Water Hygiene Glossary

Water Hygiene Glossary

By on Mar 14, 2017 in Blog |

Looking to de-boggle some of our water hygiene jargon?! We’ve put together a handy glossary so you can figure out your TMV’s from your TVC’s!

 

  • Aerosol – A suspension of particles, dispersed in a gas.
  • Algae – a simple, non-flowering, and typically aquatic plant of a large assemblage sometimes found in water tanks.
  • Antibodies – a blood protein produced in response to and counteracting a specific antigen. Antibodies combine chemically with substances which the body recognises as alien, such as bacteria, viruses, and foreign substances in the blood.
  • Anti-corrosive chemicals – Anti-corrosive chemicals protect metals by either passivating the metal (by the promotion of a thin metal oxide film i.e. anodic inhibitors), or by physically forming a thin barrier film by controlled deposition (cathodic inhibitors).
  • Artificial water systems – Any water system that has been constructed and does not occur naturally such as a hot water system.
  • Audits – An official examination and inspection to verify the efficacy of a system. In the case of a Legionella audit, this includes an evaluation of the existing risk management system, assessment reports and other protocols to ensure compliance with the law.
  • Bacteria – The singular of bacterium, a microscopic, unicellular (or more rarely multicellular) organism.
  • Biocides – A biocide can be defined as either a chemical substance or microorganism that can be used to prevent, make harmless or control another harmful organism by either chemical or biological interaction.
  • Biodispersants – A chemical product that can be added to recirculating water within a cooling system to penetrate and break down biofilms.
  • Biofilm – A biofilm is defined as a coating of microorganisms where the cells stick to each other and onto a surface. Biofilm is commonly described as slime forming bacteria and often include species such as Pseudomonas.
  • Blow down / Bleed off – Water discharged from a plumbing system to control the concentration of salts or other impurities in the circulating water; usually expressed as a percentage of recirculating water flow.
  • Calorifier – A piece of equipment that is utilised to transfer heat to water in a contained unit by indirect heat transfer of heat contained in a coil or pipe work which is then immersed into the cold water supply. Any such water containing vessel can therefore be defined as a calorifier.
  • CFU  (Colony Forming Units) – A unit of measurement used in microbiology that indicates the number of microorganisms present in a water sample. It is normally measured by the number of colony forming units (CFU) present in one millilitre of water.
  • Chlorine – A chemical element commonly used for water purification, chlorine is an oxidising biocide.
  • Cold Water Services (CWS) – Installation of plant, pipes and fittings in which cold water is stored, distributed and subsequently discharged.
  • Concentration Factor – This is the result of a comparison calculation made between the levels of total dissolved solids in a cooling tower circuit against the total dissolved solids in a cooling towers make up water supply for example. A term cycles of concentration is often used in the industry and reflects a comparison between indicator constituents of two bodies of water.
  • Cooling Tower – A cooling tower is a heat rejection device which rejects waste heat to the atmosphere through the cooling of a water stream to a lower temperature. Cooling towers vary in size from small roof-top units to very large hyperboloid structures often associated with power plants. The vast majority of cooling towers are much smaller, including many units installed on or near buildings to discharge heat from air conditioners.
  • Corrosion – Corrosion is defined as the gradual destruction or degradation of a material. Metals are prone to corrosion by chemical reaction with oxygen in the environment.
  • Corrosion Inhibitors – A corrosion inhibitor comprises a chemical substance that if introduced to a liquid or gas contain in a vessel will reduce the level or rate of degradation to the vessel in which the liquid or gas is stored.
  • Dead End / Blind End – A dead end or blind end is a pipe which is closed at one end and therefore no water passes through.
  • Dead Legs – A deadleg describes a pipe leading to a fitting through which water only passes when there is draw-off from the fitting.
  • Decontamination – The process of removing or neutralising pathogenic bacteria in a water or other system.
  • Dip Slide – A dip slide is a piece of equipment used to analyse the microbial content of dirty water. It includes a sterile case and dip stick with a culture media or agar which is used by immersing the stick into the body of water and then replacing it in its sterile container. The whole unit is then placed in an incubator to facilitate bacterial growth. The resulting growths are then read against a chart to provide an indication of water quality.
  • Disinfection – A process which destroys or irreversibly inactivates micro-organisms and reduces their number to a non-hazardous level.
  • Distribution Circuit – The system of pipes and equipment used to move water from one point to another where water can then be used at one more appliance, system or fitting within a building.
  • Domestic Water Services – Hot and cold water intended for personal hygiene, culinary, drinking water or other domestic purposes.
  • Drift – Drift in the water industry is defined by the calculation of water lost from a system or cooling tower in liquid droplet form that has become suspended in the system exhaust and is then released into the atmosphere. Drift eliminators are fitted to reduce such water loss for example.
  • Drift Eliminator – Drift eliminators comprise a piece of equipment which is designed to prevent water droplets passing through it. Whilst most do not completely stop all water droplets from passing they come various different designs that have varied levels of efficiency in the task they are designed to achieve.
  • Evaporative Condensor – A heat exchanger in which a refrigerant is cooled by a combination of air movement and water spray.
  • Evaporative Cooling – The reduction in temperature resulting from the evaporation of a liquid, which removes latent heat from the surface from which evaporation takes place. This process is used in industrial and domestic cooling systems.
  • Flushing – The process of draining and cleaning a cooling system, including all associated pipework.
  • Fouling – Organic growth or other deposits on heat transfer surfaces causing loss in efficiency.
