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Development and commercialisation of cost effective, easy to use, fit and maintain domestic greywater reuse system

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Greywater recycling reduces drinking water usage

Wastewater from showers and baths (tubs) is low in pollutants and thus high in potential for reuse. New technology exploiting that potential promises a 30 % reduction in domestic water consumption with benefits for consumers, industry, and the environment.

Climate Change and Environment

Climate change and growing global populations are placing increasing pressure on the world’s water supply. According to WHO, water scarcity already affects four out of ten people worldwide. Among its many initiatives for improved water management, the UN has targeted a reduction in daily household water consumption to as low as 119 litres per person, compared to a current sector-wide average of 141 litres. The EU-funded project Aqua Gratis has delivered a simple and inexpensive solution that promises a 30 % reduction in domestic water consumption, exceeding UN targets. Exploiting the ‘grey’ area Greywater is wastewater from baths and showers that is uncontaminated by toilet water/black water. Aqua Gratis innovators focused on recycling this water to simultaneously address the water supply problem and reduce the amount of domestic wastewater for treatment. Researchers developed a novel three-tank water treatment system that is concealed in the walls behind a downstairs toilet. Gravity delivers greywater from sources throughout a home to that toilet using existing plumbing. The multi-tank design allows debris to settle and traps floating debris. In addition, treatment of the water using an organic biocide prevents odours while protecting the environment from harsh chemicals such as bleach. Further, according to project coordinator Carolyn Hogg: “The integration of innovative, internal, self-cleaning, back-flushing filters results in the water quality being over and above the British standard BS8525.” Since the system is sealed and concealed, the noise from water flow is minimal. Smart metering further increases water management efficiency and cost savings. Finally, remote monitoring capability supports the annual maintenance programme. Aqua Gratis, as the system is called, can provide water to up to four toilets in a single house, eliminating the use of drinking water for toilet flushing. There is no comparable product available in the European market. Homes, commercial properties, and beyond The Aqua Gratis consortium is planning installations in new homes, inherently reducing costs associated with retrofit. The cost is estimated at less than EUR 1 000 for new homes and will be even lower when production volume increases. “The genius is in the simplicity of design – a system with excellent functionality and easy manufacturability making it ready for mass production from the start,” Hogg points out. Aqua Gratis will not only benefit individuals, developers, and the environment but also the water industry. Recently, western regulators started increasing pressure on water companies to address the water scarcity issue. Water companies stand to benefit significantly from Aqua Gratis. For example, among the 22 English water companies, Ofwat, operating in England and Wales, has financially rewarded the successful business models of the top 3 companies while putting the bottom 4 on notice. The measures include innovation and reduction in per capita consumption. Following a successful launch in the new-build housing market, expect to see Aqua Gratis in the commercial building and retrofit markets as well. A spin-off product, a smaller model for the hotel ‘pod’ market, will accommodate prefabricated bathrooms built off-site and then installed in modular construction.


Aqua Gratis, toilet, wastewater, domestic, water consumption, greywater, recycling, retrofit, biocide, multi-tank

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