Glossary

Acid

A chemical substance with a pH of less than 7, which can corrode, react with or dissolve other materials.

Aeration

A process where air is mixed through or dissolved in a liquid or substance.

Aerobic

Requiring oxygen.

Algae

Unique plant-like organisms that capture energy from the sun to make food.

Algal bloom

A large and sudden growth of algae  that can be harmful to waterways.

Alkaline

A substance with a pH value of greater than 7.

Alum

A chemical used in water treatment called a coagulant. It causes small particles to stick together so they can be more easily removed.

Amenities

Things that provide comfort or convenience such as  toilets, taps and bathrooms.

Anaerobic

Able to live without oxygen.

Anoxic

Something that contains no free oxygen.

Atmospheric hazard

Hazard event originating in the atmosphere, like storms or tropical cyclones.

Atom

A basic unit of matter consisting of a central nucleus surrounded by negatively charged electrons.

Aquatic

Living or growing in water.

Atmosphere

Gases that surround a planet, like the air that surrounds earth.

Biodegradable

A substance that can be broken down into harmless products in the environment.

Biodiversity

The variety of all living things.

Biological

Refers to living matter.

Biological Oxygen Demand (BOD)

A measure of the amount of oxygen used by microorganisms in water when breaking down nutrients such as nitrogen and phosphorus.

Biological processes

The processes of a living organism, like turning food into energy.

Biological reactor

A wastewater treatment system that uses microorganisms to treat effluent.

Biological treatment

Using bacteria and other simple organisms to break down nutrients and organic materials in wastewater.

Biome

A major terrestrial vegetation community, like a tropical forest, a temperate grassland or a desert.

Biosolids

A solid substance formed from the by-products of wastewater treatment.  These solids can be beneficially used by agriculture or forestry.

Biosphere

The area of the earth where living things are found.

Blackwater

Wastewater containing faecal matter and other pathogens.Biodegradable
A substance that can be broken down into harmless products in the environment.

Biodiversity

The variety of all living things.

Biological

Refers to living matter.

Biological Oxygen Demand (BOD)

A measure of the amount of oxygen used by microorganisms in water when breaking down nutrients such as nitrogen and phosphorus.

Biological processes

The processes of a living organism, like turning food into energy.

Biological reactor

A wastewater treatment system that uses microorganisms to treat effluent.

Biological treatment

Using bacteria and other simple organisms to break down nutrients and organic materials in wastewater.

Biosolids

A solid substance formed from the by-products of wastewater treatment.  These solids can be beneficially used by agriculture or forestry.

Biosphere

The area of the earth where living things are found.

Blackwater

Wastewater containing faecal matter and other pathogens.

Catchment

An area of land that collects rainwater as it falls to earth and flows to a common point. Often used to refer to the area of land and waterways that feeds into dams.

Chemical

A substance made up of specific elements.

Chlorine

A gaseous chemical element.

Clarification

To remove solid particles from a liquid or solution.

Climate

Long term weather patterns.

Climate change

Changes in climate over a long time due to natural and/or human causes.

Cloudy water

Water that is not clear.

Coagulant

Chemicals that attract and bind together small particles called floc so they can be more easily removed.

Coagulation

A process causing small particles to bind together and form larger ones (‘floc’). This makes them bigger, heavier and easier to remove.

Community

A group of plants, animals or people living together in the one place.

Compost

A mixture of decomposed plant materials, such as vegetable peelings, leaves and animal waste.

Concentration

The amount of one substance dissolved in another.

Condensation

The changing of a gas into a liquid such as water vapour turning into a liquid.

Conservation

Protection of resources so they are not degraded, depleted or wasted.

Contamination

Polluting something by adding a substance or contaminant to it.

Corrosion

Deterioration in metals caused by oxidation or chemical reaction from water, air or acid.

Cryptosporidium

A simple one-celled microorganism or parasite that lives in the intestines of vertebrates, including humans.

Dam

A wall or barrier built across a river to hold water.

Deepwater ocean outfall

An underwater tunnel or pipe that carries treated wastewater into deep ocean water where it is diluted and dispersed.

Degradation

The wearing down of the land by the erosive action of water, wind or ice. In chemistry: the breakdown of an organic compound.

