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 ABSORPTION: Assimilation  of  molecules  or  other  substances into  the  physical  structure  of  a  liquid or solid without chemical reaction.

 ACID:  A solution with a pH value less than 7.

 ACTIVATED  CARBON:  Carbon  that  has  undergone a  process of activation which greatly   increases  its surface area and therefore sites for adsorption.  It is not unusual to have over 3,000 square feet of  surface per gram of carbon.  Its uses in water treatment are many, including the adsorption of taste, odor,  and color.  A laboratory use is for the concentration of organic matter for waste treatment analysis.

 ACTIVATED  SILICA:  Sodium silicate that has been systematically precipitated by reducing the pH to below 9, usually by chlorine.

 ACTIVATED  SLUDGE:  A  process of secondary waste treatment designed to encourage growth of  aerobic bacteria by forcing large quantities of air through the waste and recycling viable bacteria to the incoming waste.

 ADSORPTION:  Physical adhesion of molecules or colloids to the surface of solids without chemical reaction.

 AERATE,  AERATION:  To  impregnate or saturate water or waste with air.  Ferrous iron removal, flotation, encouraging aerobic bacteria  in  waste  treatment and carbon dioxide removal are its major purposes.

 AEROBIC ORGANISM:  An organism, usually in reference to bacteria, that thrives in the presence of oxygen.

 AGGLOMERATE:  To  gather fine particulates together into a larger mass.

 ALGAE:  Simple plants, often microscopic, usually aquatic.

 ALGAECIDE:  A chemical highly toxic to algae, such as copper sulfate, preferably having selective toxicity in the proper concentration for algae with negligible toxicity for other forms of life.

 ALKALINITY:  Generally considered the bicarbonate, carbonate and hydroxide contents, although other materials contribute.

 AMPHOTERIC:  Capable of reacting in water either as a weak acid  or as a weak base.  For example, aluminum salts hydrolyze in water to produce a compound that may be considered a weak base, or a weak acid.  A property of certain oxides makes them reactive both with acids and bases.

 ANAEROBIC ORGANISM:  An organism, usually in reference to bacteria, that thrives in the absence of oxygen.

 ANION:  A negatively charged ion resulting from dissociation of salts, acids, or alkalis in aqueous solution.

 ANIONIC:  The condition of a polymer, colloid, or large particle having exchangeable cations on its surface and an opposite, negative charge on the substrate.

 ANODE:   In electrolysis or electrochemical corrosion, a site where metal goes into solution as a cation leaving behind an equivalent number of electrons to be transferred to an opposite electrode, called a cathode.

 ANODIZING:  The treatment of a metal surface whereby the metal is made anodic.

 API  GRAVITY:  An index of specific gravity defined by the American Petroleum Institute.

 API  SEPARATOR:  A simple gravity separator meeting the design standards of the American Petroleum Institute for separation of oil and solids from wastewater.

 AQUIFER:  A  porous, subsurface geological structure carrying or holding water, such as a well.

 ASBESTOS:  Insulation from mineral asbestos.  Frequently used in ceiling and high temperature insulation.

 AUTOTROPHIC ORGANISM:  An organism capable of consuming inorganic matter and converting it to organic matter.


 BASE:  A solution with a pH value higher than 7.

 BAT:  Best Available Technology economically achievable 

 BAUXITE:  The raw material for aluminum sulfate manufacture

 BCT:  Best  Control  Technology, regardless of cost.

 BIOCIDE:  A chemical used to control the population of troublesome microbes.

 BIOLOGICAL  MATERIALS:  Biological materials which may be present in waste streams including: dissolved solids, coliform bacteria (BOD and COD)

 BIOTA:  All living organism of a specified region.

 BLOOM,  ALGAE  BLOOM:  A readily visible concentration of algae growth usually occurring in the  absence of an algaecide when weather, sunlight and nutrient conditions favor a logarithmic phase of growth.

 BOD:  Biological Oxygen Demand.  The amount of oxygen required by  bacteria to destroy organic  material present in the wastewater.

 BOD LOAD FOR TRICKLING FILTER:  Pounds of  BOD per day, in waste applied, per 1,000 cubic feet of filter volume

 BOD  PERCENT  REDUCTION: The  percent  BOD is reduced through treatment.  It is a useful figure in the calculation of waste plant efficiency if not misused.

 BPT:  Best Practical Technology currently available

 BREAK-POINT CHLORINATION:  An extremely effective technique in controlling  bacteria, taste and odor.  The chlorine dose is increased with an accompanying increase in combined residual to a point where the residual abruptly drops.  This is called the break-point where combined chlorine is broken apart by further oxidation releasing free nitrogen and other gases.  As the chlorine dose is increased,   the residual will increase proportionately as free chlorine.

 BROWNIAN  MOVEMENT:  The  bombardment of colloidal particles by molecules of the dispersing  medium which keeps the colloid agitated and suspended indefinitely.

