Tank within tank challenge complete as FLI CAP Technology brings winning aeration system to leading food producer
Written by: Chris French
Fifteen years on from its first wastewater project with one of the UK's most popular providers of freshly prepared food, FLI CAP Technology has completed its latest bespoke installation for the much-loved brand.
To meet the ever-increasing demand for the food producer’s products, FLI Cap Technology were tasked partly with providing a new CIRIA-compliant (Construction Industry Research and Information Association) above-ground treatment tank that would ensure safe secondary containment of hazardous liquids. Creating a second-skin tank around the outside of a vessel presents access challenges as FLI CAP Technology's Divisional Director Chris Woods, explains.
“The best solution for aerating our customer’s tank,” he said, “was with submersible mixers, but we were keen to avoid the health and safety issues involved with working at height when removing the equipment for maintenance.
“Based on its quality, efficiency and longevity we specified Landia's AirJet system which includes their proven chopper pump. We were able to install this 11kW system at ground level for the required tank-within-tank concept, with Landia assisting us in creating an elevated aspiration system so that the Venturi nozzles would create sufficient mixing for the glass-lined steel tank (inner diameter 6m, height 9.4m; with an outer bund of 7.9m diameter and a height of 7.9m)”.
A simple aeration system that can be easily installed in most tank types, often without emptying the vessel first, Landia AirJet is an ejector aerator, typically used for the aeration of wastewater or sludge, comprehensively mixing and aerating the whole tank to eliminate unpleasant odours. AirJet is also suitable for supplementary aeration at peak loads, and in connection with cleaning or flushing of equalization tanks.
Chris Woods added: “As our customer expanded to create a fourth production line for a 35% increase in capacity, we needed to find an innovative design that greatly reduces residual risks with the project. Ensuring that our customer met CIRIA’s important C736 requirement was paramount, but keeping moving parts at ground level also makes maintenance significantly easier for them, greatly reducing health & safety issues, hassle, and costs”.
In addition to the bunded balance tank and aeration system, FLI CAP Technology’s complete turnkey effluent treatment solution featured a solid screen and a primary treatment system comprising of chemical dosing and dissolved air flotation (DAF).
FLI CAP Technology had first carried out an extensive survey of the existing effluent treatment plant to assess condition, capacity and environmental compliance required to meet future needs. To ensure that the food manufacturing plant could consistently discharge treated effluent in compliance with the local water company’s consent parameters, the report identified that a replacement treatment plant was needed. However, no additional site space was available.
This led to FLI CAP Technology developing a detailed plan to install the new effluent treatment solution in a phased approach, in order to minimise disruption to site and maintain the facility’s operation. The 18-month project included all aspects of the design, scope of supply, M&E installation and commissioning.
Phase One saw the breaking out of the existing block chemical store and installation of new final effluent discharge sewer, plus a new ETP (Effluent Treatment Plant) building, and Dissolved Air Filtration (DAF) equipment (to be fed by the existing screen and balance tank).
During Phase Two, the existing DAF system and ETP building were removed while civil construction of new plinths for the new screen and new balance tank took place (where the now old ETP building was located).
In the third and final phase, the old balance tank and old screen gantry were removed, as were old submersible pumps, whilst new raw effluent suction pumps were installed.
The new effluent treatment plant is fully automatic; controlled by a new PLC control system with colour touchscreen. Treated effluent is returned to the sewer connection via a monitoring station.
FLI CAP Technology’s Chris Woods, continued: “This was our seventh project and perhaps the most challenging yet for this very important customer. Although their business has grown significantly during the past decade and a half, we’ve proved that we can continue to meet all their effluent treatment plant needs.
“We’re seeing more and more requirements for secondary CIRIA-compliant containment. By working with Landia we have, when required, the flexibility to introduce top quality ground-mounted pumps/mixers through the tank voids as part of our overall solution. The team at Landia are always quick to respond to our needs, and we always have total confidence in their equipment”.