水化學(xué)專(zhuān)業(yè)詞匯集萃

1、AAbsorption - The holding of a substance within a solid by cohesive or capillary forces.Accumulator - A pulsation dampener installed on the suction and/or discharge lines of pumps, generally plunger type, to minimize pressure surges and provide uniformity of flow.Accuracy - The closeness of agreemen

2、t between an observed value and an accepted reference value. Where an accepted reference value is not available, a measure of the degree of conformity of a value generated by a specific procedure to the assumed or accepted true value, and includes both precision and bias.Acetylation - Substitution o

3、f an acetyl radical for an active hydrogen. Specifically, formation of cellulose acetate from cellulose.Acidity - The quantitative capacity of aqueous media to react with hydroxyl ions.Activated Carbon - Granulated or powdered activated carbon used to remove tastes, odor, chlorine, chloramines, and

4、some organics from water. A family of carbonaceous substances manufactured by processes that develop adsorptive properties.Adsorption - The holding of a substance onto the surface of a solid by chemical surface forces, without forming new chemical bonds.Aerobic Bacteria - Bacteria that require oxyge

5、n for growth, see Bacteria, aerobes.Aggregate - Granular material such as sand, gravel, crushed stone.Air Scour - Distributing air over the entire filter area at the bottom of a filter media flowing upward to improve the effectiveness of backwashing and/or to permit the use of lower backwash water f

6、low rate.Algae - Any of a group of chiefly aquatic mono cellular plants with chlorophyll often masked by a brown or red pigment.Alkalinity - The quantitative capacity of aqueous media to react with hydrogen ions. "M" alkalinity is that which will react with acid as the pH of the sample is

7、reduced to the methyl orange endpoint about 4.5. "P" alkalinity is that which reacts with acid as the pH of the sample is reduced to the phenolphthalein end point of 8.3. "M" is the total alkalinity which is the sum of hydroxide plus carbonate plus bicarbonate contents; "P&q

8、uot; includes all the hydroxyl and half the carbonate content.Alum - Aluminum sulfate, Al2(SO4) 3XH2O (X=14-18), a coagulant.Ambient Temperature - The temperature of the surroundings, typically 20o-25oC.Amorphous - Non crystalline, devoid of regular cohesive structure.Anaerobic Bacteria - Bacteria t

9、hat do not use oxygen, oxygen is toxic to them, see Bacteria (anaerobes).Amphoteric - Capable of acting as an acid or a base.Angstrom (Å ) - A unit of length equaling 10-10 meters, 10-8 centimeters and 3.937 x 10-9 inches. The symbol is Å or A.U.Anion - An ion (electrically charged atom of

10、 group of atoms) that carries one or more negative charges, e.g., Cl-, OH-, SO4 =Anion Exchange Material - A material capable of the reversible exchange of negatively charged ions.Anisotropic Membrane - A nonuniform structure in cross-section; typically the support substructure has pores much larger

11、 than the barrier layer. (See Asymmetric Membranes).Anode - A positively (+) charged electrode that attracts anionsAnionic Polyelectrolyte - Usually acrylamide and acrylamide and acrylic copolymers, negatively charged, used for coagulation/flocculation, see Polyelectrolytes.Anthracite - A granular h

12、ard coal used as a filtration media, commonly used as the coarser layer in dual and multimedia filters.Antifoulant - See Antiscalant.Antiscalant - A compound added to a water which inhibits the precipitation of sparingly soluble inorganic salts.Anti-Telescoping Device - A plastic or metal device att

13、ached to the ends of a spiral wound cartridge to prevent movement of the cartridge leaves in the feed flow direction, due to high feed flows.AOC - Assimilable Organic Carbon.Applied Voltage - The DC voltage across the anode and cathode of each module. The voltage required depends primarily on the nu

14、mber of cells in the module.Aquifer - A water-bearing geological formation that provides a ground water reservoir.Aramid - A fully aromatic polyamide.Array - An arrangement of devices connected to common feed, product and reject headers i.e. a 2:1 array.Asymmetric Membrane - Membrane which has a cha

