Water Sources: Recycled Water

recycled water trigger nozzle and hose

Continuing our series on water sources, we are looking at recycled water but before we can do that, we first need to know about wastewater. Wastewater is water that has been used by businesses and households and is then treated at a wastewater treatment facility. Perhaps because it has been inappropriately named or just because of the smell, wastewater has traditionally been quickly siphoned away, treated and returned to the environment. Today, water providers around the world are catching on to more ways to make the most of wastewater.

Waste Water Treatment Plant

What is recycled water?

Recycled water is wastewater that has been treated to a quality suitable for reuse. In Victoria, recycled water is broken down into classes A – D which make it easier to figure out the quality of the water and what it can be used for. Class A is the highest quality and can be used for a range of purposes. There are similar schemes in other states, where Class A+ is the highest quality of recycled water for non-drinking purposes. Water recycling also happens at a household level, where water from the washing machines, showers and baths is captured and reused as grey water for watering the garden or treated for other purposes.

What can recycled water be used for?

Depending on the quality, recycled water can be used for a wide range of purposes. Class D water is fairly limited, and can only be used for watering non-food crops. Class A water can be used for raw food crops, as well as piped to residential areas for use in gardens, toilets and even washing machines. Class A water is not suitable for drinking, cooking, bathing or showering, filling pools, spas or air conditioning, or filling water toys like water pistols.

Recycled water is also used for watering parks and gardens, sporting fields, or providing water for power stations.

While controversial, recycled water can be treated to a level that is safe for drinking and there are a number of locations around the world where this occurs. Usually the recycled water is dispersed in another water source, like a fresh water reservoir. This occurs indirectly in Australia, along the Murray River, where treated river water is used as drinking water in local towns. The town’s wastewater is treated and returned to the river, it then flows on to the next town where it goes through the same process.

Recycled water for drinking may seem ‘out of this world’ and in one case, it literally is! Astronauts on the International Space Station (ISS) recycle 93% of their water for everyday use.

Check out this video about water recycling on the ISS

How is recycled water used?

Water providers in Australia provide recycled water through a number of methods. Tanker trucks may pick up the recycled water from the wastewater treatment plant for delivery to farms, sporting grounds, industry or use by local councils in parks and gardens.

A number of recycled water projects are also using sewer mining, which involves connecting to an existing sewer and then treating that wastewater on site.

A number of water providers have invested in providing Class A recycled water to residential developments as a third pipe system (the other two pipes are for drinking water and wastewater). This third pipe for recycled water is purple and can be connected for gardens, toilet flushing, and in some cases, clothes washing.

Recycled Water Tap

Here are some examples of recycled water projects that are happening around Australia:

What are some of the benefits of recycled water?

  • It provides an attractive alternative water source in locations that don’t have access to fresh water, desalination and have low rainfall.
  • It reduces the amount of treated wastewater that is returned to the environment.
  • Recycled water is a more certain supply for watering gardens when faced with water restrictions.
  • Frees up fresh water for environmental flows.

What are some of the issues with recycled water?

  • Building a third pipe system for recycled water to every household is expensive and only really practical for new home developments. Recycling water back into the potable system would be a far more affordable alternative.
  • Because recycled water can require more stringent treatment than potable water, the water provider ends up subsidizing the cost for it’s recycled water customers.
  • The yuck factor of using recycled water in the potable system is a major barrier for most communities.

Further information

Would you ever consider drinking recycled water that had been treated to drinking quality?