 BS  &  W:  (Bottom sediment and water).  A measure of oil quality based on the volume percent of sediment and water that can be centrifuged from a sample.

 BUFFER:  A substance in solution which accepts hydrogen ions or hydroxyl ions added to  the solution as acids or alkalis, minimizing a change in pH.


 CALCITE:  A high purity form of calcium carbonate.

 CAKE:  A term applied to a dewatered residue from a filter, centrifuge or other dewatering device.

 CARBONATE   HARDNESS:  That hardness in a water caused by bicarbonates and carbonates of calcium and magnesium.  If alkalinity exceeds total hardness, all  hardness is carbonate hardness;  if hardness exceeds alkalinity, the carbonate hardness equals the alkalinity.

CARBON  DIOXIDE:  A compound that has a great effect on water treatment.  It is often a major factor affecting alkalinity, buffer capacity, stability, corrosion,  floc settling, filter gassing and a host of minor effects.

CARRYOVER  -  PIN  POINT  CARRYOVER:  That part of the floc that has not flocculated to settleable  size or has been mechanically sheared or torn up so that it carries over and settles on the filters.  It is a measure of coagulation and mechanical flocculation efficiency.

CATALYSIS:  Addition of a material (catalyst) that does not take a direct part in a chemical reaction but increases the rate of the reaction.

CATION:  A positively charged ion resulting from dissociation of molecules in solution.

CATIONIC:  The condition of a polymer, colloid or large particle having exchangeable anions on its  surface and an opposite, positive charge on the substrate.

CAUSTIC SODA:  A common water treatment chemical, sodium hydroxide (lye).

CHELATING  AGENTS:  Organic compounds having the ability to withdraw ions from their water solutions into soluble complexes.

CHLORAMINE:  Combined chlorine formed by the reaction of ammonia.  These are reported to be effective bactericides although have a slower rate of kill.  They are used where difficulty is experienced  in maintaining a free chlorine residual and occasionally where phenolic taste makes chlorine undesirable    due to the resulting chlorophenol taste.  Chloramines are also formed by reaction with nitrogenous portions of the chlorine demand.

CHLORINE:  An  element widely used in water and waste treatment for disinfection and sterilization; a valuable oxidizing agent. It is a greenish gas under normal conditions, choking and highly toxic on inhalation.

CHLORINE  DIOXIDE:  A powerful oxidizing agent.  It is unstable and is produced in water and waste plants by adding sodium chlorite  (not  chloride)  to  raw  water containing an excess of chlorine.  Caution: reacts violently with most organic material.

CHLORINE  FREE:  Chlorine in solution uncombined or unreacted with  other materials.  This can obviously be obtained only after the entire chlorine demand has been satisfied.  This is the most effective  bactericidal state.  It is common practice to refer to chlorine, hypochlorous acid and hypochlorite as free chlorine residual.

CLEAN  WATER  ORGANISMS:  The association or ecological balance of  many  species  that  are  found in an unpolluted environment.  Attempts are made to use these as a measure of pollution.  The same is true of polluted water organisms.

COAGULANT,  COAGULATION:  A coagulant is a substance which when added to a colloidal dispersion destabilizes the dispersion by neutralizing the charges on the particles, usually negative, causing the colloidal particles to collide and agglomerate into larger  particles.  The term coagulation is the name for this process.

COAGULANT AID:  Any material that substantially aids coagulation and/or flocculation but which would not function as a coagulant alone.  Such materials are usually highly selective, and the dose is critical depending upon raw water conditions.  They are widely diverse compounds, a few of which are clays, agar, gelatin,  sodium silicate (activated silica) synthetic polymers and natural or modified starch.

COD:  Chemical  Oxygen Demand.  A test that measures the amount of  the total organic matter in a waste that can be oxidized by a strong oxidizing agent,  current  potassium  dichromate,  with silver  sulfate as a catalyst under acid conditions.  There is seldom a direct correlation with BOD.

COLIFORM:  A bacteria group used as an indicator of fecal contamination.  Except for special cases they are considered benign.  A positive test indicate the possibility of the presence of enteric pathogens,   disease germs originating in the intestine.

COLLOID,  COLLOIDAL:  Small solid particles dispersed in a water medium is the class of colloidal dispersion normally dealt with in water and waste treatment.  The particle size is from 1 to  100 millimicrons, although the actual size may be open to argument, especially at the smaller end of the scale.  The particles are charged and exhibit Brownian Movement and the Tyndall Effect.

CONCENTRATION:  The process of increasing the dissolved solids per unit volume of solution, usually  by evaporation of the liquid;  also the amount of material dissolved in a unit volume of solution.

CONDUCTIVITY:  The ability of a substance to conduct heat or electricity.  Electrical conductivity is usually expressed in microsiemans per centimeter.

CONSISTENCY:  In the pulp/paper industry, a term for the density in percent by weight dry matter, of a slurry of pulp.

CONTAMINANT:  Any foreign  component present in another substance.