Dehydration

The process of removing water from something.

Desalination

The process of removing salt from ocean water to make drinking water.

Detergents

A substance used for cleaning. Usually a powder or liquid that is mixed with water to remove dirt.

Disinfection

A chemical process that kills microorganisms capable of causing infectious disease.

Discharge

To release water into a river or the ocean.

Dissolve

If one substance is soluble in another, then it will dissolve in that substance.

Dissolved oxygen

Oxygen that is dissolved in water.

Dissolved salts

Inorganic substances (eg sodium chloride) that are dissolved in water.

Distilled water

Water that has had almost all of its impurities removed.

Drinking water

Water intended for human consumption but which also has other uses.

Ecosystem

A community of organisms, interacting with one another, within the environment in which they live.

Effluent

What wastewater becomes after it has been treated at a wastewater treatment plant. 

Effluent reuse

A process where treated wastewater is recycled for beneficial purposes.

Environment

The physical, chemical and biotic surroundings of something.

Environmental flow

Water released from dams and reservoirs to maintain the environmental flow of rivers, and the plants and animals that rely on this water. 

Erosion

The wearing away of the earth’s surface by wind and water.

Estuarine

Relating to or found in estuaries.

Estuary

The lower part of a river system where fresh water from coastal catchments mixes with ocean waters.

Eutrophication

A form of water pollution caused by an excess of nutrients in the water. Usually leads to excessive growth of algae.  

Evaporate

To convert a liquid into a gas, such as liquid water into water vapour.

Evaporation

The process of converting a liquid into a gas, such as liquid water into water vapour.

Faecal coliform bacteria

A bacteria found in the intestines of a mammal. Used to test for faeces in waterways.

Fair test

A test where one variable is changed at a time and all the other conditions are kept the same.

Ferric chloride

An iron-based chemical used in water and wastewater treatment. Also known as iron (III) chloride.

Fertiliser

Natural or chemical materials used to make soil more productive.

Field work

An investigation done in the normal environment of the subject of the study, rather than in a laboratory or office.

Filters

Devices that remove solid impurities from a liquid or solution passing through them.

Filtration

A process to remove solid particles from a liquid or solution by passing it through a filter.

First-hand investigation

An investigation based on direct personal observation or experience.

Floc 

The larger particles formed when smaller particles stick together with the aid of a coagulant during the process of flocculation.

Flow

The movement of water in a waterway due to gravity.

Flow rate

The amount of water that flows from a water device in a given time.

Fluoride

A type of chemical, often used in water supply to reduce tooth decay.

Geographical processes

The physical and human forces that work in combination to form and transform the world.

Giardia

A microorganism (bacteria) that causes stomach and intestinal illness.

Greywater

Greywater is the wastewater from washing machines, dishwashers, showers, baths and basins.

Grit

Small insoluble particles in wastewater such as sand, coffee grounds gravel, glass and food particles.

Groundwater

Water located beneath Earth’s surface filling the spaces between grains of soil or rock.

Hazard

Something that exposes us to the risk of harm.

Hydroelectric power

Electricity made from falling water turning turbine generators.

Hydrological cycle

The cycle of water between the Earth and the atmosphere powered by the Sun. Also called the water cycle.

Hydrological hazard

Hazard events originating in the hydrosphere from changes to the water cycle, like floods and droughts.

Hydrosphere

The area where Earth’s water is found in forms like streams, oceans, ice caps and water vapour.

Hypothesis

A predictive statement that can be tested.

Impurities

Unwanted substances such as sediment or chemicals which may need to be removed from water to protect public health and the environment.

Industrial discharge

Waste substances produced or left over during manufacturing that are discharged or released into waterways.

Infiltration

Water that soaks into the ground during and after rain.

Insoluble

A substance not able to be dissolved.

Intermittently Decanted Aerated Lagoons (IDAL)

A pond or tank where wastewater undergoes several treatment processes in rotation including sedimentation, biological treatment and clarification.

Irrigation

Supplying water to land to grow plant crops using a system of artificial channels, pipes, sprinklers and/or drippers.

Lithosphere

Earth’s outer rocky shell, including all the rocks and soil that cover the planet.

