Challenge testing: tests conducted to determine the efficiency of removal of target particulates such as a microbes or surrogates in order to calculate the Log Reduction Value of a treatment process.
chlorination: Use of chlorine as a means of disinfection.
coliform bacteria: Group of bacteria whose presence in drinking water can be used as an indicator for operational monitoring.
contaminant: Biological or chemical substance or entity, not normally present in a system, capable of producing an adverse effect in a biological system, seriously injuring structure or function.
critical control point: A point, step or procedure at which control can be applied and that is essential for preventing or eliminating a hazard, or reducing it to an acceptable level.
critical limit: A prescribed tolerance that must be met to ensure that a critical control point effectively controls a potential health hazard; a criterion that separates acceptability from unacceptability.
Cryptosporidium: Microorganism commonly found in lakes and rivers that is highly resistant to disinfection. Cryptosporidium has caused several large outbreaks of gastrointestinal illness, with symptoms that include diarrhoea, nausea and stomach cramps.
disinfectant: An oxidising agent (eg chlorine, chlorine dioxide, chloramines and ozone) that is added to water in any part of the treatment or distribution process and is intended to kill or inactivate pathogenic (disease-causing) microorganisms.
disinfection: The process designed to kill most microorganisms in water, including essentially all pathogenic (disease-causing) bacteria. There are several ways to disinfect, with chlorine being most frequently used in water treatment.
disinfection byproduct: Products of reactions between disinfectants, particularly chlorine, and naturally occurring organic material.
drinking water: Water intended primarily for human consumption ( excluding bottled water).
drinking water quality monitoring: The wide-ranging assessment of the quality of water in the distribution system and as supplied to the consumer, which includes the regular sampling and testing performed for assessing conformance with guideline values and compliance with regulatory requirements and agreed levels of service.
effluent: The out-flow water or wastewater from any water processing system or device.
Escherichia coli: Bacterium found in the gut, used as an indicator of faecal contamination of water.
exposure: Contact of a chemical, physical or biological agent with the outer boundary of an organism (eg through inhalation, ingestion or dermal contact).
Giardia lamblia: A protozoan frequently found in rivers and lakes. If water containing infectious cysts of Giardia is ingested, the protozoan can cause a gastrointestinal disease called giardiasis.
hazard: A biological, chemical, physical or radiological agent that has the potential to cause harm.
hazard analysis critical control point (HACCP) system: A systematic methodology to control safety hazards in a process by applying a two-part technique: first, an analysis that identifies hazards and their severity and likelihood of occurrence; and second, identification of critical control points and their monitoring criteria to establish controls that will reduce, prevent, or eliminate the identified hazards.
hazard control: The application or implementation of preventive measures that can be used to control identified hazards.
hazardous event: An incident or situation that can lead to the presence of a hazard (what can happen and how).
helminth: A worm-like invertebrate of the order Helminthes. A parasite of humans and other animals.
indicator: Measurement parameter or combination of parameters that can be used to assess the quality of water; a specific contaminant, group of contaminants or constituent that signals the presence of something else (eg Escherichia coli indicate the presence of pathogenic bacteria).
indicator organisms: Microorganisms whose presence is indicative of pollution or of more harmful microorganisms.
Log reduction value (LRV): A measure of the ability of a treatment process to remove, kill, or inactivate pathogens such as bacteria, protozoa and viruses. Calculated by taking the logarithm of the ratio of pathogen concentration in the influent and effluent water of a treatment process. (1-log removal = 90% reduction in density of the target organism, 2-log removal = 99% reduction, 3-log removal = 99.9% reduction, etc).
microorganism: Organism too small to be visible to the naked eye. Bacteria, viruses, protozoa, and some fungi and algae are microorganisms.
monitoring: Systematically keeping track of something, including sampling or collecting information and documenting it.
multiple barriers: Use of more than one preventive measure as a barrier against hazards.
operational monitoring: The planned sequence of measurements and observations used to assess and confirm that individual barriers and preventive strategies for controlling hazards are functioning properly and effectively.
pathogen: A disease-causing organism (eg bacteria, viruses and protozoa).
Pathogen surrogate: An organism, particle, or substance used to study the fate of a pathogen in a specific environment.
pH: An expression of the intensity of the basic or acid condition of a liquid. Natural waters usually have a pH between 6.5 and 8.5.
potable (drinking) water: Water suitable on the basis of both health and aesthetic considerations for drinking or culinary purposes.
Protocol: A system of rules that explains the correct conduct and procedures to be followed.
protozoa: A phylum of single-celled animals.
recycled water: Water generated from sewage, greywater or stormwater systems and treated to a standard that is appropriate for its intended use.
residual risk: The risk remaining after consideration of existing preventive measures.
risk: The likelihood of a hazard causing harm in exposed populations in a specified time frame, including the magnitude of that harm.
risk management: The systematic evaluation of the water supply system, the identification of hazards and hazardous events, the assessment of risks, and the development and implementation of preventive strategies to manage the risks.
secondary effluent: The liquid portion of wastewater leaving secondary treatment.
source water: Water in its natural state, before any treatment to make it suitable for drinking.
target criteria: Quantitative or qualitative parameters established for preventive measures to indicate performance; performance goals.
tertiary treatment: Includes treatment processes beyond secondary or biological processes, which further improve effluent quality. Tertiary treatment processes include detention in lagoons, conventional filtration via sand, dual media or membrane filters, which may include coagulant dosing and land-based or wetland processes.
toxicity: The extent to which a compound is capable of causing injury or death, especially by chemical means.
Validation: The substantiation by scientific evidence (investigative and/or experimental studies) of a treatment process and operational criteria, to ensure capability to effectively control hazards.
virus: Molecules of nucleic acid (RNA or DNA) that can enter cells and replicate in them.
water recycling: A generic term for water reclamation and reuse. It can also be used to describe a specific type of ‘reuse’ where water is recycled and used again for the same purpose (eg recirculating systems for washing and cooling), with or without treatment in between.