Installing separate potable and non-potable water supply systems at Heathrow Terminal 5 has achieved a 70% reduction in potable water consumption system resulting in financial and environmental benefits.
Potable water is now used for activities such as catering and showers with non-potable water being used for toilet flushing, vehicle washing and fire-fighting on aircraft stands.
The non-potable water is sourced from goundwater abstraction, rainwater harvesting and recycled water. Requiring minimum treatment prior to use, this has proved extremely sustainable in terms of cost, energy use and resource efficiency, when compared to potable sources. Although the construction costs of a separate potable and non-potable system exceed that of a single potable system, the operational cost is approximately halved, meaning the dual system pays for itself in a little over two years and makes a substantial saving over the design life of the project.
Case study provided by BAA