Litter boom

A floating device with a hanging mesh curtain used in creeks and stormwater channels to trap floating rubbish.

Liveability

An assessment of what a place is like to live in, using criteria such as environmental quality, safety, access to shops and services and cultural activities.

Macroinvertebrate

An animal that does not have a backbone and is large enough to be seen with the naked eye.

Membranes

Thin layers of material that allow only some substances from a solution to pass through them.

Methane gas

A simple hydrocarbon without colour or odour produced when microorganisms digest solid waste without oxygen present.

Microbiological

Relating to microbiology or microorganisms.

Microorganisms

Organisms that are too small to be seen without a microscope.

Mineral

A solid substance formed through geological processes that has a specific chemical composition, structure, and physical property.

Molecule

A group of at least two atoms held together by strong chemical bonds.

Monitoring

Observing and keeping a record of something.

Monochloramine

An organic chemical compound. Small amounts are commonly used as a water disinfectant instead of chlorine gas.

Multi-barrier approach

A process of managing land and testing water in catchments, reservoirs, water pipes, water filtration plants and taps, to protect public health and the environment.

Natural hazard

When the forces of nature combine to become destructive and have potential to damage the environment and endanger communities, like bushfires, floods and earthquakes.

Natural resources

Resources provided by nature.

Natural world

Relates to and includes phenomena in the biological and physical world on and beyond the Earth.

Nitrate

A chemical substance used widely in fertilisers, and contained in human waste from the digestion of proteins. Contains nitrogen which is a plant nutrient.

NTUs

Nephelometric turbidity units are used to measure the amount of material suspended in water making it cloudy (turbid).

Nutrient

A substance that provides nourishment, food or energy.

Organic matter

Material from something that was once living but has now decayed.

Organism

Animals, plants and other living things like fungi or algae. An individual animal or plant.

Oxygen

A gas without colour, taste or smell essential to plant and animal life.

Pathogenic

Able to cause disease.

Perception

People’s assessment of places and environments.

pH

pH is the scale used to measure the acidity or alkalinity of a substance.

Phosphates

A chemical substance used widely in fertilisers and detergents. Contains phosphorus which is a plant nutrient.

Phosphorus

An essential nutrient for plants, animals and humans.

Pollutant

Something that contaminates or degrades the environment making it impure or dirty.

Polluted

Contaminated with harmful substances.

Pollution

Any harmful change in the environment due to the release of contaminants.

Pore

A tiny opening or space that fluids pass through, like tiny spaces between grains of soil or tiny holes in a polymer membrane

Precipitation

Water that falls from the sky as rain, hail or snow. Also a chemical reaction occurring when two solutions react to form a solid (a precipitate), used in all forms of water treatment.

Rainwater

Fresh water that falls as precipitation from clouds.

Recycled water

Wastewater (sewage) that has been treated to such a level that it can be reused for non-drinking purposes.

Recycling

Collecting and processing a resource so that it can be used again.

Renewable resource

A resource that is replaced by natural processes at a faster rate than it is used.

Reservoirs

A built water storage area like a dam or tank that holds water until it is needed.

Reverse osmosis

A process where a solution is forced under pressure through a semi-permeable membrane, separating pure water from dissolved salts.

Run-off

Rainwater that runs over the Earth’s surface and into waterways rather than being absorbed into the soil.

Salinity

The presence or amount of salt in water and soil.

Screenings

Solid materials like plastic removed from wastewater by screens.

Scum

Any material that floats to the surface of wastewater during treatment, usually removed in sedimentation tanks.

Sediment

Materials of different sizes that sink or settle to the bottom of a sediment trap.

Sediment trap

A device that captures eroded or disturbed soil, often used at construction sites to protect water quality of a nearby waterway.

Sedimentation

Sedimentation is a physical wastewater treatment process used to settle out suspended solids in water under the influence of gravity.

Sedimentation tanks

Tanks where the process of sedimentation takes place.

Sensitive

Easily affected by slight changes in environmental conditions.

Septic tank

An underground tank used to treat wastewater through bacterial activity.

Sewage (wastewater)

The used water that goes down sinks, toilets and drains and into the sewerage system. About 99 percent of sewage is water. Also called wastewater.

