مسرد بيئي R

من موسوعة العلوم العربية
مراجعة 10:34، 22 أكتوبر 2011 بواسطة إدارة الموسوعة (نقاش | مساهمات) (أنشأ الصفحة ب'المعجم البيئي مشروع قيد العمل يحتاج ترجمة وإضافات A - B - [[مسرد بيئي...')
(فرق) → مراجعة أقدم | المراجعة الحالية (فرق) | مراجعة أحدث ← (فرق)
اذهب إلى التنقل اذهب إلى البحث

المعجم البيئي مشروع قيد العمل يحتاج ترجمة وإضافات

A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z



  • R&B Filtration Sludge dewatering equipment product line of Baker Process.
  • R&D Research and development.
  • RA (1) Reasonable alternative. (2) Regulatory alternatives. (3) Regulatory analy­
  • sis. (4) Remedial action. (5) Resource allocation. (6) Risk analysis. (7) Risk
  • assessment. rabble arms Rotating rake arms used to scrape sludge in a multiple hearth furnace. RAC Radiation Advisory Committee. race track See “oxidation ditch.” RACM (1) See “reasonably available control measures (RACM).” (2) See “regu­
  • lated asbestos-containing material (RACM).” Racod™ Biological sensor to provide a rapid indication of BOD by USFilter/Wal­
  • lace & Tiernan. RACT See “reasonably available control technology (RACT).” rad Radiation absorbed dose. A measure of the absorbed dose of radiation. Radial Filter Tertiary .ltration system by Waterlink/Aero-Mod Systems. radial .ow Direction of .ow from either the center to the periphery or the periph­
  • ery to center. Radial Plate Dryer Sludge drying system by B-H Process Systems. radial well A well system where one or more cylindrical screens are driven hor­
  • izontally into a water-bearing stratum, radiating from a central sump. radiation The transfer of energy by means of electromagnetic waves or high-speed particles. radiation sickness A sickness that results from overexposure to radiation whose symptoms may include nausea, bleeding, hair loss, and death. radiation standards Regulations that set maximum exposure limits for protection of the public from radioactive materials.
  • radical A combination of atoms in a molecule that remains unchanged throughout most chemical reactions.
  • Radicator Solid waste incinerator by Hitachi Metals America, Ltd.
  • radioactive A description of an unstable atom that undergoes spontaneous disin­tegration and gives off radiant energy in the form of particles or rays.
  • radioactive material A material that spontaneously emits ionizing radiation hav­ing a speci.c activity greater than 0.002 microcuries per gram.
  • radioactivity The spontaneous decay or disintegration of an atomic nucleus that is accompanied by radiation.
  • radioisotopes Chemical variants of an element with potentially oncogenic, terato­genic, and mutagenic effects on the human body.
  • radionuclide An atom that spontaneously undergoes radioactive decay.
  • radius of vulnerability zone The maximum distance from the point of release of a hazardous substance in which the airborne concentration could reach the level of concern under speci.ed weather conditions.
  • radon A radioactive gas produced from the decay of radium which may be inhaled when the gas is released from groundwater, often during showering, bathing, or cooking.
  • radon daughters Short-lived radioactive compounds produced during the decay of radon that decay into longer-lived lead isotopes. Also called radon progeny or radon decay products.
  • RADS See “reactive airways dysfunction syndrome (RADS).”
  • radwaste Radioactive waste.
  • raf.nate The extracted waste stream containing contaminants in a solvent extrac­tion process.
  • railway softening See “excess lime-soda softening.”
  • rain forest See “tropical rain forest.”
  • Rainlogger Stormwater sampling unit by American Sigma, Inc.
  • Rake-O-Matic Hydraulically operated, reciprocating rake bar screen formerly offered by BIF.
  • Ram® Waste compactor by S&G Enterprises, Inc.
  • RAMP Rural Abandoned Mine Program.
  • Rampactor Compaction device by SRS Industrial Engineering.
  • Ram-Rod Dewatering screw press by Ketema, Inc.
  • RAMS Regional Air Monitoring System.
  • Ramtube® Reverse pulse self-cleaning baghouse by Farr Co.
  • Ranney® Well screen and caisson intake products by Layne Christensen, Ranney Division.
  • Ranney Intake Surface water intake system utilizing a passive screen/caisson arrangement by Layne Christensen, Ranney Division.
  • RAP Remedial action plan.
  • RaPID Assay™ Reagent kit for .eld soil analysis by Strategic Diagnostics, Inc.
  • Rapid Decanter® Solid bowl centrifuge by Krauss Maffei Corp.
