De-Salination

Its own waste product, warm brine, discharges to establish a brine aerosol microclimate – the ideal conditions for the generation of salt marsh gardens, extending the nature reserve and preserving the timber structure of the power plant by keeping the wood perpetually moist. The same water source warms a public bath pool on the roof top via heat exchangers.

Like many urban centers with growing populations and water demand, Dublin’s water supply system is operating beyond capacity and lacks redundancy which often results in service disruptions. Predicted future increases in consumption mean this issue has to be addressed with new infrastructure.

Dublin’s water consumption is currently 540 ML/day while 1760 ML/day warmed salt water is released back to the sea from two power plants in Poolbeg, the South side of the bay area. A portion of this warmed water can be converted to potable water via low temperature thermal desalination: in depressurized containers the 10-20°C temperature difference between warmed and cold water bodies is used to vaporize saline water and condense potable water in a highly economical way with a positive environmental impact. At a low-conversion rate of 1%, the more saline water released back to sea can be diluted with low-tide river water and the water treatment work discharges, yet the system would provide water for 47,000 households / 122,000 people in a group water scheme.

The site for the building is on a floodplain therefore all services are elevated on a timber trestle structure. The building is vertically split into 3 levels: on the top floor, using heat exchangers, the same heat source warms water for public bathing; on the first floor changing rooms with showers are mixed between desalination machinery; at ground level, in the web of structure, walkways are placed.

The waste product of the desalination process, brine, is discharged off the top of the structure to set up an environment of salt water aerosol. Water washing down the side of the structure transforms the surrounding landfill into a landscape of salt marsh garden which extends the habitat of the nature reserve of the area. In close proximity to the structure a New Zealand species of mangroves are planted, while further away from the structure, as the environment cools, native species are planted.

Durability of the timber structure is ensured by the preservative environment of brine wash and aerosol, and the selection of locally available water tolerant species: alder, larch, elm and Douglas fir. Redundancy in the buildup is introduced with biodiversity in the bracing, the use of varied sets of species, to schedule maintenance. This build-up is expected to last, based on self-preserving salt graduation tower precedents; well-over 100 years, highlighting the effectiveness of building with timber in salty and wet environments.