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Client:
Regional Electricity Supply Company. (Name withheld for confidentiality)
Background:
Along with the rest of the UK electricity generation, distribution and supply industry the client has a large number of transformer sub-station sites which must be brought up to compliance standards. Even modest sized electricity transformers contain large quantities of oil for cooling and insulating. For many years there has been gradual leakage and occasional spills from routine re-filling and emptying so at most sites, without satsifactory containment, there has been a history of possible localised ground contamination and the risk of wider pollution in the event of major failure. All electricity companies have been aware of the problems of inadequate oil containment and have been making good, steady progress in upgrading their sites over the last ten years or so but this is a very costly exercise.
Brief:
The client had tried a variety of containment systems starting with the "belt and braces" approach of installing a concrete slab under the transformer and building a concrete catchment wall to form a "water-tight" secondary containment or "bund". Clear rules set down that this should be capable of retaining at least 110% of the oil storage capacity of the transformer. Traditional concrete construction is expensive, time consuming and the plant and machinery employed bring serious safety implications working on a live sub-station site. Creating a "water-tight" bund will also retain rain-water so an automatic pumping system is required which will remove any water build-up but safely retain any oil. Action:
P.P.L - Pollution Prevention were able to offer:-
- ReBund low-cost retrofit bund/secondary containment system
- BundGuard "YES to water - NO to oil" automatic pumping system Outcome:
ReBund is a sectional, panel based, retrofit bunding system which carries a minimum 10 year guarantee. The system can be installed on any site and can be configured to any size, shape or depth. When installed on a good, sound concrete slab it can be used on its own but in this case a heavy-duty "Sarnafil" liner was incorporated. Installed by a registered "Sarnafil" contractor the liner system also carries a 10 year guarantee. The full system costs a fraction of the price of traditional concrete construction and was constructed in a much shorter time thus minimising disruption and the risk of power outage. A pre-fabricated sump was provided in one corner of the bund and a P.P.L BundGuard unit installed to handle the water removal. BundGuard is a well tried and tested, low-cost, self-contained, intelligent and fully automatic pumping system which discriminates between oil and water. Thousands of these are in use throughout the UK and Europe and the system is recommended for this application in the latest DEFRA regulations. download an adobe PDF of case studies from this link |
Case Study 3
BundGuard - Automatic Separating Pump System