COPPERAS:  An industrial by-product varying between manufacturers in chemical content, impurities and  physical properties.  The  iron content is bivalent.  Its use by mistake instead of ferric sulfate could be harmful, since if not fully oxidized to the ferric state it will carry through to the finished water.  Both ferrous and ferric sulfates can be called iron sulfate in generic terminology.

COPPERAS  CHLORINATED  Ferrous sulfate oxidized with chlorine in order to function as a coagulant. Theoretically, one pound of chlorine is required to oxidize eight pounds of copperas.  In practice,     an excess of chlorine is needed.  If the copperas is not totally oxidized, soluble ferrous iron will carry through to the finished water.

COPPER  SULFATE:  Cupric  sulfate, bluestone.  Its major use in water treatment is as an algaecide.

CORROSION:  A  term usually used in reference to metals.  It is the  result of a chemical or galvanic reaction in which the metal is solubilized or changed to a soluble metal salt thereby losing weight and  being weakened.  Where iron is corroded in finished water, the solubilized iron result in water quality problems.

CRACKING:  An oil-refining process that breaks large molecules into smaller ones.


DEINKING:  The process of removing ink from secondary fibers.

DEIONIZATION:  Any process removing ions from water, but most commonly an ion exchange process where cations and anions are removed independently by each other.

DEMINERALIZATION:  Any process used to remove minerals from water;  however, commonly the term is restricted to ion exchange processes.

DESALINATION:  The removal of inorganic dissolved solids from water.

DESALTING:  The removal of salt from crude oil.

DETACKIFY:  Treatment of solids from a paint spray booth to eliminate their sticky properties.

DETENTION  TIME:  The time retained in a treatment plant or a specific portion of the plant.

DETERGENTS:  Sulfanated neutralized products of aliphatic and aromatic hydrocarbons.  Newer detergents are biodegradable.

DEWATER:  To separate water from sludge to produce a cake that can be handled as a solid.

DIALYSIS:  A separation process that depends on differences in diffusion rates of solutes across a permeable membrane.

DIATOMS:  Organisms related to algae, having a brown pigmentation and a siliceous skeleton.

DIGESTION, DIGESTER:  A term generally used to describe a process of anaerobic decomposition of  putrifiable solids to methane and carbon dioxide.  Total detention time is reported to be  from 10 to 30 days to two to three months.  Sometimes aerobic digestion is used.

DILUTION  FACTOR:  The effect of a large volume of liquid dilution.  Waste Treatment  - The effect of a given volume and strength of waste when dispersed in a receiving body of water.  As an example, total treatment may be necessary during low flow stream conditions, but little or none necessary during flood stage.  Water Treatment - Usually used in reference to chemical feed.  A chemical may be corrosive in a concentrated solution but have no corrosive effect at all when diluted by the raw water.  Sometimes it is used to refer to free water source to below  the problem threshold.  This is often the case in wells or well and surface combinations.

DISINFECTION:  To free from infectious, disease producing or harmful microorganisms

DISPERSANT:  A chemical which causes particulates in a water system to remain in suspension.

DISSOLVED  OXYGEN:  Oxygen dissolved in system above requirements for BOD and COD.  Measure of water quality.

DISSOLVED  SOLIDS: D.S.  Technically any material that has been dissolved        becoming a true solution.  Finely divided and colloidal solids sometime are  reported as D.S. or  total dissolved solids  T.D.S.  These are more correctly included as suspended solids, although State Health Department procedures usually are followed.

DMR:  Discharge Monitoring Reports.

DOMESTIC WATER WASTE:  Sewage from homes without industrial contaminants.

DOT:  Department of Transportation.


ECOLOGY:  The science of the interrelations between living organisms and their total environment.

ELUTION:  The process of extracting one solid from another.  Often used incorrectly to describe the regeneration of an ion exchanger


ELUTRIATION:  A waste treatment term. The washing of sludge to remove soluble materials which may inhibit coagulation and compacting which reduces the final volume of sludge.

EMULSION: A colloidal dispersion of one liquid in another.

ENTRAINMENT:  The transport of water into a gas stream.  In a boiler, this is a carryover, in a cooling tower, drift.

ENVIRONMENT:  The sum of all external influences and conditions affecting the life and development of an organism.  Total environment is a  redundant  term  used to emphasize the effect of slight and often momentary changes usually induced by man.

EPA:  Environmental Protection Agency.  Formed in 1970.  Administers 9 Federal Environmental Laws: CAA            - Clean Air Act

CWA           - Clean Water Act

SDWA         - Safe Drinking Water Act

CERCLA     - Comprehensive Environmental Response Compensation and Liability Act (SUPERFUND)

RCRA          - Resource Conservation & Recovery Act

IFRA          - Federal Insecticide, Fungicide & Rodenticide Act

MPRSA        - Marine Protection Research & Sanctuaries Act

UMTRCA     - Uranium Mill Tailings Radiation Control Act

TSCA           -Toxic Substances Control Act

 EUTROPHICATION:  Nutrient enrichment of water.  Euthrophic waters support rich organic production  such as algae blooms.  The term is sometimes used to describe the mechanism causing the filling of a lake with solid wastes.