Sewage overflow

This occurs when a wastewater pipe is blocked or flooded by heavy rainfall, resulting in wastewater overflowing into the environment.

Sewage (wastewater) treatment plant

A place that treats sewage, also known as wastewater.

Sewer

System of underground pipes used to transport wastewater.

Sewerage system

The network of pipes, pumping stations and treatment plants used to collect, transport and treat wastewater, then discharge the effluent.

Sludge

Solid matter that is removed during wastewater treatment. It can be processed into a material called biosolids.

Social connectedness

A measure of the number and strength of people’s social relationships with other people in the same place, or in other places via face-to-face connections or electronic methods. The opposite of good social connectedness is social isolation or loneliness.

Soluble

The ability of a substance to dissolve in another substance.

Solute

A substance that has dissolved in a solvent.

Solution

The mixture formed when a substance (solute) has dissolved in a solvent.

Solvent

A substance that is able to dissolve a solute to form a solution.

Special distribution

The location and arrangement of particular phenomena or activities across the surface of the earth.

SQIDs

Stormwater quality improvement devices (SQID) like a trash rack or constructed wetland that improve stormwater quality by removing litter, sediment and nutrients.

Stormwater

Rainwater that runs off hard surfaces like roofs and roads and is carried away by stormwater drains flowing into local waterways.

Substance

A material composed of specific chemicals.

Survival

To continue to live or exist, to stay alive, often by coping with harsh or dangerous conditions.

Suspended material

Small and light particles dispersed through water that do not sink to the bottom or float to the top.

Sustainable

Able to continue indefinitely without damaging the environment or depleting a resource.

Sustainably

To do something in a way that will not harm the environment or reduce resources. 

Sustainability

The pattern of activities that meet the needs of the present generation without harming the ability of future generations to meet their needs.

Temperature

How hot or cold something is as measured by a thermometer.

Testing

The process of working out the quality of something.

Topographic

Detailed description or graphical representation of land surfaces.

Total catchment management

Sustainable use and management of land, water, vegetation and other natural resources in a catchment.

Trade wastewater

Wastewater contaminated as a result of business activities that may contain pollutants such as suspended solids, grease and other chemicals.

Transpiration

The process in which water vapour is transferred from the leaves of plants into the atmosphere.

Trash rack

A metal grill placed across stormwater channels to collect rubbish and other pollution.

Treat

To physically or chemically process something.

Turbid/turbidity

Water that is cloudy or not clear, caused by suspended materials such as sediments or plankton.

Turbines

A machine powered by wind, water or steam to produce electricity.

Ultraviolet

Invisible radiation present in the ultraviolet range of light.

Upper catchment

The highest parts of a catchment where a waterway begins.

Urban

Relating to a town or city.

Urban areas

Areas with a higher population density than surrounding areas such as towns or cities.

Urbanisation

The process of economic and social change in which an increasing proportion of the population of a country or region live in urban areas.

Urban water cycle

The urban water cycle is the way water is collected, used and managed in an urban environment such as Sydney.

Validity

The extent to which the test and results measure what was intended.

Vapour

Fine particles of a liquid suspended in a gas such as air. Examples are fog, mist or steam. Another word for a gas.

Vegetation

The plant life of an area.

Viruses

A microorganism that reproduces inside the cells of living hosts.

Wastewater (sewage)

The used  water that goes down toilets, sinks and drains and into the sewerage system. Also known as sewage. About 99% of it is water.

Water cycle

The cycle of water between the earth and the atmosphere, powered by the sun. Also called the hydrological cycle.

Water cycle processes

The physical changes to water that change its state and geographical location. Eg evaporation, precipitation.

Water filtration plants

A place that filters and treats raw water to make it suitable for drinking.

Water recycling plant

A place where wastewater is treated to a high (tertiary) standard so that it can be recycled for a range of beneficial, non-drinking, purposes. 

Water scarcity

The lack of sufficient available water resources to meet demand.

Water table

The top of a groundwater reserve.

Weather

The conditions in the atmosphere like temperature, humidity, cloud cover, rain or wind at a particular place over a short space of time.