Grey Water Recycling

Re-Use Of Waste Water

Industrial Grey Water Recycling refers to water that is recovered as a by-product of manufacturing, cleaning and other uses in the factory environment and then reused in the same functions or other purposes like irrigation. It usually contains a variety of contaminants that need to be measured to ensure that re-use does not damaged plant and equipment.

Care must also be taking to ensure that the recycled water does not contain harmful toxins that may present a health and safety risk to humans and the environment. These contaminants typically include bacteria, suspended and/or, dissolved solids, acids, alkalises and synthetic bacteria. The Water Act (1998), states that it is illegal to discharge contaminated industrial wastewater to the sewerage and storm water systems.

The Grey Water recycling system is made up of one or more tanks that includes a filtration system. The size is dependent on what process is needed to recycle the water. A well designed piping system serviced by a pump will ensure that the system works economically. Depending on the water flow rate, some systems employ mechanical filtration to remove the suspended dirt to protect downstream equipment such as valves.  If needed, additional treatment to remove or protect the Greywater may include sand filtration, bleach, ozone or UV light.

What You Need To Know:

Depending on the type of system and the cost of water in the region, a payback period of two to three years is achievable

Some Greywater systems may need to add chemicals to kill harmful microorganisms or may need special treatment to remove harmful toxins

Design and layout of the piping in the grey water system will directly affect performance

Total consumption can be dramatically reduced

In the future, the regional & local government may require permitting/monitoring of these systems

Regulations require that mixed wastewater is discharged to the appropriate drain system (i.e. storm or sanitary drains)

Grey water recycling systems also include biological systems (plant systems as treatment ponds, constructed wetlands, living walls, etc)

It is not advisable to include any water containing fat deposits (from staff kitchens or canteens)

Storage tanks can be below/above ground

The system requires maintenance and monitoring which includes periodic water quality testing

The type, design and layout of a factory grey water recycling systems is dependent of what type of manufacturing process exists and the waste water content that exists after the manufacturing process has taken place. Each system must be customised to suite specific factory needs

The diluted residues, soaps etc in the water can provide useful sulphates and nitrates which some experts say is more beneficial to the garden than clean tap water

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