15、nge in pore structure with depth. (See Anisotropic Membranes).ATD - See Anti Telescoping Device.Atomic Weight - The relative mass of an atom based on a scale in which a specific carbon atom (carbon 12) is assigned a mass value of 12.ATP - Adenosine triphosphate.Autopsy - The dissection of a membrane

16、 module or element to investigate causes of unsatisfactory performance.Availability - The on-stream time or rated operating capacity of a water treatment system.A-Value - Membrane water permeability coefficient. The coefficient is defined as the amount of water produced per unit area of membrane whe

17、n net driving pressure (NDP) is unity, a unit of measurement is m3/hr/m2/kPa.AWWA - American Water Works Association.AWWARF - American Water Works Association Research Foundation.(Top) B Backwash - Reverse the flow of water w/wo air either across or through a medium or membrane designed to remove th

18、e collected foreign material from the bed or membranes.Bacteria - Any of a class of microscopic single-celled organisms reproducing by fission or by spores. Characterized by round, rod-like spiral or filamentous bodies, often aggregated into colonies or mobile by means of flagella. Widely dispersed

19、in soil, water, organic matter, and the bodies of plants and animals. Either autotrophic (self-sustaining, self-generative), saprophytic (derives nutrition from non-living organic material already present in the environment), or parasitic (deriving nutrition from another living organism). Often symb

20、iotic (advantageous) in man, but sometimes pathogenic. Bactericide - Agent capable of killing bacteria.Bacteriostat - Substance that prevents bacterial growth and metabolism but does not necessarily kill them.Bank - A grouping of devices. (See Array, Block, Train).Bar - A unit of pressure. One bar i

21、s equal to 14.5 psi, 1.02 kg/cm2, or one Pascal. By definition one bar is equal to one million dynes per square centimeter.BAT - Best Available Technology.Baume Scale - oBe - A measure of the density of a solution relative to water. Bed Depth - The depth of the filter medium or ion exchange resin in

22、 a vessel.Bed Expansion - The depth increase of filter medium or ion exchange resin that occurs during backwashing.Binders - In reference to cartridge filters, chemicals used to hold, or 'bind', short fibers together in a filter.Biocide - A substance that kills all living organisms.Biologica

23、l Deposits - The debris left by organisms as a result of their life processes.Biomass - Any material which is or was a living organism or excreted from a micro-organism.Biostat- A substance that inhibits biological growth. Blinding - In surface filtration, a build-up of particulates on the filter, r

24、estricting fluid flow through the filter at normal pressures.Block - A grouping of devices in a single unit having common control. (See array, Bank Train).BOD - Biochemical Oxygen Demand - The amount of dissolved oxygen utilized by natural agencies in water in stabilizing organic matter at specified

25、 test conditions.Body Feed - The continuous addition of filter medium (e.g.; diatomaceous earth) to sustain the efficacy of the filter.BOO - Build, Own Operate.BOOT - Build, Own, Operate and Transfer.Boundary Layer - A thin layer at the membrane surface where water velocities deviate significantly l

26、ess than those in the bulk flow.Brackish Water - Water with an approximate concentration of total dissolved solids ranging from 1000 to 10,000 mg/L. (See High Brackish Water and Sea Water).Breakpoint Chlorination - The point at which the water chlorine demand is satisfied and any further chlorine is

27、 the chlorine residual, the "free" chlorine species.Break Tank - A storage device used for hydraulic isolation and surge protection.Brine - The concentrate (reject) stream from a crossflow membrane device performing desalination. Portion of the feed stream which does not pass through the m

28、embrane.Brine (Concentrate) Seal - A rubber lip seal on the outside of a spiral wound cartridge which prevents feed by-pass between the cartridge and the inside pressure vessel wall.Brine Seal Carrier - See ATD.Brine System Staging - A process in which the concentrate, under pressure, of a group of

29、membrane devices is fed directly to another set of membrane devices to improve the efficiency of the water separation.Bubble Point Pressure - The pressure necessary to displace a liquid held by surface tension forces from the largest equivalent capillaries in a membrane filter.Bubble Point Test - A