  • Rapid Gravity Dewatering™ Inclined gravity .lter for sludge dewatering by Wil-Flow, Inc.
  • rapid mix A physical water treatment process that involves rapid and complete mixing of coagulants or conditioning chemicals.
  • rapid sand .lter Granular media .lter in which water .ows downward through a sand .lter bed at rates typically ranging from 80 to 320 L/min/m2 (2 to 8 gpm/sq ft) of surface area.
  • Rapidor Pressure leaf .lter by Liquid-Solids Separation Corp.
  • RAPS Regional Air Pollution Study.
  • RAS See “return activated sludge (RAS).”
  • rasp A machine that grinds waste into a manageable size and controls odors.
  • RATA See “relative accuracy test audit (RATA).”
  • rated capacity The basis for calculating the period of time or volume of treated product delivered by a water softener, demineralizer, or .lter between regen­erations, backwashing, or servicing.
  • RatedAeration® Circular steel-activated sludge wastewater treatment plant for­merly offered by USFilter/Envirex.
  • rate-of-.ow controller A device that automatically controls the rate of .ow of a .uid.
  • Ratio Turbidimeter by Hach Co.
  • RatioFlo™ Flow-to-polymer ratio valve by USFilter/Stranco.
  • raw sewage Untreated wastewater and its contents.
  • raw sludge Undigested sludge recently removed from a sedimentation basin.
  • raw water Untreated surface or groundwater.
  • Raymond Sludge incinerator formerly offered by GL&V/Dorr-Oliver, Inc.
  • Raymond Process An aquifer bioremediation technology where groundwater is
  • recovered from the aquifer, treated, amended with nutrients and oxygen, and
  • reinjected.
  • RaySolv Product group of CSM Worldwide/RaySolv.
  • Raysorb Activated carbon VOC control system by CSM Worldwide/RaySolv.
  • RBC See “rotating biological contactor (RBC).”
  • RBCA See “Risk Based Corrective Action (RBCA).”
  • RCC Resource Conservation Co.
  • RCO See “regenerative catalytic oxidizer (RCO).”
  • RCP Reinforced concrete pipe.
  • RCRA See “Resource Conservation and Recovery Act (RCRA).”
  • RCRIS Resource Conservation and Recovery Information System
  • RDF See “refuse derived fuel (RDF).”
  • rDNA Recombinant DNA.
  • RDV Reference dose values.
  • Reacher Reciprocating rake bar screen by Schloss Engineered Equipment.
  • reactant Any substance taking part in a chemical reaction.
  • reaction rate The rate at which a chemical reaction occurs.
  • reactivation The process of removing adsorbed organics and restoring the adsorp­tive characteristics of an adsorbent, usually by thermal or chemical means.
  • Reactivator® Solids contact clari.er by Graver Co.
  • reactive airways dysfunction syndrome (RADS) An asthma-like condition resulting in hyper-responsiveness to inhaled materials that may develop after long-term exposure to hydrogen sul.de.
  • reactive wall A permeable vertical wall constructed of a reactive mixture and installed below grade to treat groundwater that .ows through it.
  • reactive waste A solid waste that is normally unstable and readily undergoes violent change, generates toxic gases or fumes, or is capable of detonation or explosion.
  • reactivity The tendency for a chemical substance to combine with other elements and compounds.
  • reactor The container or tank in which a chemical or biological reaction is carried out.
  • Reactor-Thickener Sludge-thickening device using mixers and dewatering screens by JDV Equipment Corp.
  • React-pH™ pH-stable-activated carbon by Calgon Carbon Corp.
  • reaeration The absorption of oxygen into water under conditions of oxygen de.ciency.
  • reagent A chemical added to a system to bring about a chemical reaction.
  • reagent grade water High purity water suitable for use in making reagents for use in analytical procedures.
  • reasonable maximum exposure The maximum exposure reasonably expected to occur in a population.
  • reasonably available control measures (RACM) A broadly de.ned term refer­ring to technological and other measures for pollution control.
  • reasonably available control technology (RACT) Control technology that is reasonably available, technologically and economically feasible, and usually applied to existing sources in nonattainment areas; in most cases it is less stringent than new source performance standards.
  • reboiler An evaporator-condenser unit which produces secondary steam after con­densation of primary steam. Used to isolate steam systems and avoid cross contamination of boiler chemicals.
  • recalcining Recovery of lime from water or wastewater sludge, usually with a multiple hearth furnace.
  • recarbonation The reintroduction of carbon dioxide into water, usually during or after lime-soda softening.
  • receiving water Surface water body that receives ef.uent discharge from a waste­water treatment plant.
