Wastewater treatment specialists, ATAC Solutions, provided an innovative solution to ensure complex repairs to a failing sewerage plant were completed without disruption to a tranquil area of countryside.
Its engineers were called to an area of outstanding natural beauty in the New Forest, location of a sewage treatment works owned by Southern Water. The site, which is adjacent to an idyllic river walk between Beaulieu village and Buckler’s Hard, required refurbishment to maintain its long-term reliability.
With the plant’s units situated at ground level or below to minimise visual impact, engineers faced a challenge in rectifying the problem without causing unsightly disruption. The site, built to serve a population of about 250 people, compromised underground septic tanks, a lift pumping station and a flow-split chamber which channelled flow towards a Rotating Biological Contactor (RBC) or a Submerged Aerobic Fixed Film Reactor (SAFF) before passing through a conical humus tank. Designed to be non-nitrifying, the plant does achieve some nitrification.
Following intense investigations, the RBC was found to have expired and required considerable repair. However, due to the unit’s age, spares were unavailable. Rather than remove the below-ground, concrete-encased unit and risk disturbing the scenic surroundings, engineers decided a more practical, and aesthetically-pleasing solution would be to replace the malfunctioning equipment inside. Process calculations were run and a design was developed to manufacture two, self-contained SAFF modules equal to 18m3 total media volume. The units were constructed off-site before being lifted into the prepared RBC body. Blowers were also replaced as part of the upgrade. These are now providing air for both sections of the plant and operating with more energy efficiency than previously.
To ensure the site maintained its regulatory compliance throughout repairs, ATAC supplied its own temporary treatment equipment. The entire refurbishment was completed in two months, resulting in a plant with excellent effluent compliance; long-life projection for Southern Water, and an unspoilt view for members of the public