30、non destructive membrane filter test used to assess filter integrity and proper installation.Bundle - A general term for a collection of parallel filaments or fibers.B-Value - Salt diffusion coefficient. The coefficient is defined as the amount of salt transferred per unit area of membrane when the

31、difference in salt concentration across the membrane is unity. A unit of measurement is m/hr.BWRO - Brackish Water Reverse Osmosis.(Top) C CAC - Combined Available Chlorine.Calcium Carbonate Equivalents (mg/L as CaCO3) - A method for expressing mg/L as ion in terms of calcium carbonate. Concentratio

32、n in calcium carbonate equivalents is calculated by multiplying concentration in mg/L of the ion by the equivalent weight of calcium carbonate (50) and dividing by the equivalent weight of the ion.Carbonate Hardness - The hardness in a water caused by carbonates and bicarbonates of calcium and magne

33、sium. The amount of hardness equivalent to the alkalinity formed and deposited when water is boiled. In boilers, carbonate hardness is readily removed by blowdown.Calcium Hypochlorite - Ca (HClO)2, a disinfection agent.Cartridge - See Spiral-Wound Cartridge.Catalyst - A substance whose presence init

34、iates or changes the rate of a chemical reaction, but does not itself enter into the reaction.Cathode - A negatively (-) charged electrode that attracts cations.Cation - An ion that carries one ore more positive charges, e.g., Na+ , NH4 + , Ca+2.Cation Exchange Material - A material capable of the r

35、eversible exchange of positively charged ions.Cationic Polyelectrolyte - A polymer containing positively charged groups used for coagulation/flocculation, usually dimethyl - aminoethyl methacrylate or dimethyl-aminoethyl acrylate. (See Polyelectrolyte.)CDI - Continuous Deionization. Commercial elect

36、rodeionization devices developed and sold by U.S. Filter.EDI - Continuous Electrodeionization. Electrodeionization where the ion transport properties of the active media are the primary sizing parametersCellulose - An amorphous carbohydrate (C6H10O5) that is the principal constituent of wood and pla

37、nts.Cellulose Acetate (CA) - In the broad sense, any of several esters of cellulose and acetic acid.Celsius (oC) - The designation of the degree on the International Practical Temperature Scale. Formerly called centigrade, oC = K minus 273.15 K= Kelvin.Centigrade - Since 1948, now called Celsius, a

38、temperature scale.Ceramic Membrane - Generally a glass, silica, alumina, or carbon based membrane. Generally used in micro and ultrafiltration. They tend to withstand high temperatures and wide pH ranges and be more chemically inert than polymeric membranes.CFU - Colony Forming Unit; unit used in th

39、e measure of Total Bacteria Count (TBC).Channeling - Unequal flow distribution in the desalination bundle or filter bed.Chelating Agents - A sequestering or complexing agent that, in aqueous solution, renders a metallic ion inactive through the formation of an inner ring structure with the ion.Chemi

40、cal Feed Pump - A pump used to meter chemicals, such as chlorine or polyphosphate, into a feed water supply.Chloramine - A combination of chlorine and ammonia in water which has bactericidal qualities for a longer time than does free chlorine.Chlorine - Chemical used for its qualities as a bleaching

41、 or oxidizing agent and disinfectant in water purification.Chlorine Demand - The amount of chlorine used up by reacting with oxidizable substances in water before chlorine residual can be measured.Chlorine Residual - The amount of available chlorine present in water at any specified time.Chlorine, F

42、ree Available - The chlorine (Cl2) hypochlorite ions (OCl-), hypochlorous acid (HOCl) or the combination thereof present in water.Chlorine, Total Available - The sum of Free Available Chlorine plus chloramines present in water.CIP - Cleaning-In-Place. Citric Acid - C3H4(OH)(COOH)3, membrane cleaning

43、 chemical.Clarifier - A tank in which precipitate settles and supernatant overflows, a liquid - solids separation unit using gravity to remove solids by sedimentation.Clark Degree - Number of grains of substance per one British imperial gallon of water expressed as CaCO3. Concentration in Clark or E