  • receptor A molecule that can selectively bind to another substance in the initial stages of a toxic response.
  • receptor cell A nerve ending or group of nerve endings specialized for the recep­tion of stimuli.
  • recharge The natural or arti.cial process of replenishing an aquifer.
  • recharge area A land area in which water reaches the zone of saturation from surface in.ltration.
  • recharge rate The quantity of water per unit of time that replenishes or re.lls an aquifer.
  • reciprocating rake bar screen An automatic bar screen with a single rake that is raised and lowered to clean a stationary bar rack.
  • reclaimed water Wastewater that has been treated to a level that allows for its reuse for a bene.cial purpose.
  • Recla-Mate® Modular physical chemical treatment plant by USFilter/Micro.oc.
  • reclamation The process of improving or restoring the condition of land or other material to a better or more useful state.
  • Recla-Pac Package biological treatment plant by USFilter/Micro.oc.
  • RECOjet Gas scrubber by USFilter/Gutling.
  • recombinant bacteria A microorganism whose genetic makeup has been altered by deliberate introduction of new genetic elements, and whose offspring also contain these new genetic elements.
  • recombinant DNA The new DNA formed by combining pieces of DNA from different organisms or cells.
  • recommended maximum contaminant level (RMCL) The maximum level of a contaminant in drinking water at which no known or anticipated adverse effect on human health would occur, including an adequate margin of safety. Rec­ommended levels are nonenforceable health goals. See also “maximum con­taminant level (MCL).”
  • reconstructed source Facility in which components are replaced to such an extent that the .xed capital cost of the new components exceed 50% of the capital cost of constructing a comparable brand new facility. New-source performance standards may be applied to sources
  • record of decision (ROD) A public document that explains which cleanup alter­native(s) will be used at National Priorities List sites.
  • recovery In reverse osmosis processes, recovery indicates the amount/percentage of product water recovered from the feed stream.
  • recovery rate Percentage of usable recycled materials that have been removed from the total amount of municipal solid waste generated in a speci.c area or by a speci.c business.
  • recreational waters Any waterbody used for recreational activities such as swim­ming, boating, or .shing.
  • Rectangulaire Package wastewater treatment unit formerly offered by USFil­ter/Envirex.
  • recycle ratio The recycled .ow rate divided by the in.uent .ow rate in an activated sludge wastewater treatment system or other process system.
  • recycling The process by which recovered materials are transformed into new products. See also “water recycling.”
  • red bag waste Medical or infectious wastes.
  • Red Fox Sewage treatment systems for marine applications by Red Fox Environ­mental, Inc.
  • Red List A list of 23 dangerous substances, designated by the U.K., whose dis­charge to the water should be minimized.
  • Red Rubber™ Bar screen toothed rake segments of cast urethane by Rubber Millers, Inc.
  • red tide A reddish discoloration of water caused by an excessive growth of certain microbes, whose toxins can cause massive .sh kills.
  • red water Water whose reddish color usually results from the precipitation of iron salts or the presence of microbes that depend on iron or manganese.
  • Red-B-Gone® Rust and iron stain remover by Pro Products, Corp.
  • redox potential See “oxidation-reduction potential (ORP).”
  • reducing agent Any substance that can give up electrons in a reaction.
  • reduction A chemical reaction where an element or compound gains electrons causing a decrease in valence.
  • Redux™ Dissolved air .otation system by ABS Pumps, Inc.
  • REECO® Product line of Dürr Environmental, Inc.
  • reed Any of a variety of tall, slender grasses grown in wet areas.
  • reed bed Tertiary wastewater treatment system where organics remaining in sec­ondary ef.uent are used as nutrients in the growth of reeds. Also used for biosolids volume reduction.
  • REEF® Fine pore .oor mounted diffuser by Environmental Dynamics Inc.
  • Reel Auggie® Sludge and compost mixer by Knight Manufacturing Corp.
  • ReelAer Horizontal cage surface aerator formerly offered by Walker Process Equipment.
  • reentry interval The period of time immediately following the application of a pesticide during which unprotected workers should not enter a .eld.
  • reference dose (RfD) The exposure level of a carcinogenic contaminant thought to be without signi.cant risk to humans when ingested daily over a speci.ed time period.
  • reformulated gasoline (RFG) Gasoline whose composition has been changed from conventional gasoline sold in 1990 to reduce air pollutants released from evaporation and exhaust emissions.
  • Refotex Fine bubble diffuser by Refractron Technologies Corp.
  • Refractite Ceramic .lter membrane by Refractron Technologies Corp.
  • refractory A highly heat resistant material used as a liner in a furnace or incinerator.
