UK's first eco town harvests the rain with Graf UK

Published:  16 September, 2016

Ninety one brand new, true zero-carbon homes in Bicester, Oxfordshire, have been fitted with complete rainwater harvesting and stormwater management systems from Graf UK.

The homes are the first to be built in the UK’s first ever eco town, North West (NW) Bicester, as part of the Elmsbrook phase of the project. On completion, Elmsbrook will comprise a total of 393 highly energy-efficient, true zero-carbon homes. These include a mixture of privately owned houses and flats, as well as affordable housing, all of which are fitted with extensive efficiency measures, such as solar PV panels and triple glazing. To reach Code for Sustainable Homes Level Five standards, developers A2Dominion needed to limit each property’s potable water consumption to just 80 litres per person per day. As well as reducing pressure on the mains supply, flooding protection was also a key concern – so they enlisted the expert help of civil engineering consultancy Infrastruct CS Ltd to specify a water management solution.

The Infrastruct team worked with Graf UK to design, install and commission a complete rainwater harvesting and stormwater management package for each of the 91 properties consisting of a 1,500L Platin tank and a soakaway made of Rain Bloc modules - helping them achieve Code for Sustainable Homes Level Five standards and minimise flood risk.

Tim Trotman, director at Infrastruct, explains: “Graf UK is a company that’s local to us, and we’ve worked with them several times before – so we knew they could help us find the right water-saving solution to meet the needs of this unique project. The Platin tanks sit out of sight underground, and use submersible pumps to feed collected rainwater into a header tank in the loft of each home. The header tanks then gravity-feed the water to the properties’ bathrooms, where it is re-used for sustainable toilet flushing.

“The system is engineered to use hardly any mains water, only diverting to the mains supply if the tank is empty (for example, after a particularly hot, dry spell). This not only helps save water, but also keeps bills down for homeowners and tenants. To manage excess water in the event of heavy rainfall, each rainwater harvesting system has its own soakaway made up of Graf’s Rain Bloc modules. These stormwater tanks all feed into a central soakaway, where water is gradually released back into the underlying ground conditions in a controlled way – reducing pressure on the drains and minimising flood risk.”

Elmsbrook at NW Bicester is the only development in the UK to meet the government’s strict requirements for the delivery of eco towns set out in the Planning Policy Statements (PPS1). Elmsbrook is set to boast a primary school, a community centre, an eco-pub and an eco-business and retail centre. Once finished, NW Bicester as a whole will consist of up to 6,000 sustainable homes.

Steve Hornblow, project director at A2Dominion, adds: “We’re proud to be leading the way with the country’s very first eco town. Our hope is that this innovative project will now set the standard for the development of many more sustainable communities in the UK. Environmental integrity is at the heart of NW Bicester – and rainwater harvesting plays a key role in ensuring we are managing natural resources to the best of our ability. The Graf UK systems mean Elmsbrook residents are now benefitting from cost-effective, efficient rainwater harvesting, as well as a solution that helps protect against flooding.”

Engineered with ultimate ease of installation in mind, the unique flat shape and lightweight design of Graf UK’s Platin rainwater tanks means they are groundwater-safe and can be buried at significantly shallower depths than traditional cylindrical cisterns – allowing for up to 80 per cent less digging. The tanks also feature integrated, self-cleaning filter technology for minimal maintenance, as well as wide tank domes for simple filter assembly during installation and straightforward ongoing maintenance – ensuring full peace of mind for end-users.

Graf UK’s Rain Bloc stormwater modules are made from expertly designed plastic cells that fit seamlessly together to build tailor-made, crate-style soakaways. The Rain Bloc black models used at Elmsbrook have a lorry-bearing capacity of 60 tonnes with a 500 mm earth covering. Weighing just 19 kilograms, the modules are also easy to install and are quick to link together using simple connectors.

Kevin Reed, national specification manager at Graf UK, concludes: “It is an absolute privilege to be involved in such a pioneering project. With extreme weather conditions becoming increasingly common in the UK, demand for rainwater harvesting systems that can be combined with stormwater management is on the rise. At Graf UK, we’re committed to offering cutting-edge solutions that are fit for the future – designed with long-term performance and simple, ongoing maintenance in mind. The Elmsbrook development is indeed the perfect example of how RWH systems can be effectively bolstered to provide effective SuDS alongside their harvesting capabilities.”

For more information about Graf UK’s extensive water management portfolio – including rainwater harvesting, stormwater management and wastewater treatment solutions – visit: www.grafuk.co.uk or call 01608 661500.

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