Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | november 2014 | 19 access issues when it needed cleaning. The eventual solution involved a tank with segmented rings, and a sha which is open to the air. Cleaning can now be done from the surface using hoses, with any excess solids pushed through the sump so that they will be pumped into the wetlands in the next storm event. The reed bed provides sufficient treatment to allow storm waters to flow back into the watercourses without compromising water quality. The FBA aeration system is energy efficient because it only needs to be switched on once a day, or when required in a storm event - a process that happens automatically. "When the pumps come on and the flow is delivered to the bed, aeration starts automatically, ensuring that any displaced effluent in the bed is well oxygenated and treated," explains Hawes. "But if there's no flow for a 24-hour period, then the blowers come on for a few hours every day anyway to keep the bed well aerated." This automation, and the fact that the system requires little maintenance beyond a visual inspection and an occasional filter change for the aerators, will make life easier for Scottish Water's operational team. "For the operator, the benefit is that you have an asset which is controlled and monitored using our telemetry system, and there's very little that can possibly go wrong," says Burns. "This is a site that probably doesn't need too much intervention." The construction phase of the project took around 15 weeks. Now complete, the site can treat around 230,000 cubic metres of water per year, giving it one of the largest treatment capacities in the UK. SEPA inspectors did not take long to pronounce themselves happy with the readings from the nearby burn when the project was completed in March. The site is also much more pleasing to the eye and to the environment than previously, with the wetland forming a new habitat for birds and other wildlife. Burns concludes: "This was a site that nobody had cared for for a long period of time, and we've returned it to a state where it looks great, reeds are growing and we've enhanced the environment as well. Most importantly, the output from the wetlands and the impact on the burn was much improved, and when samples were taken the regulator was very pleased with the results." For further info go to wwtonline.co.uk The completed reed bed is able to treat 230,000 cubic metres of water per year, giving it one of the largest treatment capacities in the UK • Perspectives eddie burns, project manager, Scottish Water "This was a site that nobody had cared for for a long period of time, and we've returned it to a state where it looks great, reeds are growing and we've enhanced the en- vironment as well. Most importantly, the output from the wetlands and the impact on the burn was much improved, and when samples were taken the regulator was very pleased with the results." Patrick Hawes, Consultant, Arm Ltd "Forced Bed Aeration of- fers higher performance and more consistent performance through aeration than other sys- tems. Reed bed systems can be event-driven and offer space advantages, and in Cowdenbeath this suited the site very well. We hope this will build confidence within Scottish Water in the use of this technology and naturally lead on to other applications across the region." construction, is able to be cleaned from above

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