  • refractory organics Organic substances that are dif.cult or unable to be metab­olized in a biological system.
  • refrigerant A substance which, by undergoing a phase change, lowers the tem­perature of its environment. Commercial refrigerants, which include CFCs and HFCs, are liquids whose latent heat of vaporization results in cooling.
  • refueling emissions Emissions released during vehicle refueling.
  • refuse All solid waste material discarded as useless.
  • refuse derived fuel (RDF) Fuel produced from municipal solid waste through shredding, pyrolysis, or other methods.
  • refuse reclamation Conversion of solid waste into useful products, e.g., compost­ing organic wastes to make soil conditioners and separating aluminum and other metals for recycling.
  • Regal® Gas chlorinator by Chlorinators, Inc.
  • Regenair® Regenerative air blower by Gast Manufacturing, Inc.
  • regenerant A chemical solution used to restore the exchange capacity of ion exchange resin.
  • regenerate The process of restoring exchange capacity of an ion exchange material.
  • regenerative catalytic oxidizer (RCO) An emissions control device that utilizes a catalyst to accomplish VOC oxidation.
  • Regenerative Environmental Equipment Company Product line acquired by Dürr Environmental, Inc.
  • regenerative thermal oxidizer (RTO) An emissions control device that utilizes heat to accomplish VOC oxidation.
  • Re-Gensorb™ VOC and HAP removal system by M&W Industries, Inc.
  • Regional Administrator The administrative head of each of the ten regions orga­nized by the U.S. EPA.
  • Reg-U-Flo® Vortex valve .ow control device by H.I.L. Technology, Inc.
  • regulated asbestos-containing material (RACM) Friable asbestos material or nonfriable ACM that will be or has been subjected to sanding, grinding, cutting, or abrading or has crumbled, been pulverized, or reduced to powder in the course of demolition or renovation operations.
  • regulated medical waste Any solid waste generated in the diagnosis, treatment, immunization, or research of human beings or animals, or in the production or testing of related biological products.
  • Rehydro-Floc™ Aluminum chlorohydrate .occulant solution by Reheis, Inc.
  • reject The waste stream containing impurities rejected in a treatment process, most commonly applied to reverse osmosis, electrodialysis, and ultra.ltration systems.
  • reject staging Reverse osmosis process con.guration where the reject from one stage is used as feedwater on a subsequent stage to increase water recovery. Also called “brine staging.”
  • rejection In reverse osmosis, the percentage of dissolved solids removed from the feedwater as it passes through the semipermeable membrane. Also called “salt rejection.”
  • relative accuracy test audit (RATA) A comparison between an emissions stack tester’s readings and readings obtained from a CEM.
  • relative humidity The total amount of water vapor present in the air, expressed as a percentage of the maximum amount that the air could hold at a given temperature.
  • release Any occurrence where a regulated substance discharges, spills, pumps, pours, emits, injects, dumps, disposes, or escapes into the air, soil, or water.
  • Reliant™ Conventional package and modular .ltration product line by Roberts Filter Group.
  • REM Registered Environmental Manager.
  • rem Roentgen equivalent man. A measure of the effective radiation dose absorbed by human tissue.
  • remedial action The actual construction or implementation phase of a Superfund site cleanup that follows remedial design.
  • remedial investigation and feasibility study (RI/FS) An evaluation of the risks associated with a hazardous waste site that includes the process of selection of an appropriate remedy.
  • remedial response Long-term action that stops or substantially reduces a release or threat of a release of hazardous substances that is serious but not an immediate threat to public health.
  • remediation The treatment of waste to make it less toxic and/or less mobile, or to contain a site to minimize further release.
  • Remedi-Cat™ Catalytic oxidizer by Global Technologies.
  • REMS RCRA Enforcement Management System.
  • rendering plant A plant that converts grease and livestock carcasses into fats, oils, and other products.
  • renewable resource A resource that theoretically cannot be totally consumed due to its ability to reproduce or regenerate.
  • Renneburg Sludge dryer manufacturing division of Heyl & Patterson, Inc.
  • RenovAir™ Bio.ltration system for VOC reduction by Envirogen.
  • Reo-Pure Reverse osmosis system by Great Lakes International, Inc.
  • reportable quantity (RQ) Quantity of a hazardous substance that triggers reports under CERCLA. If a substance exceeds its RQ, the release must be reported to the National Response Center, the SERC, and community emergency coor­dinators for areas likely to be affected.
  • Reporter™ Multiprobe for measuring water conditions by Hydrolab Corp.
  • repowering Rebuilding and replacing major components of a power plant instead of building a new one.