  • Half-life – The ratio of system volume to purge rate.
  • Hot Water Services (HWS) – Installation of plant, pipes and fittings in which water is heated, distributed and subsequently discharged (not including cold water feed tank or cistern).
  • Legionella – The bacterium (Legionella pneumophila) which causes Legionnaires’ disease, flourishing in air conditioning and central heating systems.
  • Legionella Audits – Independent verification and validation of the control measure put in place to manage the risk of Legionella. The audit will normally cover aspects of the system, records, management, training, etc to ensure all compliance and safety risks are being suitably managed.
  • Legionellae – The group name of Legionella bacteria. There are in excess of 50 difference species of which some are known to be fatal to humans. Legionallae bacteria are prevalent in both natural and built environment aquatic systems.
  • Legionella Sampling – The collection and laboratory testing of samples from a water system in order to monitor the presence of bacteria, both general (aerobic) bacterial species and Legionella bacteria.
  • Legionellosis – Any illness caused by exposure to legionella.
  • Legionnaires’ Disease – A potentially fatal bacterial pneumonia infection caused by Legionella bacteria.
  • Make-Up Water – Make up water is the water added to a cooling tower or equipment to replace water that has been lost of wasted due to leaks, evaporation, bleed off or discharge.
  • Micro-organism – Any organism too small to be viewed by the unaided eye, including bacteria, protozoa and some fungi and algae.
  • Non-oxidising biocide – Non-oxidising biocides comprise chemicals or microorganisms that become effective by means of disrupting or interfering with the target organisms structure or metabolisms which then renders the target organism harmless or effective.
  • Nutrients – A food source for micro-organisms.
  • Oxidising biocides – Special chemical agents capable of oxidising organic matter e.g. cell material, enzymes or proteins associated with microbiological populations, resulting in death of the micro-organism.
  • Parts Per Million (PPM) – A measure of dissolved substances given as the number of parts there are in a million parts of solvent. It is numerically equivalent to milligrams per litre mg/l with respect to water.
  • Pasteurisation – Heat treatment to destroy micro-organisms.
  • Plank Tonic – A micro-organism that is free floating in a body of water or aquatic environment.
  • Plume – The visible discharge of air and moisture from a cooling tower or other scooling system.
  • Pond / Sump – Collection of cooling water at the base of a cooling tower.
  • Pontiac Fever – Pontiac fever is a disease caused by species of legionella, an upper respiratory illness less severe than Legionnaires’ disease.
  • PPE (Personal Protective Equipment) – Personal protective equipment is used to protect personnel during hazardous operations.
  • Retention Time – The length of time a chemical remains in the system or length of time a chemical needs to be maintained in a system to clean it sufficiently.
  • Risk Assessment – Identifying and assessing the risk from Legionella from work activities and water sources on premises and determining any necessary precautionary measures.
  • Scale – Crystalline deposits that form on plumbing system surfaces or pipework. Scale normally results from a build-up of unwanted minerals, commonly calcium carbonate.
  • Scale Inhibitors – Chemicals or substances used to control scale formation and build up on surfaces or within a system. Scale inhibitors can work by either disruption the precipitation process and or preventing the formation of scale crystals to prevent build up.
  • Schematic Drawing – A schematic, or schematic drawing, is a representation of the elements of a system using abstract, graphic symbols rather than realistic pictures.
  • Sentinel Taps – The Sentinel taps are defined as the first and last taps on a water distribution system. For hot systems the nearest and further form the water heater or calorifier. For cold water systems the sentinel will be the nearest and furthest taps from the cold water storage tanks.
  • Serogroup – A sub-group of the main species.
  • Sessile – Aquatic micro-organisms adhering to a surface normally as part of a biofilm.
  • Shunt Pump – A circulation pump fitted to hot water service/plant to overcome the temperature stratification of the stored water.
  • Slime – A mucus-like exudate which covers a surface produced by some micro-organisms.
  • Sludge – A general term for soft mud-like deposits found on heat transfer surfaces or other important sections of a cooling system. Also found at the base of calorifiers and cold water storage tanks.
  • Spa Pools – Also known as a hot tub or Jacuzzi, a spa pool is a self-contained body of warm water designed for sitting in (not whole body immersion). The water is re-circulated and kept between 30 – 40°C and is usually not drained between use, being continually filtered and cleaned. A hydro-jet circulation, with or without an air induction bubble system, is also used to agitate the water.
  • Stagnation – Stagnation occurs when water is prevented from flowing in any direction. Such conditions encourage bacterial growth and particularly the growth of Legionella.
  • Strainers – Strainers or course filters are used to remove or separate any debris or constituents in a body of water to reduce the risk of such debris effecting the efficient operation of a system. Various grades and types of strainers and filters existing and are used. The type used often depends on the required quality of water required to maintain efficiency or prevent damage to sensitive components or pumps for example.
  • Thermal Disinfection – When heat is used to kill bacteria or micro-organisms living on a surface or in solution.
  • Thermostatic Mixing Valve (TMV) – A blending valve or device where cold water is mixed into the hot water supply to deliver a tap outlet with warm water set to a predefined temperature.
  • Total Viable Count (TVC) – TVC gives a quantitative idea about the presence of microorganisms such as bacteria, yeast and mould in a sample. To be specific, the count actually represents the number of colony forming units (cfu) per g (or per ml) of the sample.
  • Water Heater – A water heater, also referred to as a calorifier, is used for the transfer of heat to water in a vessel, the source of heat being contained in a pipe or coil immersed in the water.
  • Windage – Physical loss of water from a cooling tower caused by draught of air or wind – water is lost around the base of the cooling tower as a result of cross winds as opposed to drift.