 FACULTATIVE BACTERIA:  Bacteria able to grow under either aerobic or anaerobic conditions.  Facultative  erobes are fundamentally aerobic but can grow or even thrive in the absence of oxygen.  A facultative anaerobe is anaerobic but can grow in the presence of oxygen.

 FAT:  Basically insoluble animal fat.

FAUNA:  The entire animal life of a specific region.

FDA:  Food & Drug Administration.

FERRIC CHLORIDE:  A trivalent iron coagulant and sludge conditioner.       Its water treatment use is limited by its corrosiveness even to stainless steel and toxicity to handling personnel when putting it into solution.

FERRIC HYDROXIDE:  The end product and floc former resulting from the use of ferric iron coagulants.  In natural water the floc is composed of complex chemicals including ferric hydroxide, but the chemical  characteristics are analogous.  Ferric hydroxide is insoluble at all normal pH's encountered in water and waste treatment since it is non-amphoteric.

FERRIC SULFATE:  A widely used coagulant and sludge conditioner which tolerates a wide range of pH and turbidity conditions.  The contained iron is in the trivalent state, and is therefore a coagulant without further oxidation.

FFDCA: Federal  Food  & Drug & Cosmetics Act - responsible for pesticides in food.

FILTER AID: Similar to coagulant aids but added to water prior to filtration.  Their purpose appears to be to produce an artificial or synthetic “schmutzdecke” to improve the efficiency of filtration.  They have proven useful with filters in poor condition in which particulate migration or breakthrough occur.  They are also recommended for some high rate filters.

FILTERS,  ANTHRACITE,  ANTHRAFILT:  It is graded similarly to a sand filter, but is considerably  coarser and lighter.  It requires less backwash pressure, but the coarseness (0.72mm) sometimes allow particulate and   bacterial migration or breakthrough requiring frequent backwashing.

 FILTER, CAPPED:  A portion of the top level of a sand filter is replaced with anthracite media.  This gives longer filter runs with the safety of sand filters.  Results have generally been good.

 FILTER, HIGH RATE:  An apparently successful attempt to increase the rate of sand filtration and utilization of the entire bed rather than the top four to eight inches.  The media is graded by density so the large media is on the surface with the particle size decreasing with depth.  It is relatively new, but excellent results have been observed.

 FILTER,  LABORATORY:  The choice of filters and methods will depend on the size of the particulate matter to be removed or the size or amount of particles that can be tolerated in the filtrate.  Ordinary laboratory filter papers vary widely in the porosity.  Usually the higher the number designating the paper, the smaller the particle it will remove.

 FILTER PRESSURES:  Mainly used in industrial water treatment, but occasionally found in municipal treatment plants.  It is a filter entirely enclosed in a metal tank except for inlet and outlet connections.  The media varies widely.

 FILTER, RAPID SAND:  The filter media is sand graded by size with the smallest size being on the surface.  The normal filter rate is approximately 2  gal./min./sq. ft. before loss of head and backwash.  It is reported that only the top four to eight inches is utilized.

 FILTRATE:  The liquid remaining after removal of solids as a cake in a filter.

 FILTRATION:  The process of separating solids from liquids by porous substance through which only the liquid means  of  a passes.

 FLASH:  The portion of a superheated fluid converted to vapor when its pressure is reduced.

 FLASH MIX, FAST MIX:  This stage along with accurate chemical feed  is the heart of every water plant and waste plant utilizing coagulation.  The coagulant  must be completely mixed with the raw water or waste within seconds to obtain optimum results from coagulation.

 FLOC:  Turbidity or particulate matter that has been agglomerated.  Whether particulate agglomeration has proceeded enough to be called a floc is a matter of individual judgment.

 FLOCCULATION:  The process of agglomerating or building of the macrofloc that resulted from coagulation into large agglomerates until the shear force of  water movement prevents further building or  until it settles out.  There is academic argument over the mechanisms, however it is generally held that the greatest effects on flocculation are caused by the quality of the earlier chemical coagulation stage, and from that point the mechanical efficiency designed into the plant; therefore, flocculation in basically a mechanical process.

 FLOCCULATOR:  That portion of a water or waste plant following the flash mix but prior to settling.    The purpose of the flocculator in to gently agitate the macrofloc from the flash mix giving it the opportunity to build larger without shearing or tearing up the floc in any way.  This non-shearing requirement is ignored in some plant designs resulting in poor efficiency, high chemical costs, short filter runs and marginal quality finished effluent.

 FLORA:  The entire plant life of a specific region.

 FLOTATION:  A process of separating solids from water by developing a froth in a vessel in such fashion that the solids attach to air particles and float to the surface for collection.

