Ramsey Sewage Treatment Works and the Vollan Pumping Station
Ramsey and Andreas now have a sewage treatment works at Balladoole, alongside the civic amenity site. Here the combined sewerage from both locations is pumped into a treatment works where it is treated by covered Integrated Rotating Biological Contactors (IRBC’s). The treated effluent then flows by gravity back down to the Vollan, where it passes into the sea via the existing sea outfall.
As a key part of this project, the Victorian infrastructure buried deep below the Vollan on the Mooragh Promenade in Ramsey was also replaced. The project started in November 2015 and was completed in 2017. It comprised building a new storage tank, wet wells and pumping facilities below the Vollan and a new pumping station and control room adjacent to the BMX track. The building was carefully located to be compliant with international BMX regulations for adjacent structures.
As part of the enabling works for the Vollan, the water supply to Royal Park was also enhanced which allowed old pipes running across the area to be redirected and rerouted. A new electrical substation was also installed on the site, providing a fall-back supply to that area of Ramsey and capacity for future developments.
The excavation for the Vollan storage tank went down into the ground over 12m, and exposed the alluvial gravel of past millennia from the Sulby river’s original route out to sea! Over 2.6km of sheet-piling was driven into the ground to support it whilst the tank was excavated. To keep it dry, 1.5 billion litres of tidal ground water was pumped away onto the beach during the four months the hole was open. At the end of the works, the original 1888 Victorian storage tank (which runs under the Vollan roadway) was decommissioned and the old pumping station at the northern end of the Vollan was demolished.
The Vollan site under construction
The sea outfall position, pipeline route up to Balladoole and the location old Vollan tank are shown.
Over 2,800 cubic metres was excavated at the Vollan, then 3,000 cubic metres of concrete poured (including 900 cubic metres to fill the old tanks) and 1.5 billion litres of ground water removed, using 12 borehole pumps like those seen on the left of the photo.
The new Vollan pumping station
At Balladoole 35,000 cubic metres was excavated, and over 3,250 cubic metres of concrete poured during the construction activities. Balladoole Excavations underway showing the IRBC supporting concrete structures and protruding sludge drain pipes.
The Balladoole IRBC tanks completed, drainage being installed and ground level being restored. Here 3,750 cubic metres of stone was added to the site, with 148 tonnes of steel reinforcement added – including 9,414 square metres of mesh reinforcement walls and hardstanding.
IRBC rotors being installed.
Each rotor has thousands of ribbed sectors giving around 5 acres of surface area for the biofilm treatment process to function. The rotor revolves at around 3rpm, with the lower half submerged in the effluent to be treated. As it rotates, the bacteria on the huge surface area consume the undesirables in the effluent.
IRBCs fully completed and under cover. The concrete surface is the finished path and road level – compare this to the photo above which shows those pipes just visible above the edge of the IRBC concrete retaining tank during site construction.