Introduction to Desalination. Louis Theodore

that forms a monovalent anion; is the form of nitrogen that is produced from the aerobic oxidation of ammonia (nitrification); and that serves as an electron acceptor for the anaerobic oxidation of organic matter (denitrification); it is a nutrient that can result in eutrophication of lakes and ponds and is the cause of “blue baby” syndrome in humans if in high concentrations in drinking water: its MCL is 10 mg/L in drinking water.

       Nonpoint source – A source of pollutant discharge that is not traceable to a discrete location.

       Non-potable water – Water considered unsafe and/or unpalatable for drinking (see also potable water).

       Nutrient – Any element or compound that is essential to the life and growth of plants or animals, either as such or as transformed by chemical or enzymatic reactions; nitrogen and phosphorous are the major nutrients of concern in polluted waters.

       Ocean water (seawater) – A uniform solution contained approximately 96.5% water and 3.5% ionized salts; ingestion of substantial amounts will create a bodily chloride imbalance with harmful effects.

       Oceanic – A term used to describe the parts of the oceans deeper than 200 meters.

       Oceanography – The science dealing with oceans, including their form, physical and chemical features, and related phenomena.

       Open channel – Any natural or artificial waterway or conduit in which a fluid flows with a free surface exposed to atmospheric pressure.

       Osmosis – The passage of a pure liquid (usually water) through a semipermeable membrane from a solution of low concentration into a solution of a higher concentration (e.g. the flow of pure water into a solution of salt and water); see also reverse osmosis.

       Osmotic pressure – The pressure that results from osmosis.

       Outfall – The place where an effluent is discharged into a receiving water.

       Outfall sewer – A pipe or conduit that transports wastewater effluent to a final point of discharge.

       Oxygenation – The increase of the dissolved oxygen content within water through aeration.

       Ozonation – The addition of ozone to a water supply to reduce taste and odor problems and for disinfection.

       Ozonator – A device that creates ozone from oxygen and adds it to water.

       Parts per billion (ppb) – The fraction (ppbm for mass fraction and ppbv for volume fraction) multiplied by 109; it is a unit used to measure extremely small concentrations of a substance; equivalent to units of µg/L in water.

       Parts per million (ppm) –The fraction (ppmm for mass fraction and ppmv for volume fraction) multiplied by 106; it is a unit used to measure small concentrations of a substance; equivalent to units of mg/L in water.

       Pathogenic waste – A discarded waste that contains organisms capable of causing disease.

       Percolation – The flow of a liquid downward through a filtering medium or soil layer.

       Permafrost – The portion of the Earth which is permanently frozen, such as the Artic regions and portions of Alaska.

       Permeability – The degree to which a liquid can move freely through soils.

       Physical quality – The physical characteristics possessed by a material; it includes temperature, color, odor, and turbidity.

       Physical treatment – A water or wastewater treatment process that utilizes physical means for pollutant removal; processes include screening, grinding, settling, filtration, and centrifugation.

       Physicochemical – A term used to describe processes that involve both physical and chemical characteristics; adsorption is one such process that involves both physical and chemical attraction of an adsorbate to an adsorption site.

       Point source of pollution – Pollution originating from a discrete source, such as the outflow from a pipe, ditch, tunnel, concentrated animal-feeding operation, or floating craft.

       Pollutant – Any harmful substance present in air, water, or soil.

       Pollution – The direct or indirect alteration of the physical, thermal, biological, or radioactive properties of any part of the environment in such a way as to create a hazard or potential hazard to the health, safety, or welfare of any living species.

       Potable water – Water that is safe for human consumption.

       POTW – Publicly owned treatment works, or municipal wastewater treatment plants.

       Pre-aeration – A water treatment process in which the removal of dissolved gases, and the addition of oxygen are performed; typically, in aeration towers or aeration tanks.

       Precipitate – A solid that separates out from a liquid due to some physical or chemical change in the liquid.

       Pretreatment – Any process employed to partially remove pollutants from water prior to any subsequent treatment process.

       Psychrometric chart – A chart employed to determine the properties of moist air as a function of temperature.

       Public water system (PWS) – Any system that provides piped water for human consumption to at least 15 service connections or regularly serves 25 individuals.

       Purging – A cleansing or removal of impurities, foreign matter, or undesirable contaminants from a process through periodic withdrawals of liquids or solids.

       Purification – The removal of undesirable constituents from a substance by one or more separation techniques.

       Rank – The stage reached by coal in the course of its carbonation; the chief ranks, in order of increasing carbon content, are lignite, subbituminous coal, bituminous coal, and anthracite.

       Raw water – The untreated water that enters the first treatment unit of a water treatment plant.

       Receiving water – Any body of water (e.g. river, lake, ocean, stream, etc.) into which treated wastewater is discharged to.

       Recirculating cooling water – The recycling of cooling water to greatly reduce water use by reusing the water to perform several cooling operations.

       Reclaimed water – Treated wastewater that is reused for generally non-potable uses to supplement or replace other raw water supplies.

       Recycled water – Wastewater that has been treated for reuse and is recycled, generally for non-potable uses within a home or industrial facility.

       Red tide – A proliferation and accumulation of certain microscopic algae, predominantly dinoflagellates, in coastal waters; some species produce toxins that are labeled harmful algae blooms, or Harmful Algal Blooms (HABs), that pose a serious and recurring threat to human health, wildlife, marine ecosystems, fisheries, and coastal aesthetics.

       Red water – A rust-colored water, usually resulting from the presence of precipitated ferric iron salts.

       Release – Any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment.

       Renewable water supply – The rate of supply of water (volume per unit time) potentially or theoretically available for use in a region on an essentially permanent basis.

       Reproducibility – The ability to repeat an experiment, reaction, measurement, or process and produce the same results.

       Reservoir – Any body of water employed for the storage, control, or regulation of water.

       Reverse osmosis – A water treatment process employed to separate water from pollutants by the application of pressure to force the water through a semipermeable membrane.

       Rinse – The removal