FilmTec Technical Manual - Chester Paul Company

PolarizationSee concentration polarization.PolyelectrolyteSynthetic (or natural) molecules, containing multiple ionic groups, used as coagulants andflocculants; available as anionic, cationic and nonionic.PolymersA substance consisting of molecules characterized by the repetition of one or more types ofmonomeric units.PorosityThat portion of a membrane filter volume which is open to fluid flow, also known as void volume.Post treatmentThe addition of chemicals to the product or concentrate stream to make it suitable for thedesired end use application.Post treatmentUtilization of equipment such as degasifiers to make the product or concentrate stream, orboth, suitable for the desired end use application.Pressure filtrationFiltration performed in an enclosed pressurized filter vessel.Pressure vesselThe vessel containing one or more individual membrane elements and designed to withstandsafely the hydraulic pressure driving the separation mechanism.PretreatmentProcesses such as chlorination, filtration, coagulation, clarification, acidification which may beused on feedwater ahead at membrane devices to improve quality, minimize scaling andcorrosion potential, control biological activity.Product channel spacer The fabric or other material through which permeate water flows after it passes through the(permeate carrier)flat sheet membrane.Product stagingA process in which the permeate from one membrane plant is used as the feed to anothermembrane plant in order to further improve product quality.Product tubeThe tube at the center of the spiral wound cartridge which collects permeate waterProductivityFlow rate of product water.Product waterPurified water produced by a process. See Permeate.ProjectionA calculation usually performed by a software package, which predicts the performance ofparts or all of a water plant.PyrogensAny substance capable of producing a fever in mammals. Often a bacterial endotoxin such aslipo polysaccaride generated by gram negative bacteria at destruction. Chemically andphysically stable, pyrogens are not necessarily destroyed by conditions that kill bacteria.Raw waterWater which has not been treated. Untreated water from wells, surface sources, the sea orpublic water supplies.Recovery – Y (conversion) The ratio of product quantity (permeate stream flow rate) over the feed quantity (feed streamflow rate), given as fraction or in percent.RejectBrine, (concentrate) stream from a desalination device. Portion of the feed stream which doesnot pass through the membrane.Rejection The ability of the membrane to hinder certain elements from passing through. Expressed as 1minus the ratio between the concentration in the product and the feed.RetentateSee concentrate.Reverse Osmosis (RO) The separation process where one component of a solution is removed from anothercomponent by flowing the feed stream under pressure across a semipermeable membrane.RO removes ions based on electro chemical forces, colloids, and organics down to 150molecular weight. May also be called hyperfiltration.ROReverse Osmosis.RO trainOne of two or more complete RO installations, including membranes and high pressure pumpoperating in parallel.S&DSIStiff & Davis Stability Index.SalinityThe concentration of inorganic salts in water.Salt fluxAmount of dissolved salt passing through the membrane, moles per day per square unit ofCPx100membrane area. salt passage, SP- SP =CFSanitizationReduction in the number of bacterial contaminants to safe levels. See disinfection.SaturationThe point at which a solution contains enough of a dissolved solid, liquid, or gas so that nomore will dissolve into the solution at a given temperature and pressure.Page 160 of 180 ® Trademark of The Dow Chemical Company ("Dow") or an affiliated company of Dow Form No. 609-00071