  • representative sample A portion of material or water that is as nearly identical in content and consistency as possible to that in the larger body of material or water being sampled.
  • reserve capacity Extra treatment capacity built into solid waste and wastewater treatment plants and interceptor sewers to accommodate .ow increases due to future population growth.
  • reservoir An arti.cial or natural pond, lake, basin, or tank which is used to store or control water.
  • residence time The period of time that a volume of liquid remains in a tank or system.
  • residual Amount of a pollutant remaining in the environment after a natural or technological process has taken place, including the sludge remaining after initial wastewater treatment and the particulates remaining in air after it passes through a scrubbing or other treatment process.
  • residual chlorine See “chlorine residual.”
  • residual disinfectant concentration The concentration of a disinfectant after a stated contact time. See also “C × T.”
  • residual risk The extent of health risk from air pollutants remaining after appli­cation of the Maximum Achievable Control Technology (MACT).
  • residue Solid or semisolid material remaining after processing, evaporation, or incineration.
  • resin A material having ion exchange properties used in ion exchange systems.
  • resin beads Spherical beads with ion exchange properties used in ion exchange systems.
  • Resinator® Ion exchange system by Aqualogic Inc.
  • resistance (1) In water conditioning, the opposition offered by water to the .ow of electricity through which it may be used to estimate the mineral content; the reciprocal of electrical conductance. (2) For plants and animals, the inborn or acquired ability to withstand poor environmental conditions or attacks by chemicals or disease.
  • resistivity A measure of resistance to the .ow of electricity, used as an accurate measure of a water’s ionic purity.
  • Resi-Tech Division of Waterlink/Aero-Mod Systems.
  • Resolv-R2® Solvent recovery and waste disposal system by PBR Industries.
  • Resource Conservation and Recovery Act (RCRA) A 1976 U.S. law, amended in 1984, to regulate management and disposal of solid and hazardous wastes.
  • resource recovery The process of obtaining matter or energy from materials for­merly discarded.
  • respiration Intake of oxygen and discharge of carbon dioxide as a result of biological oxidation.
  • respirator Personal respiratory protection device certi.ed to meet minimum gov­ernment performance standards.
  • respirometer An instrument used to study the character and extent of respiration.
  • restoration Measures taken to return a site to pre-violation conditions.
  • Retec® Heavy metal recovery systems offered by USFilter/Industrial Wastewater Systems.
  • retentate The portion of the feed solution rejected by the membrane in a pressure-driven membrane process.
  • retention pond A basin used for wastewater treatment and/or storage.
  • retention time The length of time water or wastewater will be retained in a unit treatment process or facility.
  • Re-Therm® Thermal VOC oxidation unit by Dürr Environmental, Inc.
  • Retox™ Regenerative thermal oxidizer by Adwest Technologies, Inc.
  • retro.t Addition of a pollution control device on an existing facility without making major changes to the generating plant.
  • Retroliner Forms for .lter underdrain rehabilitation by Roberts Filter Group.
  • return activated sludge (RAS) Settled activated sludge that is returned to mix with raw or primary settled wastewater.
  • return sludge See “return activated sludge (RAS).”
  • reuse Using a product or component of municipal solid waste in its original form more than once.
  • reverse deionization A deionization system having an anion exchange resin ahead of a cation exchange resin.
  • reverse osmosis (RO) A method of separating water from dissolved salts by pass­ing feedwater through a semipermeable membrane at a pressure greater than the osmotic pressure caused by the dissolved salts.
  • reversible effect An effect which is not permanent; especially adverse effects which diminish when exposure to a toxic chemical is ceased.
  • Revolver™ Rotary adsorption system for VOC abatement and solvent recovery by Vara International.
  • Rex Water/wastewater equipment product line offered by USFilter/Envirex.
  • Rex Chainbelt Former name of USFilter/Envirex.
  • Reynolds number A nondimensional number that measures the state of turbu­lence in a .uid system. It is calculated as the ratio of inertia effects to viscous effect.
  • RF/AS Roughing .lter/activated sludge.
  • RfD See “reference dose (RFD).”
  • RFG See “reformulated gasoline (RFG).”
  • RFP Request for proposal.
  • RFQ Request for quotation.
  • RHA Rivers and Harbors Act.
  • rheology The study of the deformation and .ow of substances.
  • rhizosphere The zone of intermingled roots and soil.
  • RHRS Revised Hazard Ranking System
  • RI/FS See “remedial investigation and feasibility study (RI/FS).”
  • RibbonFlow™ Baf.ed clearwell by CBI Walker, Inc.
