidal organic matter, typically required to achieve at least 85 percent removal of BOD and total suspended solids.

A biological treatment process in which a mixed culture of microorganisms is aerated with wastewater, forming floc that adsorbs and metabolizes organic matter before separation in a clarifier.

The average period wastewater remains in a treatment unit, calculated as tank volume divided by flow rate, governing contact time for biological and chemical reactions.

The average time microorganisms remain in a biological treatment system, calculated as mass of solids in the system divided by the daily mass wasted, controlling sludge age and nitrification.

The two-step microbial oxidation of ammonia to nitrite and then to nitrate, consuming oxygen and alkalinity and requiring adequate solids retention time for slow-growing nitrifying bacteria.

The anoxic microbial conversion of nitrate to nitrogen gas, used to remove total nitrogen from wastewater and to recover oxygen and alkalinity consumed during nitrification.

Legally enforceable limits on outdoor concentrations of six criteria pollutants, set as primary standards to protect public health and secondary standards to protect public welfare.

A state's enforceable strategy, approved by the federal environmental agency, describing how it will attain and maintain the national ambient air quality standards within its borders.

A geographic region where monitored concentrations of a criteria pollutant meet the applicable national ambient air quality standard, in contrast to a nonattainment area that exceeds it.

A preconstruction permitting program requiring new or modified major stationary sources in nonattainment or pristine areas to install stringent controls and obtain emission offsets.

A permitting program protecting air quality in areas cleaner than the national standards by requiring major new sources to apply best available control technology and demonstrate no adverse impact.

The maximum emission reduction achievable for a new major source, determined case by case considering energy, environmental, and economic impacts, used in prevention of significant deterioration permitting.

The most stringent emission limit achieved in practice or required by any state for a similar source, mandatory for major new sources in nonattainment areas without consideration of cost.

A particulate control device that charges particles in an electric field and collects them on oppositely charged plates, achieving high removal efficiency with low pressure drop.

A particulate control device that passes dust-laden gas through woven or felted bags, capturing particles as a cake that is periodically removed by shaking or reverse pulse cleaning.

A post-combustion nitrogen oxide control technology that injects ammonia or urea over a catalyst to convert nitrogen oxides into nitrogen gas and water vapor.

A nitrogen oxide control method that injects ammonia or urea into a hot flue gas zone without a catalyst, achieving moderate reduction at lower capital cost than catalytic systems.

An air pollution control device that contacts flue gas with a liquid to absorb gaseous pollutants such as sulfur dioxide or to capture particles in droplets.

The federal law governing generation, transportation, treatment, storage, and disposal of solid and hazardous waste, including cradle-to-grave tracking and facility permitting.

The four properties that make a waste hazardous under federal rules: ignitability, corrosivity, reactivity, and toxicity, determined by specified tests or generator knowledge.

A tracking document that accompanies hazardous waste from its point of generation through transport to final disposal, ensuring accountability and confirming receipt by the designated facility.

Rules prohibiting disposal of hazardous waste on land unless it first meets treatment standards, expressed as concentrations or technology requirements, to reduce long-term environmental risk.

The federal statute establishing liability for releases of hazardous substances and funding for cleanup of contaminated sites, commonly known as Superfund.

The formal document selecting the remedy for a Superfund site after feasibility study, stating cleanup objectives, chosen technology, and the rationale for the selection.

The remedial investigation phase that develops and evaluates cleanup alternatives against criteria such as effectiveness, implementability, and cost, leading to the selected remedy.

A non-intrusive investigation of a property's history, records, and visual conditions to identify recognized environmental conditions before acquisition, supporting liability protection.

Liquid that has percolated through waste or contaminated soil, dissolving and carrying pollutants, which must be collected and treated at landfills or remediation sites.

An engineered low-permeability barrier, often compacted clay or geomembrane, placed beneath waste to limit migration of leachate into groundwater.

A detailed public document required for major federal actions significantly affecting the environment, describing impacts, alternatives, and mitigation measures.

An agency determination, supported by an environmental assessment, that a proposed action will not significantly affect the environment and therefore does not require a full impact statement.

The early public process that defines the range of issues, alternatives, and impacts to be examined in an environmental impact statement, focusing effort on significant matters.

A documented, unbroken record of sample possession and handling from collection through analysis, proving integrity and admissibility of monitoring results.

The minimum concentration of a substance that can be measured and reported with a stated confidence that the value exceeds zero, determined from replicate analyses of a fortified sample.

The planned management system and the operational checks, such as blanks, duplicates, and calibration, that together ensure monitoring data meet defined accuracy and precision goals.

A single steady sound level carrying the same acoustic energy as a fluctuating sound over a stated period, commonly used to express environmental noise exposure.

A twenty-four-hour energy-averaged sound level with a ten-decibel penalty added to nighttime levels, reflecting greater sensitivity to noise during sleeping hours.

A single-number rating of how well a building element such as a wall or window attenuates airborne sound, based on laboratory measurements across speech frequencies.