 FLUORIDATION:  The addition of small quantities of a fluoride to potable water to bring the maximum fluoride content to the usually  recommended  level  of  1.0 to 11 mg/L.  Fluoridation is for the reduction of dental cavities in children.

 FOG:  Fats,  Oils, and  Grease.  Includes:  Hydrocarbons, fatty acids, soaps, fats and waxes whose content is determined by freon extraction of the sample and infrared analysis of the extract.  The method  includes both suspended and dissolved substances.  Usually the dissolved substances cannot be removed by mechanical means.

 FUEL OIL:  Generic term for hydrocarbon fuels.

 FUNGI:  As applied to water, simple, one-celled animals without chlorophyll, often filamentous.  Molds and Yeasts are included in this category.

 FWPCA:  Federal Water Pollution Control Act.


 GALVANIC  COUPLE:  The connection of two dissimilar metals in an electrolyte that results in current flow through the circuit.

 GANG MIXER:  Multiple unit stirrer.

 GPM:  Gallons Per Minute of a flowing stream.

 GRAINS PER GALLON:  A unit of concentration.  lgr/gal = 17.1 mg/L.

 GREASE:  Compounded solid lubricant - contains petroleum base oil, animal fats, soaps (usually sodium, calcium, lithium), special chemicals.

 GRIT, GRIT CHAMBER:  In waste treatment, a chamber ahead of primary settling to remove sand,  gravel and larger inorganic matter.  They are desirable on all waste treatment plants and almost a  necessity where there are cross connections between storm and sanitary sewers.

 GROUND WATER:  Water beneath ground surface.


 HARDNESS:  The  concentration of calcium and magnesium salts in water.  Hardness is a term originally  referring to the soap-consuming power of  water; as such  it is sometimes also taken  to include iron and manganese.  A looser definition is any cation or anion that is capable of reacting with soap to form precipitates, curds or scale.

 HARD   WATER:  The  measurement of the amount of divalent metallic ions contained by a water.  Soft  0 to 75 mg/L.  Moderate   75 to 150 mg/L.  Hard 150 to 300 mg/L.  Very Hard over 300 mg/L.

HAZARDOUS  WASTE:  Waste which is listed by the EPA as being a danger to human health or the environment.  Also includes waste which may not be listed but has one or more of the following characteristics:  it is ignitable, it is corrosive, or it reacts violently with water or other materials.

HAZARDOUS  WASTE  LABEL:  Labeling a waste containment showing content and date collected.

HERBICIDE:  Chemicals intended to kill plant life, can be selective or general.

HUMIDIFICATION:  The addition of water vapor to air.

HYDRAULIC LOAD:  The gallons of flow per day per square foot of filter surface area.  The use of metric measurement is also accepted.

HYDROPHILIC:  Having an affinity for water.  Its opposite, non-water-wettable, is hydrophobic.

HYPOLINNION:  That region of a body of water that extends from the bottom up to the thermocline.    This region is the most removed from surface influence and is likely to have chemical reducing  conditions and to concentrate nuisance materials such as manganese and taste.


IGNITABLE WASTE:  Combustible or flammable materials; paints, solvents, oils, etc.

INCOMPATIBLE WASTE:  Waste that reacts with other materials or water.

INDICATOR  ORGANISMS:  An organism found only under certain conditions (usually used regarding pollution), or in the absence of  certain conditions.  Equating pollution to specific organisms is  useful,  although a better correlation is made by observation of the ecological balance.

INDUSTRIAL WASTE WATER:  Water containing any type of industrial contaminants as well as sanitary sewage.

INFILTRATION:  Inleakage of groundwater into sewage piping.

ION:  An atom or molecule that has lost or gained one or more electrons.  Through this ionization it  becomes electrically charged.

ION EXCHANGE:  A process by which certain undesired ions of given charge are absorbed from solution within an ion-permeable absorbent, being replaced in the solution by desirable ions of similar charge from the absorbent.

IONIC STRENGTH:  A measure of the strength of a solution based on both the concentrations and valences of the ions present.

IONIZATION:  The dissociation of a molecule into atoms or groups of atoms.  This occurs when salts are dissolved in water.  As an example, when copper sulfate is dissolved in water, the solution contains positive copper ions and negative sulfate ions.

IRRIGATION:  Land application for disposal of effluents.


LIME:  A common water treatment chemical.  Limestone is burned to product quicklime, which is mixed  with water to produce slaked, or hydrated lime.

LIMESTONE:  A rock containing mainly calcium carbonate and impurities.

LIMESTONE, DOLOMITIC:  Limestone containing both calcium carbonate and magnesium carbonate.

LOTIC ENVIRONMENT:  Running water such as rivers.

LUBE  OIL:  Special crude fraction for viscosity - contains up to 50% chemical blending materials.

MACROFLOC:  The stage of flocculation when the floc grows large enough to be seen.

MICRO-ORGANISM:  An organism visible to the unaided eye.

