Chemical Technology February 2016

The recycling of grey water by Carl Schonborn, PrEng

Grey water recovery and recycling systems have been providing sustainable water solutions for the urban environment for some time. A range of systems has been designed to make homes, offices and commercial undertakings more water-self-sufficient.

E nvirowater, a company based in Durban, special- ises in the design and installation of grey water treatment and recycling technology. The tests performed on the Envirowater technology according to the Australian Guidelines for Water Recycling, proved it was able to deliver treated and recycled water to the standards required by the Australian State of New South Wales Water and Energy’s “Guidelines for Manage- ment of Private Recycled Water Schemes”; the State of Queensland’s “Queensland Plumbing and Waste water Code”; and the EPA Victoria Guidelines for Environmental Management’s “Dual pipe water recycling schemes, Health and Environmental Risk Management” (Publ. 1015). Most of the solutions discussed in this article focus on solutions for the more demanding, commercial and multi- dwelling environments. They are designed for architects, hydraulic consultants and engineers, developers and hy- draulic contractors and plumbers and are aimed at helping them understand how it is possible to tackle the special requirements these environments present. Envirowater commercial grey water treatment (CGT) systems The CGT Series of products is designed as a packaged plant able to be tailored to the specific application required by the

end-user. It has been developed from the highly success- ful and well-proven single-dwelling system using the same core technology but can also be equipped with enhanced disinfection capability, control systems and remote man- agement systems. Common across all Envirowater’s systems is the ability to treat and recycle grey water to a high level of quality. Grey water can originate from showers, baths, basins and laun- dries but excludes wastewater from kitchens, dishwashers, toilets and urinals. The patented technology enables the safe re-use of the recycled water for a range of residential and commercial applications including cooling tower make- up, surface landscape irrigation, toilet flushing and water features. The Department of Water Affairs and Technology, South Africa (DWAF) regulates which of these applications are allowable and ensures an effective and reliable treat- ment process. There are four key steps to the process. 1 Pre-screening The pre-screening system uses an automatic self-cleaning mechanical screen to remove hair, lint and other coarse materials to prevent blockages and fouling of the system. Due to its unique design the pre-screen requires limited maintenance interventions and is able to operate effectively at high processing volumes.

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Chemical Technology • February 2016