  • ribonucleic acid (RNA) One of two types of long-chain molecules containing hereditary material vital to reproduction.
  • Rich Tech Equipment product line by USFilter/Aerator Products.
  • Richards of Rockford Former equipment manufacturer acquired by Aqua-Aerobic Systems, Inc.
  • RIFS Remedial investigation and feasibility study.
  • rift A shallow, rapidly .owing and usually rocky area of water in a stream.
  • RIGA Former equipment manufacturer.
  • Riga-Sorb™ Activated carbon adsorbers by Farr Co.
  • right of free capture The concept that groundwater belongs to the person who owns the land above it and that he is free to capture and use as much as desired.
  • rill A small channel eroded into the soil surface by runoff which can be easily smoothed or obliterated by normal tillage.
  • Rim-Flo Peripheral feed, circular clari.er by USFilter/Envirex.
  • Ringelman test A method of quantifying the opacity of an air pollution emission by comparing it to a set of standard disks having increasing degrees of dis­coloration from light grey (number 1) through black (number 5).
  • Ringlace® Attached growth biomedia by Ringlace Products, Inc.
  • RingSparjer Air injection diffuser by Walker Process Equipment.
  • rinse The portion of an ion exchange regeneration cycle in which fresh water is used to remove spent and excess regenerant from the resin column.
  • Rio Linda® Chlorine dioxide generator by Vulcan Performance Chemicals.
  • rip rap Broken stone or rocks placed compactly or irregularly on dams, levees, dikes, or similar embankments for protection against the action of waves or currents.
  • riparian habitat Areas adjacent to rivers and streams with a high density, diver­sity, and productivity of plant and animal species relative to nearby uplands.
  • riparian rights A landowner’s rights to the water on or bordering his property, including the right to prevent diversion or misuse upstream.
  • Rippl diagram A graph which plots cumulative .ow versus time, and is used to design storage reservoirs and equalization basins.
  • rise rate See “over.ow rate (OFR).”
  • rising .lm evaporator An evaporator using vertical heat transfer surfaces where liquor on one side of the surface is boiled by steam condensing on the other side, causing vapors to rise carrying the liquid upward as a .lm.
  • risk A measure of the probability that damage to life, health, property, and/or the environment will occur as a result of a given hazard.
  • risk assessment Qualitative and quantitative evaluation of the risk posed to human health and/or the environment by the actual or potential presence and/or use of speci.c pollutants.
  • Risk Based Corrective Action (RBCA) A process using the principles of expo­sure assessment, toxicity, and mobility to make cost-effective corrective actions on sites while protecting human health and the environment.
  • risk based targeting The direction of resources to those areas identi.ed as having the highest potential or actual adverse effects on human health and/or the environment.
  • risk factor Characteristic (e.g., race, sex, age, obesity) or variable (e.g., smoking, occupational exposure level) associated with increased probability of a toxic effect.
  • risk management The process of evaluating and selecting alternative regulatory and nonregulatory responses to risk which requires the consideration of legal, economic, and behavioral factors.
  • risk speci.c dose The dose associated with a speci.ed risk level.
  • river basin The land area drained by a river and its tributaries.
  • RJ Environmental Former name of USFilter/RJ Environmental.
  • RKL® Pinch valve by Moyno Industrial Products.
  • RLL Rapid and large leakage
  • RM-10® Clay-based .occulating agent for wastewater by Colloid Environmental Technologies Co.
  • R-MAP Regional Management Assessment Program.
  • RMCL Recommended maximum contaminant level. This term is being discon­tinued in favor of “MCLG.”
  • RMP “Roberts Manhattan Process.”
  • RMP Risk management plan.
  • RMPR Risk Management Program Rule.
  • RMS™ Rinsewater maintenance system by USFilter/Industrial Wastewater Systems.
  • RNA See “ribonucleic acid (RNA).”
  • RO See “reverse osmosis (RO).”
  • Robo™ Bar screen by Vulcan Industries, Inc.
  • Robo Rover™ Traversing bar screen by Vulcan Industries, Inc.
  • Robo Stat™ Stationary bar screen by Vulcan Industries, Inc.
  • RoClean™ Membrane cleaners by Avista Technologies.
  • rodding A method of cleaning tubes or sewers using long rods which are able to remove or dislodge debris.
  • rodenticide A chemical or agent used to destroy rats or other rodent pests, or to prevent them from damaging food or crops.
  • RODTOX Rapid oxygen and toxicity tester by SAMI.
  • Roebelt Belt .lter press by Roediger Pittsburgh, Inc.
  • Roedos Mixing system for dry and liquid polymers by Roediger Pittsburgh, Inc.
