London Strives To Make Olympics Sustainable Through Water-Reuse System

July 26, 2012

Featured, Technologies

The Old Ford Water Recycling Plant will provide recycled water for nonpotable use during the 2012 Olympic Games. Photo courtesy of London 2012

The Old Ford Water Recycling Plant will provide recycled water for nonpotable use during the 2012 Olympic Games. Photo courtesy of London 2012

The 2012 Olympic Games are scheduled to begin officially with the opening ceremony on July 27. But while all eyes will be on the sporting events, a nonpotable-water-reuse system will be an unsung hero of this year’s games.

The Olympic Park in London is ready to welcome nearly 250,000 international visitors each day during the games, said Holly Knight, head of sustainability for the Olympic Delivery Authority (ODA; London). This is due, in part, to the Old Ford Water Recycling Plant, which began operating in November.

The new plant provides water for irrigation and toilet flushing, as well as for the cooling towers of a combined cooling, heat, and power (CCHP) energy center. Also, as the first nonpotable-water-reuse treatment system in the United Kingdom, the plant paves the way for future water-use projects, Knight said.

“It’s really just a stepping stone for investigating whether or not this is a real option for London in the future,” Knight said. “[Now], there’s a new set of water quality standards and a process to engage with the regulators that wasn’t in place before.”

Setting a goal for sustainable water use

ODA instituted a sustainable water strategy with the goal of reducing potable water use by 40% in the park. The first step was installing water-efficient plumbing fixtures, such as low-flow toilets and water-saving faucets, Knight said. But this only achieved an 18% reduction, according to the ODA report Learning Legacy: Lessons learned from the London 2012 Games construction project.

After conducting a feasibility study into alternative water supply options, ODA determined that a large-scale nonpotable water solution was needed to reach the 40% goal. Early studies had ruled out wastewater reclamation because of the risk and cost constraints, the report says, but Thames Water (Reading, England) offered to become a partner on the project if ODA reconsidered wastewater reclamation.

“Having them manage all the technology took away a huge amount of that risk,” Knight said. Each organization invested €5 million to fund the joint project.

Creating a system that treats wastewater for nonpotable reuse

The Old Ford Water Recycling Plant pumping station delivers nonpotable water to permanent structures in the Olympic Park to flush toilets and irrigate the landscape. Photo courtesy of London 2012
The Old Ford Water Recycling Plant pumping station delivers nonpotable water to permanent structures in the Olympic Park to flush toilets and irrigate the landscape. Photo courtesy of London 2012

In 2008, the design process began with ODA managing the pipe network and Thames Water managing construction of the treatment plant. But because this is the first plant of its kind in the United Kingdom, there were no standards to follow.

The main requirement was to supply water to the energy center’s cooling towers, Knight said. The center was created to supply a sustainable source of energy for heating, cooling, and electricity in the Olympic Park through CCHP powered by natural gas and a boiler using wood chips as a fuel to generate heat.

“Our energy center is actually the largest consumer of water on the park,” Knight said. And to reduce the amount of water needed in the towers, water quality had to be higher quality than groundwater, the report says.

So, ODA and Thames Water developed water quality parameters that aligned with the U.S. Environmental Protection Agency’s Urban Reuse guideline. The resulting high-quality reclaimed water is suitable for both urban reuse and the energy center, the report says.

To achieve this quality, the plant relies on a membrane bioreactor (MBR). First, wastewater is treated in septic tanks. Then it passes through 1-mm screens and is treated by an MBR, the report says. Next, 0.04-μm ultrafiltration membranes remove solids and pathogens, and a conventional granular activated carbon process further treats the water. The effluent is disinfected with sodium hypochlorite before being sent through the nonpotable-water-distribution network, the report says.

To ensure a consistent supply of wastewater, the reuse plant takes wastewater from the nearby Northern Outfall Sewer, the main system collecting wastewater from northeast London. It was designed to achieve an average flow of 0.574 ML/d, with peak storage of 0.813 ML/d.

Water-saving features combine to exceed original goals

In addition to being used in the energy center, reclaimed water is used to flush toilets and irrigate the Olympic Park’s 100 ha. “One of the most beautiful things about the London 2012 Olympic Park is the parklands and greenery,” Knight said. “So, this protects us against drought.”

Irrigation provides a large payback on investment, because London is a water-scarce region which experienced drought throughout the spring, Knight said. “We’ve invested hundreds of millions [of euros] in landscape works and redesign of habitat,” she said. “It’s a large possibility that some of that might not have survived if we hadn’t had the wastewater treatment plant to supply the irrigation water.”

Additionally, the park’s aquatic center saves water. It has a filter backwash system that collects water in pool filters, treats it through its own onsite treatment system, and uses it to flush toilets.

When combined, all of these water-saving steps have enabled ODA to exceed its original goals; potable water use has been reduced 58%, the report says.

Research and community education commences after the games

Artistic impression of the Old Ford Water Recycling Plant show how the facility was designed to blend in with the natural environment. Photo courtesy of London 2012

Artistic impressions of the Old Ford Water Recycling Plant show how the facility was designed to blend in with the natural environment. Photos courtesy of London 2012. Click for larger images.
Artistic impression of the Old Ford Water Recycling Plant show how the facility was designed to blend in with the natural environment. Photo courtesy of London 2012

To achieve community and environmental organization acceptance, the Old Ford Water Recycling Plant was constructed with aesthetically appealing architecture and landscaping. It includes a “green” roof, a butterfly pond, and wildlife trails. Following the games, the Olympic Park will be open for public use.

“London Wildlife Trust will organize nature walks,” Knight said. The walks will be combined with an educational component in the energy center’s visitors’ center to engage and educate the public, she added.

Also, for 7 years after the games, Thames Water will operate the plant and gather research on its operation, Knight said. Thames Water will examine operational costs and conduct cost-effectiveness studies, she said. “After that 7-year period, they’ll do a review of the operational process of the technology … and decide whether or not they want to upgrade it, or close the plant down, or switch to a different type of treatment.”

Jennifer Fulcher, WEF Highlights

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