Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | DECEMBER 2015 | 19 Project focus: wastewater treatment An aerial view of Clonakilty Wastewater Treatment Plant, County Cork. • Innovations ● Nereda combines the treatment characteristics of granular biomass with highly automated sequence batch reactors (SBRs) ● Its large, dense granules can settle up to ten times faster than conventional activated sludge ● The Clonakilty plant is the first Nereda plant in the world to be built underground original plant using significantly less energy and produces less sludge. The lower nitrogen and phosphorus content in the effluent brings to an end the problem of unpleasant odours in Clonakilty Bay. EPS has subsequently utilised the Nereda technology in two further applications for WWTPs at Carrigtwohill (30,000 PE) and at Lower Harbour (65,000 PE) for Irish Water. Both projects were evaluated on a whole life cost basis, with the Nereda process found to be the most economically viable for Irish Water. Royal Haskoning DHV's Global Director for Water Products and Innovation, Mr René Noppeney is proud that EPS has joined the global network of Nereda partners. "Together we are providing a sustainable solution to towns and cities facing challenges associated with urbanisation and the demand for good sanitation," he said. footprint size limitations, and the planning restrictions on the site. In the new process the biomass responsible for biological removal of biodegradable organic compounds and nutrients from the wastewater consists of large dense granules, approximately 4mm in diameter. These granules settle up to ten times faster than conventional activated sludge, thereby reducing the reactor volume required for biological treatment. The granules contain an outer aerobic zone and an inner anaerobic core, allowing biological removal of biodegradable organic compounds and nutrients to take place within a single reactor. Biological phosphorus removal reduces chemical dosing requirements and sludge volumes. The larger denser granules are inherently more stable than activated sludge and make for a more robust treatment process. Irish Water's Clonakilty plant, completed in August 2015, has been completely overhauled and the Nereda technology has quadrupled its capacity to 20,000 population equivalent (PE). It treats the effluent to a far higher standard than the

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