Sydney Water Annual Report 2009
Statutory information: Glossary

Please select a letter






Activated carbon

Used to absorb dissolved organic matter from wastewater.

Algal bloom

Rapid growth of algae in surface waters due to an increase in nutrients such as nitrogen and phosphorus and availability of light.

Australian Drinking Water Guidelines

The guidelines summarise the criteria representing the basis for identifying acceptable water quality.



Solids from wastewater treatment are processed into products for beneficial uses, such as agriculture or forestry.



An area of land surrounding a dam or water storage. Rain falling over the catchment drains to the dam and may contain nutrients, minerals and contaminants collected from the land surfaces.


Parasitic protozoans occurring in warm-blooded animals. These organisms can occasionally find their way into the water supply. Disinfection and treatment processes normally inactivate or remove them from the water.



Artificial walls built to store water – mainly for domestic use or irrigation.


Department of Environment, Climate Change and Water.

Deepwater ocean outfall

A submarine tunnel or pipeline which carries treated wastewater away from the coast into deep ocean waters where it can be diluted and dispersed.


The amount of water that would be used if there were no limitations or restrictions on use.

Demand management

Strategies to help residential, commercial and industrial customers use water efficiently.


The process that removes salt from saline water to produce fresh water.


The chemical or physical process to kill organisms that are capable of causing infectious disease.

Drinking water

Water intended mainly for human use, but which has other domestic uses.



Every Drop Counts – water conservation programs for business and the community.


A waste product that is discharged to the environment, usually means treated wastewater discharged from sewage treatment plants.


Energy & Water Ombudsman NSW. A body that gives an independent way of resolving customer complaints about member water, electricity and gas providers.


Filtration (water)

A process for removing particles from water by passing it through a porous barrier, such as a screen, membrane, sand or gravel.



Parasitic protozoans that occur in warm-blooded animals. These micro-organisms can occasionally find their way into the water supply. Disinfection and treatment processes normally inactivate or remove them from the water.

Greenhouse gas emissions

Gases, such as carbon dioxide and other air pollutants that contribute to the greenhouse effect through fossil fuels being burnt, such as coal, natural gas or oil.


Hard and heavier solid matter removed from wastewater, generally inorganic.



Independent Pricing and Regulatory Tribunal. The independent body that oversees state regulation in the water, gas, electricity and public transport industries.


Controlled application of water for agricultural purposes through systems constructed to supply water needs not satisfied by rainfall.


Litre (L)

A measure of liquid volume.


Megalitre (ML)

One million litres.


An ongoing testing program to assess potential changes in circumstances.


Odour scrubber

A device for removing odours released during wastewater treatment.

Operating Licence

A licence issued under the Sydney Water Act 1994 that sets many of Sydney Water’s performance standards.


Animal or vegetable in origin.


Movement of water molecules through a thin membrane from an area of high concentration to an area of low concentration.


Rainwater tank

On-site storage to collect rainwater for beneficial use.

Recycled water

Highly treated wastewater for use in industrial processes, such as irrigation in agriculture, urban parks and landscapes, and household use, such as flushing toilets, car washing and watering gardens. It is not for drinking or personal use.


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


Organisations that set regulations and standards for Sydney Water to meet, eg the Environment Protection Authority and NSW Health.


An artificial body of water. Water is transferred from dams and treatment plants by gravity or pumping stations to a human-made water storage area, usually on high land. The water then flows through a system of mains and smaller pipes to homes, shops, factories, schools and public places.

Reverse osmosis

A process of removing salt and other organic and inorganic compounds from seawater. Molecules of pure water pass through the reverse osmosis membrane.

Risk assessment

Process of gathering data and making assessments to estimate short and long-term harmful effects on human health or the environment from exposure to hazards associated with a particular product or activity.



Sydney Catchment Authority. Manages and protects Sydney’s catchments and supplies bulk water to Sydney Water and various local councils.


Materials taken from wastewater by screening processes, such as timber, rags, plastic and condoms.


Soil or other particles that settle to the bottom of lakes, rivers, oceans and other waters.


The wastewater from homes, offices, shops, factories and other premises discharged to the sewer. About 99% of sewage is water.

Sewage overflow

Liquid that escapes from the sewerage system, as well as partially treated sewage that is discharged from a sewage (wastewater) treatment plant.

Sewage system

The network of pipes, pumping stations and treatment plants used to collect, transport, treat and discharge sewage (wastewater).


Solid matter that is removed during wastewater or water treatment. It can be processed into a material that can be beneficially used (biosolids).


Any individual or group that can affect or be affected by an organisation’s activities.


Rainwater that runs off the land, frequently carrying various forms of pollution such as litter and debris, animal droppings and dissolved chemicals. This untreated water is carried in stormwater channels and discharged directly into creeks, rivers, the harbour and the ocean.


Sewage treatment plant – a facility to improve sewage quality before discharge to receiving waters.


Trade waste

Industrial or commercial wastewater with significant potential contaminants usually set by agreements with trade waste limits.

Treatment (water)

The filtration and disinfection process.



Discarded, rejected, unwanted, surplus or abandoned substances. Does not include gas, water, wastewater, beneficially used biosolids and reuse water.


The dirty water that goes down the drains of homes and businesses and into the wastewater system. Also known as sewage.

Wastewater system

The system of pipes and pump stations for collecting and transporting wastewater from each property to the wastewater (sewage) treatment plant.

Wastewater treatment

Primary – the first stage of wastewater treatment where floating or settling solids are removed by screening and sedimentation.
Secondary – the second stage of wastewater treatment where dissolved fine organic solids are captured and removed.
Tertiary – the third stage in the purification of wastewater, largely where nutrients and any remaining suspended solids are removed. Effluent may also be disinfected.

Wastewater treatment plant

Wastewater treatment plants treat wastewater, also known as sewage, from the sewerage system. Once the waste is treated, it is either discharged to the environment or is recycled as effluent reuse.

Water demand

Total water use needs for drinking, agriculture, industry, recreation and gardening; seasonal and highly influenced by the weather.

Water filtration plant (WFP)

A treatment plant that improves water quality by removing impurities through filtration.

Water pumping stations

Stations that house mechanical pumping equipment used to lift water from lower ground to higher ground through pipes.

Water quality

Physical, chemical and biological measures of water.

Water reuse

The use of water more than once, following treatment of wastewater to an appropriate quality standard and delivery to the point of use.

Water supply system

The network of pipes, pumps and local reservoirs that deliver water from the water filtration plants.


All streams, creeks, rivers, estuaries, inlets and harbours.


A low-lying area often covered by shallow water, such as marshes, mangroves, swamps, bogs or billabongs. Rich in biodiversity, they store and filter water and replenish underground water supplies. Also effective in cleaning polluted water by reducing aquatic plant nutrients, suspended solids and oxygen demands.


Water Services Association of Australia.