MACROSCOPIC:  Large enough to be seen by the unaided eye.

MCL:  Maximum Contaminant Level of pollution in drinking water.

MEMBRANE:  A barrier, usually thin, that permits the passage only of particles up to certain size or special nature.

METALS:  Limitations have been placed on the quantities of metals that can be discharged from treating   plants. Specification are not always consistent nor are they the same for every operation.  A processor must analyze his process for compliance.  List of metals with restrictions:

         Aluminum                 Cadmium                    Manganese

         Arsenic                     Chlorine                     Nickel

         Ammonia                  Copper                       Nitrates

         Antimony                  Cyanide                      Phosphorus

         Barium                     Chlorides                    Selenium

         Beryllium                  Fluoride.                     Silver

         Bromide                   Iron                           Sulfide.

         Bromates                  Lead                         Zinc

         Boron                      Mercury

MF:  Membrane Filter - a bacterial count method.

MG/LITER:  Milligrams of a substance contained or dissolved in 1,000 liters  of  solution  (usually water).  Equivalent to parts per million.

MICROORGANISM:  Any organism small enough to be invisible or indistinguishable to the unaided eye.   Some authorities hold that they are only those organisms that can be seen with a microscope.

MINERAL:  Any inorganic or fossilized organic material having a definite chemical composition and structure found in a natural state.

MIXING  ZONE:  Waste water effluent to streams, lakes, canals, etc.  Must be properly mixed with existing water and meet specifications set for location.

MPN:  Most Probable Number - a bacterial count method.


NATIONAL  RESPONSE  CENTER:  Place to call in case of spill (800) 424-8802.  Failure to do so may result in jail sentence and fine.

NCP:  National Contingency Plan  -  guide for Superfund activity.

NEMATODES:  Any of a class or phylum Nematoda, unsegmented roundworms or threadworms.  They live as parasites or live free in soil and water.  Many have a high tolerance for chlorine, thereby protecting some ingested bacteria and virus.

NESHAPS:  National Emissions Standards for Hazardous Pollutants - very hazardous materials, small quantities.

NEUTRALIZATION:  Most commonly, a chemical reaction that produces a resulting environment that is  neither acidic nor alkaline.  Also, the addition of a scavenger chemical to an aqueous system in excess concentration to eliminate a corrosive factor, such as dissolved oxygen.

NONCARBONATE HARDNESS:  Hardness in water caused by chlorides, sulfates and nitrates of calcium and magnesium.

NOTIFICATION OF HAZARDOUS WASTE ACTIVITY FORM:  EPA-8700-12(85) -  An application for EPA number.  Covers hazardous waste accumulated.

NPDES  PERMIT:  The  National  Pollution  Discharge Elimination System permit required by and issued by EPA.

NUTRIENTS:  Nutrient discharges are limited for many waste stream discharges.  This is especially true  for  nitrogen, phosphorus and potash that may enter streams or lakes.  List of nutrients: total nitrogen, total phosphorus and total potassium.


OCCLUSION:  An absorption process by which one solid material adheres strongly to another, sometimes occurring by coprecipitation.

OIL:  Generic term, includes hydrocarbons, vegetable oils, shale oil, etc.

OLIGOTROPHIC WATER:  Water with a small or negligible supply of nutrients that therefore will support little organic production.

OPACITY:  The percentage of light transmission through a plume.

ORP:  Oxidation Reduction Potential.

ORTHOTOLIDINE:  A colormetric indicator for chlorine residual.  It is oxidized well in acid solution by chlorine and chloramines forming a yellow color.  It has been proposed as a method  of determining  divalent manganese which interferes with orthotolidine chlorine tests giving high readings.

OSMOSIS:  The  passage of  water through a permeable membrane separating two solutions of different concentrations; the water passes into the more concentration solution.

OTHER CHEMICALS:  Includes miscellaneous chemicals that may become involved in waste streams.  List of other chemicals:

         Detergents                                Polychlorinated Biphenyl

         Dissolved Gases                         Radioactive Materials

         Dissolved Oxygen                       Soaps

         Fat, Oil, Grease                          Used Oil

OXIDATION:   A chemical reaction in which an element or ion is increased in positive valence, losing electrons to an oxidizing agent.


PACKING:  The fill in a confined space in a stripping vessel, ranging from simply shaped units such as  rocks or slats to complex shapes that provide large surface area per unit volume.

PATHOGENS:  Disease causing microbes.

PCB:  Polychlorinated  Biphenyl  - used in transformer oils and some capacitors, carcinogen.

PERCENT DRY SOLIDS:  A waste treatment term specifying the percent dry solids in the filter cake or sludge.

PERIODIC  CHART:  An arrangement of the elements in order of increasing atomic number that  illustrates the repetition (or periodicity) of key characteristics.

PERMEABILITY:  The ability of a body to pass a fluid under pressure.