  • Roe.lt Sieve drum concentrator by Roediger Pittsburgh, Inc.
  • Roe.ex Fine bubble diaphragm diffuser by Roediger Pittsburgh, Inc.
  • Roemix Lime post treatment mixing system for dewatered sludge by Roediger
  • Pittsburgh, Inc. roentgen Unit of exposure dose of X-ray or gamma radiation. Roepress Belt .lter press by Roediger Pittsburgh, Inc. Roevac Vacuum sewage system by Roediger Pittsburgh, Inc. Ro-Flo® Sliding vane compressor by A-C Compressor Corp. ROG Reactive organic gas. Rogun Reverse osmosis membrane cleaning solution by BetzDearborn-Argo District. RollAer Aerobic digestion aeration equipment by Walker Process Equipment. Roll-Dry Internally fed rotary .ne screen by Schlueter Co. Rolling Grit Aerated tank grit washing and removal unit by Walker Process Equip­
  • ment. Romembra Reverse osmosis membrane elements by Toray Industries, Inc. and Ropur AG (Europe). Romicon® Hollow .ber membrane .ltration products by Koch Membrane Sys­
  • tems, Inc. Romi-Kon™ Oil/water emulsion separator by Koch Membrane Systems, Inc. RomiPure™ Hollow .ber ultra.ltration products by Koch Membrane Systems,
  • Inc. Roots Centrifugal compressor and blower product line by Dresser Industries/Roots
  • Division. Roplex Live bottom feeder for solids and storage piles by Hindon Corp. Roptic® Filter cake sensor by Rosenmund. RoQuest™ Reverse osmosis coagulants and .occulants by Avista Technologies. Rosep™ Reverse osmosis systems by Graver Co. Rossmark Former name of USFilter/Rossmark. Rotadisc® Sludge dryer by Atlas-Stord, Inc. Rota.lt® Wastewater fabric .lter by Hans Huber GmbH. Rota.ne Rotary .ne screen by Waste-Tech, Inc. Rotamat® Screening equipment product line by Lakeside Equipment Corp. (U.S.)
  • and Hans Huber GmbH (Europe). rotameter A variable area liquid .ow meter. Rotamix Digester mixing system combining chopper pumps and mixing nozzles
  • by Vaughan Co., Inc. Rotapak Screw type screenings compactor by Longwood Engineering Co., Ltd. Rota-Rake Circular sludge collector by Graver Co. Rotarc Arc-type bar screen by John Meunier, Inc. rotary collector Rotating mechanisms used in circular clari.ers to collect and
  • remove settled solids. rotary distributor Rotating pipe that evenly distributes wastewater on the surface of a trickling .lter.
  • rotary drum screen Cylindrical screen used to remove .oatable and suspended
  • solids. rotary drum thickener Rotating cylindrical screen used to thicken sludge. rotary kiln incinerator An incinerator consisting of a slowly rotating, long hor­
  • izontal cylinder in which material is fed at one end and tumbled by the kiln
  • to promote drying as it is conveyed to the other end. Rotasieve Externally fed rotary .ne screen by Waste-Tech, Inc. rotating biological contactor (RBC) A .xed .lm biological treatment device
  • where biological organisms are grown on circular discs and mounted on a horizontal shaft that slowly rotates through wastewater. rotavirus An enteric virus commonly found in domestic wastewater which causes
  • diarrhea. Rotex Rotating grit removal system by Simon-Hartley, Ltd. Rotho® Hose pump by USFilter/Wallace & Tiernan. rotifer A very small aerobic, multicellular animal that feeds on organic matter in
  • wastewater. Rotoair Disc Submerged rotating biological contactor by Pro-Equipment, Inc. Rotobelt In-channel .ne screen by Dontech, Inc. Roto-Brush Rotary screen brush cleaning device by Dontech, Inc. Roto-Channel Combination bar screen and compacting conveyor by Dontech, Inc. RotoClean Screenings washer by Parkson Corp. RotoClear Microscreen formerly offered by Walker Process Equipment. Rotoco® Continuous duty granular media .lter by Baker Process. RotoDip Manually controlled slotted pipe skimmer by Walker Process Equipment. Rotodip® Volumetric feeder for liquids or slurries by BIF. Rotodisintegrator Debris grinder by USFilter/Zimpro. Roto-Drum Internally fed rotary .ne screen and thickener by Dontech, Inc. Roto-Guard® Horizontal drum screen/thickener by Parkson Corp. Roto-Kone® Gravity belt thickener drainage elements by Komline-Sanderson
  • Engineering Corp. Rotoline Rotary distributor for trickling .lter formerly offered by USFil­
  • ter/Envirex. Rotomite Sludge handling dredger by SRS Crisafulli, Inc. Rotopac® Screw type screenings compactor by John Meunier, Inc. Rotopass Externally fed rotary .ne screen by Passavant-Roediger GmbH. Roto-Press Combination rotary .ne screen and dewatering press by Dontech, Inc. Roto-Press Screenings compactor by Roto-Sieve AB. RotoPress® Screenings compactor by Parkson Corp. Rotopress® Shaftless screw compactor by Andritz-Ruthner, Inc. rotor See “brush aerator.” Rotordisk® Rotating biological contactor by CMS Group, Inc. Rotorobic Package rotating biological contactor system by Waterlink Separations,
  • Inc. Rotoscoop® Self-cleaning volumetric feeder by Wyssmont Co., Inc. Roto-Scour Sand .lter underdrain system by Graver Co. Rotoscreen In-channel bar screen by Waterlink Separations, Inc.
