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Are you considering setting up a water recycling system?

This article serves as an initial reference for business customers in Australia looking into water recycling projects as an alternative water source, including councils, businesses, sports clubs, urban irrigators, land/property developers, and industrial entities.

For residents interested in water efficiency, options like rainwater tanks, greywater recycling and On-site wastewater systems that recycle blackwater/wastewater, like a septic system, might be worth exploring.

Firstly, it may be worth defining precisely what recycled water is.

Recycled water has previously been used in various areas, including bathrooms, laundries, kitchens, and businesses. This water undergoes cleaning, treatment, and purification processes to ensure it meets the safety and quality standards required for its intended re-use.

In Australia, recycled water is classified based on its quality and intended use. The classifications help manage how recycled water is handled, distributed, and utilised, ensuring safety and efficiency. The guidelines are outlined by the Australian Guidelines for Water Recycling.

Here are the primary classes of recycled water in Australia:

Class A Recycled Water: 

Class A recycled water is the highest-quality recycled water in Australia. It undergoes advanced treatment and disinfection processes to reduce pathogens and contaminants to very low levels. The treatment typically involves multiple stages, such as ultrafiltration, reverse osmosis, advanced oxidation, and high-level disinfection.

Here are the key characteristics and uses of Class A recycled water: 

• Safety and Quality: Class A recycled water meets stringent quality standards, making it suitable for various uses, including those involving close human contact.
• Uses: It can be used for a variety of purposes, including:
  • Urban residential purposes, such as toilet flushing and garden watering directly accessible to households.
  • Irrigation of crops that are eaten raw, parks, sports fields, and school grounds where there is a high likelihood of human exposure.
  • Industrial processes that require high-quality water.
  • Recreational uses, such as in decorative fountains and water features where public contact is possible.
  • As well as for all the uses allowed for Classes B, C and D

Class A recycled water is the highest quality available and suitable for a wide range of applications, including those involving direct human contact. These include clothes washing, closed-system toilet flushing, garden watering, and firefighting. Additionally, it can be used to irrigate food crops consumed raw or sold to consumers, either uncooked or processed, as well as for all the uses permitted for Class B, C, and D recycled water.

Because of its high quality, Class, A recycled water plays a significant role in water management strategies, particularly in urban and agricultural areas, helping to conserve freshwater resources.

Class B Recycled Water:

Class B recycled water has undergone significant treatment but not to the extent of Class A water. It is treated to a standard that makes it suitable for a range of uses where there is less human contact compared to Class A recycled water.

Here are the key aspects and uses of Class B recycled water:

• Treatment Levels: Class B water is treated to remove a substantial amount of contaminants and pathogens, but the treatment is less intensive than that for Class A water. The treatment often includes secondary processes such as biological treatment and disinfection.
• Safety and Quality: The quality of Class B recycled water requires some restrictions on its use, primarily to avoid direct contact with humans.
• Uses: This class of recycled water is generally safe for:
  • Irrigation of non-food crops such as pasture and fodder.
  • Irrigation of public parks and golf courses where public access is restricted or unlikely during irrigation.
  • Dust suppression in construction and industrial sites.
  • Certain industrial processes where water quality is not critical to the process or product.
  • As well as for all the uses allowed for Classes C and D

Class B recycled water is suitable for irrigating sports fields, golf courses, and land used for grazing dairy cattle. It can also be used for industrial washdown purposes, in addition to all the applications allowed for Classes C and D. However, its use comes with restrictions regarding human contact to ensure safety.

Class B recycled water is an important resource for managing water efficiently, particularly in agricultural and industrial applications and urban environments, where it can help reduce the demand for higher-quality potable water.

Class C Recycled Water:

Class C recycled water is suitable for uses with minimal human contact. It undergoes treatment processes to ensure it is safe for specific applications, although it is less rigorously treated than Class A and Class B recycled water.

Here are the key characteristics and common uses of Class C recycled water:

• Treatment Levels: Class C water treatment typically includes secondary treatment methods such as biological processing and some level of disinfection. The treatment removes significant amounts of organic matter and pathogens. However, the water might still contain higher levels of contaminants than Class A or B water.
• Safety and Quality: Class C water is generally considered safe for uses that do not involve close human contact or the potential for water to affect products consumed by humans.
• Uses: The typical applications for Class C recycled water include:
  • Irrigation of non-food crops such as flowers, some types of trees, and fibre crops.
  • Irrigation of pastures grazed by animals not producing milk for human consumption.
  • Industrial uses where water quality is not critical.
  • As well as for all the uses allowed for Class D

Class C recycled water is suitable for several applications, including the irrigation of crops intended for cooked or processed human consumption, such as wine grapes and olives. It is also appropriate for watering livestock grazing areas and fodder crops. Additionally, Class C recycled water can be used to irrigate human food crops grown more than a meter above the ground and consumed raw, including apples, pears, table grapes, and cherries.

Local councils may utilise Class C water for designated purposes. However, there are strict limitations regarding human contact to ensure safety.

Class D Recycled Water:

Class D recycled water is the lowest quality of treated recycled water in Australia, suitable for very specific uses where there is no human contact. The treatment process for Class D water typically focuses on basic contaminants removal and some level of disinfection, but the water retains higher levels of impurities compared to the higher classes.

Here are the key aspects and uses of Class D recycled water:

• Treatment Levels: The treatment for Class D water generally includes primary and some secondary treatment processes, which may involve basic sedimentation, biological processes, and limited disinfection.
• Safety and Quality: Due to its lower quality, Class D water is intended for uses that do not involve human contact. It is considered safe within its usage restrictions but is not suitable for applications that might expose humans directly to the water.
• Uses: Typical uses for Class D recycled water include:
  • Irrigation of commercial forests.
  • Environmental restoration projects where human contact with the water is unlikely.
  • Dust suppression on roads and construction sites.

Class D recycled water undergoes the least rigorous treatment compared to the other classes and is designated for specific non-food applications. It is suitable for irrigating non-food crops such as instant turf, woodlots, and flowers. Class D recycled water provides an important option for resource management, particularly in sectors like forestry and construction, helping to preserve more treated water for uses that require higher quality standards.

Summary

In conclusion, understanding the classifications and uses of recycled water is crucial for anyone considering implementing a water recycling system in Australia. This article has provided an overview of the types of recycled water—Class A, B, C, and D—each defined by its treatment level and suitability for various applications.

These classifications ensure that recycled water is safe and effectively utilised across different sectors, including residential, agricultural, and industrial settings. For business customers such as councils, sports clubs, and developers, recognising these distinctions can help in making informed decisions about water management strategies. Additionally, residents interested in water conservation have viable options like rainwater tanks, greywater systems and Home Sewage Treatment Plant (HSTP) to consider.

Overall, with proper understanding and implementation, recycled water can serve as a valuable resource, contributing to sustainable water management practices in Australia.