Water & Wastewater Treatment Magazine
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Developing resilience This month's Innovation Zone focuses on rainwater harvesting, which can make buildings more water efficient and ensure the best use of water resources By Robin Hackett Innovation Zone Rainwater harvesting C limate change threatens to not only limit water resources but to also bring about more frequent flooding. Rainwater harvest- ing can help on both fronts, taking rainfall and keeping in storage tanks ready for use where necessary. There are products avail- able on the market options that make use of data analyt- ics – such as Waterscan's Intellistorm and StormHar- vester, which featured in Oc- tober's Innovation Zone – to anticipate storms and provide added flood protection. Here, we've picked out a selection of rainwater harvesting tech- nologies that offer a variety of other advantages. FlushRain (FlushRain) The FlushRain rainwater harvesting system can be easily retrofitted to properties by placing reservoirs on the downpipe beneath gutters, with the water then used for flushing toilets or for laundry systems. The reservoirs – known as collection cartridges – contain a hosepipe fitted with a water sensor and filter. When the sensors indicate that all reservoirs are full, a computer switches on a pump that sends the water through the hoses to a storage tank situated in the lo of the property, passing through a further filter along the way. Multiple storage tanks can be placed within the lo to maximise the amount of water available for reuse, with a site inspection required to determine the location's load- bearing capacity. FlushRain also makes use of sensors to disable the pump if the temperature is freezing or the storage tank is full, and there is a mains back-up system built-in. It is less expensive than many alternative rainwater harvesting systems, and Severn Trent has installed it in some properties within its area. RainSafe (H2Ozone) RainSafe takes water from rainwater harvesting systems, wells and boreholes – and even existing municipal supplies if necessary – and treats it to drinking water standards, potentially providing the user with 100 per cent of their supply needs. Suitable for use in residential, commercial and hospitality settings, RainSafe – which is around the size of a standard European fridge-freezer – can supply up to 7,000 litres of purified water per day and offers low energy consumption at only 0.5kW/hour. It uses H2Ozone technology to provide chemical-free purification, passing the source water through a filter that removes any dirt above 5 microns before it undergoes a UV and Ozone treatment stage. Water is then held in storage and monitored – with the option to view information online through WiFi or 3G – to ensure it remains safe to drink before being drawn back through a carbon filter when required for use. RainSafe was certified by KIWA in September 2016 and has been found to comply with the microbiological World Health Organization/ Drinking Water Directive parameters in more than 50,000 tests, with 25,000 of those carried out independently. WaterFence (WaterFence) Created by US teenager Steven McDowell as part of a 9th grade science project, WaterFence was designed to tackle California's drought problem and has since gone on to earn recognition at a number of award ceremonies. The system collects rain from the roof of a home or office building through screened gutters that keep out debris and redirects the water to the fence. The water is then retained there in a closed system that prevents contamination from biological growth, bugs or rodents, and a hose or drip system can be used to make use of the stored water when required. The fence sections can each hold 908 litres of water and have a life expectancy of approximately 30 years. Designed to be cheaper than underground storage and more attractive than above- ground options, the fences can be customised to offer a wood, faux stone or natural appearance and are made from 100 per cent recyclable (HDPE) polyethylene. GOAL 6 WATER CONSUMPTION 26 | FEBURAUY 2019 | WWT | www.wwtonline.co.uk