PESTICIDES/HERBICIDES:  The limitations on pesticides and herbicides reflect the requirements for potable water as well as the carcinogenic nature of many of these materials.  List of pesticides and herbicides:

Parathion              Demeton                  Malathion                    2-2-4-D

Aidrin                    Endosulfan              Methoxychlor               2-4-5-TP      

Chiordane              Endrin                     Mirex                           Malathion

Cushion                Heptachlor                Polyhedron                  Methoxychlor 

DDT                      Lindane                    Toxaphene

pH:  The measure of acidity or alkalinity of a solution.  It is the negative logarithm of the hydrogen ion concentration and as such represents the values on an exponential scale.  A pH of 7 is neutral, while a pH of 1 is strongly acidic and a pH of 14 is strongly basic.

PHOTOSYNTHESIS:  The process of converting carbon dioxide and water to carbohydrates activated by sunlight in the presence of chlorophyll, liberating oxygen.

PIN  POINT  FLOC:  Any floc that has not developed much beyond the macrofloc, or in the case of a poorly designed water plant, the remnant of a properly formed floc which has been mechanically sheared  or broken up to the original size of the macrofloc.

PLANKTON:  Unattached organisms of small, mostly microscopic size, that have little or no power of locomotion.

PLANKTON PHYTO:  Plant plankton

PLANKTON ZOO:  Protozoa and other animal plankton

POD:  Point of Discharge

POLLUTANT:  A contaminant at a concentration high enough to endanger the aquatic environment or the public health.

POLYMER:  A chain of organic molecules produced by the joining of primary units called monomers.

POTASSIUM  PERMANGANATE:  A powerful oxidizing agent which is gaining wide acceptance in  water treatment for the removal of taste and odor, soluble manganese, ferrous iron and color.  It is a dark purple crystalline substance, non-corrosive to iron and most plastic but readily attacks rubber.  CAUTION: Reacts violently with most organic materials.

PPB:  Parts per Billion.  Parts of material per billion parts of solution on a weight basis.

Parts  per  Million.  Parts of material per million parts of solution on a weight basis.

PRECIPITATE:  An insoluble reaction product;  in an aqueous chemical reaction, usually a crystalline compound that grows in size to become settleable.


RAG:  Debris that accumulates at an oil-water interface.

RBW:  Receiving Body of Water.  The lake, stream, canal. bay, etc. into which an effluent stream discharges.

REACTIVE WASTE:  Undergoes violent and rapid chemical reaction.

RECARBONATION:  Water that has been lime or soda ash softened is supersaturated with calcium  carbonate.  To prevent the eventual precipitation on filter sand, water mains, etc., carbon dioxide is  reacted with the calcium carbonate forming the soluble bicarbonate.  Where excess lime is used for magnesium removal, the carbon dioxide reduces the caustic alkalinity and soluble calcium.  Carbon  dioxide is generated by special coke ovens or natural gas burners.

REDOX  POTENTIAL:  Reduction-oxidation potential  measured against a standard electrode.

RED  WATER: A descriptive but nonspecific term for finely divided particulate matter contaminating finished water and imparting a brown or reddish cast.

REDUCTION:  A chemical reaction in which an element or compound gains electrons, being reduced in positive valence.

REVERSE OSMOSIS:  A process that reverses (by the application of  pressure) the flow of water in the natural process of osmosis so that it passes from the more concentrated to the more dilute solution.


SANITARY  SEWER:  Largely domestic wastewater plus some industrial waste.

SARA:  Superfund Amendments and Reauthorization Act.

SATURATION INDEX:  The relation of calcium carbonate to the pH, alkalinity and hardness of a water to  determine its scale-forming tendency.

SCALE:  The precipitate that forms on surfaces in contact with water as the result of a physical or chemical change.

SECONDARY CONTAINER:  Double wall tanks, buffer zone - EPA regulations.

SECONDARY TREATMENT:  This type of treatment refers to wastewater treatment for control of BOD, COD, suspended solids, turbidity, and bacteria and virus control.

SELECTIVITY:  The order of preference of an ion exchange material for each of the ions in the surrounding aqueous environment.

SEQUESTER:  To form a stable, water-soluble complex.

SHANNON WEAVER INDEX:  Measure of Shellfish Protection

SHORT  CIRCUIT:  Water current characteristics in a settling basin, lagoon, classifier and to a lesser degree in flocculators that channel a portion of the water or waste directly to the effluent or outlet without taking advantage of the detention time designed to give complete treatment.  It results in a poorly treated  or subquality effluent.  Some short circuiting is often seen in new  plants and can be easily alleviated by a number of methods.  

SILT DENSITY INDEX:  A measure of the tendency of a water to foul a reverse osmosis membrane, based on timed flow through a membrane filter at constant pressure.

 SIPS:  State Implementation Plans  -  state control on air pollution.

