ACWA secures major MBR upgrade project for Center Parcs Woburn Forest
ACWA Services has been awarded a design and construction project by Center Parcs UK to upgrade wastewater treatment and reuse facilities at Center Parcs Woburn Forest in Bedfordshire.
This will provide increased balance tank capacity and process resilience to match the expansion of the village facilities including the construction of 57 luxury accommodation lodges at the Woburn Forest site, an increasingly popular UK short break destination, just an hour from London.
This is ACWA Services’ third contract for Center Parcs and follows the design and installation of the original wastewater treatment facilities at Woburn Forest, completed in 2014 and a similar project at Center Parcs Sherwood Forest in Nottinghamshire, completed in October 2016.
Each is based on ACWA’s MEMTREAT membrane bio-reactor (MBR) technology. This is a compact and visually unobtrusive wastewater treatment solution that provides a high quality effluent without the requirement for primary or secondary clarification and tertiary treatments associated with conventional activated sludge processes. Pure water from the process is discharged to the local watercourse via a water quality monitoring station or reused, following further treatment using reverse osmosis, to top up lakes and water features.
Work to further improve the Woburn Forest water treatment facilities began in November 2016 and is due for completion in autumn 2017, in time for the opening of the new lodges. This will include the construction of a new, much larger balancing tank with a capacity of 1,200 m3, ensuring a uniform flow of wastewater and stable operating conditions for the bio-reactors. The provision of a jet mixing system will maintain solids in suspension.
The existing balance tank will be converted to provide a third MBR tank, incorporating eight additional single deck submerged plate MBR modules. This will also be fitted with new air scour blowers to protect the membranes from fouling, plus new duty and standby pumps for return activated sludge (RAS) and surplus activated sludge (SAS). Adding this third MBR tank ensures further resilience and will allow maintenance to the other MBRs without interruption to the process.
Additional modifications to the plant, which is designed to provide a treatment capacity of 1,134 m3 per day, will include new forward feed pumps to transfer wastewater from the balance tank to the anoxic process tank, new tanker loading and unloading facilities for sludge disposal and ferric deliveries, plus a larger sludge holding tank.
A key challenge for ACWA’s design and installation teams is to maintain the operation of the current wastewater facilities whilst the modifications are carried out. The first phase will involve the construction of the new balance tank and associated equipment, adjacent to the existing plant. Once this is operational the existing balance tank will be decommissioned and converted to house the new MBR modules.
ACWA’s approach to use membrane filtration has a number of advantages for Center Parcs, not least a significantly smaller footprint than conventional processes, which is particularly important where space and site constraints are an issue. The ability to operate with a higher Mixed Liquor Suspended Solids (MLSS) compared to activated sludge processes also allows for a smaller process volume and helps to optimise the biological process within the bio-reactor, so minimising the volume of surplus sludge and consequent disposal issues. Operation is also straightforward and an MBR ‘clean in place’ (CIP) system to provide periodic chemical cleaning can be carried out without interruption to the process.
To date ACWA has designed, supplied and installed in excess of 40 MBR systems, including one of the world's largest MBR treatment plants at Al Ansab, in Oman.