FP McCann Precast Concrete Tank installed for Bio treatment of waste wash water
Site: Blue Bell Hill, Kent
Contractor: Wilcomatic Ltd
Client: Big Motoring World
FP McCann has supplied a large 15 cubic metre precast concrete tank for installation at a new car sales facility in Kent. The 22 acre site is being developed at Blue Bell Hill, Aylesford by the Big Motoring World Company. Once completed, some 20,000 vehicles a year will pass through the forecourt.
Part of the development includes an on-site vehicle washing plant and below ground bio-pit designed to capture and treat waste water for re-circulation. Croydon based Wilcomatic Ltd are installing the car wash system and have adopted a precast concrete tank design for the bio-pit. German based Wasserschmidt gmbh are the designers of the biological washing system and recommended FP McCann for be precast tank supply in the UK.
Dirty water is steadily channelled into the tank and passes through two holes cored in the two internal weir walls. Heavy sediments fall to the bottom of the first phase catchment area in the tank and the semi-clean water passes through into the second and third phase catchment areas. Micro bugs are introduced in the second and third phases which feed on the waste particles setting up a biological self-sustaining eco system. To aid the biological process, aeration mats are installed in the bottom of the tank. The water then finally passes through a separate fine filter system to be re-used in car washing plant.
The 15 cubic metres tank footprint itself measures 5.80 metres long by 2.80 metres wide with a height of 2.34 metres. Each of the 200mm wide internal weir walls measures 2.14 metres high. Completing the tank is a single cast lid section 5.40 metres long, with 6 access openings measuring 600mm x 600mm.
From start to finish, the tank was installed in 2 hours, excluding civils preparation and backfilling.
Commenting on the installation, Business Development Manager for Wilcomatic, Richard Morrison says, “A precast concrete tank fitted the design brief for this particular bio-pit construction. Cylindrical tank designs are not suitable as a constant below ground temperature is required to maintain the biological process and the aeration mats need to be fitted to a flat bottom structure. The main tank unit, together with the two weir walls and lid, were simply lifted into position, requiring little finishing works and minimising the amount of time our fitting team were below ground level. This precast concrete tank system is something we will certainly consider on future large vehicle washing projects.”
The tank was cast at FP McCann’s Byley precast facility in Cheshire.