 SLIGHTLY HYGROSCOPIC:  (mildly  hygroscopic) terms often used to remind the reader that a product will take on moisture under some conditions although not nearly as deliquescent as a product such  as  calcium chloride or ferric chloride.  Testing under handling conditions is recommended since many variables affect the rate moisture can be absorbed.  Relative humidity, equipment surface  temperature and volume of air in the case of pneumatic systems are but a few.

 SLOP  OIL:  A general term in oil refining applying to tramp oil discharge to the oily sewer during shutdown and start-up or through abnormal operation.

 SLUDGE CONCENTRATION:  The percent of total solids in a sludge.

 SLUDGE VOLUME INDEX:  An inverse measure of sludge density.

 SLUDGE,  VOLUME  OF:  A waste treatment term specifying the cubic feet of sludge per million gallons of waste flow.

 SLUDGE, WEIGHT OF DRY SOLIDS:  A  waste  treatment  term specifying the pounds of dry sludge solids per million gallons of water flow.

 SLURRY:  A water containing a high concentration of suspended solids, usually over 5.000 mg/L.

 SOAPS:  Neutralization products of organic fatty acids, usually sodium based.

 SODA ASH:  A common water-treatment chemical, sodium carbonate.

 SOLIDS, SETTLEABLE:  Those solids that will settle without coagulation under quiescent conditions.    In waste treatment analysis an Imhoff Cone is generally used and settleable solids reported  as  mg/L.   This data will not correlate if coagulation is used due to the larger quantities of denser solids settled.

 SOLIDS, SUSPENDED:  True solids which will not settle under quiescent conditions within a reasonable  length of time.  Colloidal particles fall within this definition, but if solids determination is made by filtration, colloids will pass the filter and not be counted.  Since colloidal solids are one-fourth or more of  the total solids of domestic sewage, precise comment on the method of reporting results is important.  Suspended Solids content  -  in water treatment turbidity it is often a more convenient method of reporting than suspended solids.

 SOLIDS,  TOTAL,  T. S.:  A measure of all solids in a waste determined by evaporating it to dryness.

 SOLIDS, VOLATILE:  A measure of the amount of organic matter present in a waste determined by combustion under carefully controlled temperature conditions to covert organics to carbon dioxide and  water but not to volatilize inorganics which would result in a major error.

 SOLIDS,  WATER  TREATMENT:  True dissolved solids which greatly affect stability calculations, although often ignored.

 SOLID  WASTE:  Waste solids no longer usable to be disposed of or recycled

 SPCC:  Spill Prevention Control and Countermeasure

 STERILIZATION:  To free from living organisms.  Sometimes less correctly defined as the absence of lower organisms.

 STOKES'  LAW:  An expression for calculating the rate of fall of particles through a fluid based on densities, viscosity and particle size.

 STORM SEWER:  Collection system for surface run-off.

 SURFACE WATER:  Lakes, streams, canals, waterways, etc.

 SURFACTANT:  A surface active agent;  usually an organic compound whose molecules contain a hydrophilic group at one end and a lipophilic group at the other.


 TDS:  Total  Dissolved  Solids.  Represents the total material actually dissolved in the stream.  It is the same as salt dissolved in water and should not be confused with suspended solids or turbidity.  Total dissolved solids can include both organic and inorganic materials.

 TOC:  Total Organic Compounds

 TOXIC POLLUTANTS:  States must set specifications and cover in permits under NPDES by February 28, 1989.  Extensive fines.

 TP:  Total Phosphorus

 TSS:  Total Suspended Solids.  Represents the material held in suspension in the stream and subject to removal by settling or flotation.  They generally consist of insoluble organic material as well as sand, grit, and sometimes heavy metals.

 TURBIDITY:  A suspension of fine particles that obscures light rays but requires many days for sedimentation because of the small particle size.

 TURNOVER:  Sometimes called thermal turnover, fall or spring overturn.  It applies particularly to impoundments and lakes.  A naturally occurring physical mixing of the stratified zones often accompanied by great increase in manganese, iron, taste and odor.  It is usually caused by thermal changes resulting in disruptive density changes of water in one or more zones.  It is sometimes caused or augmented by wind.

 TYNDALL EFFECT:  The effect of light scattering or reflection by colloidal particles which does not occur with true solution.  If a particle is so small as not to exhibit this reflection of a strong  beam of light, it is usually considered molecular in size and not colloidal.  Some particles of organic color may open this definition to argument.


 UNIFORM HAZARD WASTE MANIFEST:  EPA form required for hazardous waste shipments.

 VENTURI:  A device for measuring fluid flow, including a short converging cane succeeded on the same axis by a long diverging cone.  This device is also used in gas scrubbing.


 WATER FLOODING:  A process of displacing oil from underground formations with water and returning it to the surface for recovery.


 ZETA  POTENTIAL:  The difference in voltage between the surface of the diffuse layer surrounding a colloidal particle and the bulk liquid beyond.


For details contact Pan Pacific Environmental Group or email us from our Literature Request Page

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Last modified: 02/10/09