44、nglish degree is calculated by dividing concentration in calcium carbonate equivalents by 14.3. One grain weighs 1/7,000 pound and one imperial gallon of water weighs 10 pounds at 25oC. Coagulant - Chemical added in water and wastewater applications to cause destabilization of suspended particles an

45、d subsequent formation of flocs that adsorb, entrap, or otherwise bring together suspended matter that is so fine, it is defined as colloidal. Compounds of iron and aluminum are generally used to form flocs to allow removal of turbidity, bacteria, color, and other finely divided matter from water an

46、d waste water.Coalescing - The separation of mixtures of immiscible fluids (such as oil and water) based on different specific gravities and surface tensions. Can occur whenever two or more droplets collide and remain in contact and then become larger by passing through a coalescer. The enlarged dro

47、ps then separate out of solution more rapidly.COD - Chemical Oxygen Demand - The amount of oxygen required under specified test conditions for the oxidation of water borne organic and inorganic matter.Colloid - A substance of very fine particle size, typically between 0.1 and 0.001 microns in diamet

48、er suspended in liquid or dispersed in gas. A system of at least two phases, including a continuous liquid plus solid, liquid or gaseous particles so small that they remain in dispersion for a practicable time.Colony Forming Unit (CFU) - Unit used in the measure of Total Bacterial Count (TBC).Compac

49、tion - In crossflow filtration, the result of applied pressure and temperature compressing a polymeric membrane which may result in a decline in flux.Compartment - A unit in the Ionpure module which includes a dilute spacer and a concentrate spacer.Composite Membrane - A membrane having 2 or more la

50、yers with different physical or chemical properties. Membrane manufactured by forming a thin desalinating barrier layer on a porous carrier membrane. Concentrate - The stream exiting a crossflow membrane device which has increased concentration of solutes and particles over the feed stream. Portion

51、of the feed stream which does not pass through the membrane. The stream in which dissolved solids and/or particulates are concentrated in a membrane separation process.Concentrate Stream - The flow of water through the parallel concentrating compartments, where ions are collected.Concentrate Spacer

52、- Portion of the module compartment where salts are concentrated.Concentrate Recycle - A technique for improving recovery in which a fraction of the concentrate is recycled through the membrane system.Concentration Factor - CF = (Brine Concentration CB)/(Feedwater Concentration CF) - (1/(1 - Convers

53、ion)Concentration Polarization - The increase of the solute concentration over the bulk feed solution which occurs in a thin boundary layer at the feed side of the membrane surface, resulting from the removal of the solvent.Conductivity - The electrical measurement of water's ability to conduct

54、an electrical current, which is dependent on the concentration of ions in the water and its temperature. Units are microsiemens/cm or mS/cm or micromhos/cm and are normalized to 25 deg C.Contaminant - Any foreign substance present which will adversely affect performance or quality.Continuous Deioniz

55、ation - A deionization process that does not require regular interruptions in service to discharge ionic materials collected from the water being processed.Control Block - A group of devices having a common piping and control system.Conversion (Y) - Product water flow rate divided by feed water flow

56、 rate. Also called recovery; given as fraction or decimal. (See Recovery). Corrosion Products - Products that result from chemical or electrochemical reaction between a metal and its environment.CPU - Chloroplatinate Unit (color indicator).Crossflow Membrane Filtration - A separation of the componen

57、ts of a fluid by semipermeable membranes through the application of pressure and flow parallel to the membrane surface. Includes the processes of reverse osmosis, ultrafiltration, nanofiltration, and microfiltration.Current Draw - The DC current through each module. The current depends on the ion lo

58、ad in the feed, on the module recovery rate, and on the amount of water splitting. Roughly independent of the number of cells.Current Efficiency - Theoretical current required to transport the feed ions divided by the actual current. Expressed as %.(Top) D Dalton - An arbitrary unit of molecular weight, 1/12 the mass of the nuclide of carbon 12. Unit of measure for the smallest size of the molecule retained by