  • RotoSeal Rotary distributor for trickling .lters by Walker Process Equipment.
  • Roto-Sep™ Primary wastewater treatment system by Dontech, Inc.
  • Rotoshear Internally fed rotary .ne screen by Waterlink Separations, Inc.
  • Roto-Sieve® Internally fed rotary .ne screen by Roto-Sieve AB.
  • Roto-Skim Rotary pipe skimmer by USFilter/Envirex.
  • Rotosludge® Drum-type rotary sludge thickener by Waterlink Separations, Inc.
  • RotoSorb VOC/HAP concentrator by Waterlink/Barnebey Sutcliffe.
  • Rotospir® Shaftless screw conveyor by Andritz-Ruthner, Inc.
  • Rotostep In-channel bar screen by Waterlink Separations, Inc.
  • Rotostrainer Externally fed rotary .ne screen by Waterlink Separations, Inc.
  • Rotosweep Filter media surface agitator by Roberts Filter Group.
  • Rototherm® Agitated thin .lm evaporator by Artisan Industries, Inc.
  • Roto-Thickener™ Rotary drum sludge thickener by Dontech, Inc.
  • Roto-Trak Sludge plows or chicanes used with gravity sludge dewatering by Komline-Sanderson Engineering Corp.
  • Roto-Trols Pressure operated pump controller by Healy-Ruff Co.
  • Rotox Submersible aeration and mixing system by USFilter/Davis Process.
  • rough .sh Fish not prized for eating, such as gar and suckers, which are usually more tolerant of changing environmental conditions than game species.
  • roughing .lter A high-rate .lter designed to receive high hydraulic or organic loading rates as a .rst, or intermediate, treatment step.
  • route of exposure The avenue by which a chemical comes into contact with an organism, and which may include inhalation, ingestion, dermal contact, or injection.
  • ROV Remotely operated vehicle.
  • Rover Rust removing compounds by Hach Co.
  • ROWPU Reverse osmosis water puri.cation unit.
  • Roxidizer® VOC and air toxics control system by Tellkamp Systems, Inc.
  • Royce Equipment Screening and equipment manufacturer acquired by USFil-ter/Rex & Link-Belt Products.
  • ROZ3 Catalyst-impregnated activated carbon by Norit Americas Inc.
  • rpm Revolutions per minute.
  • RQ See “reportable quantity (RQ).”
  • RSD Risk-speci.c dose.
  • RSDS Vacuum-assisted rapid sludge dewatering system by the U.S. Environmental Products, Inc.
  • RSI See “Ryznar Stability Index (RSI).”
  • RSPA Research and Special Programs Administration of U.S. Department of Transportation.
  • RTECS Registry of Toxic Effects of Chemical Substances.
  • RTI Evaporator Wastewater evaporator product line acquired by USFilter/Dewa­tering Systems.
  • RTO See “regenerative thermal oxidizer (RTO).”
  • RTR Reinforced thermosetting resin.
  • rubbish Combustible and noncombustible solid waste from residential and com­mercial sources.
  • run The time period or continuous course during which a unit operates or a test occurs.
  • rundown screen See “static screen.”
  • running losses Evaporation of motor vehicle fuels from a fuel tank while a vehicle is in use.
  • runoff Rainwater, leachate, or other liquid that drains over land and reaches a drain, sewer, or body of water.
  • RUP Restricted use pesticide.
  • rupture disk A diaphragm designed to burst at a predetermined pressure differential.
  • RWH Restricted hazardous waste.
  • Ryznar Stability Index (RSI) A scale used to evaluate the corrosion or scaling potential of water


A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z