The water which runs off the biomes is channelled into stylised concrete hoppers at the springing points of the biomes and eventually into two 120m3 underground sumps ready for filtration and treatment. A grit trap removes silt and grit and the water is disinfected by silver ionisation (whereby a low current is passed through a silver alloy electrode causing silver ions to be released and attach to and destroy bacteria present in the water). The treated rainwater is used for toilet flushing in staff and visitor facilities and as a humidification system.
The water is pumped to a pressure of 120 bar and dispersed via automated fogging nozzles in various parts of the Humid Tropics Biome which is kept at 90% humidity at night and 60% during opening hours. The picture on the right shows fogging nozzles hanging down from the inside of a biome roof.
We reduce our water usage in a variety of ways, ranging from taps that turn themselves off through to using harvested rain and ground water to irrigate our plants. About two-thirds of our water needs are provided from water we collect on site.
How we harvest water
Our underground drainage system collects all the water coming on to the site, which we use to irrigate our plants and flush our loos. We also harvest the rainwater that falls on the Biomes to irrigate the plants inside, top up the rainforest waterfall and maintain the high humidity inside.
How we reduce water use
To avoid using too much mains water at Eden, we:
use rain and ground water wherever possiblemonitor our water use via a meter, even on our watering hoseshave invested in the best water-efficient products we can, including low-flush toilets and taps which turn themselves off.
Why is saving water important?
Even though water doesn’t appear in short supply in the UK, using less mains water at Eden actually means we are:
Reducing energy use. The process of cleaning waste water at sewage plants is energy-intensive. All of it is cleaned to drinking standard, whereas a lot of it is just going down the toilet. Heating water – for example, for sinks – also requires lots of energy.Saving money. We pay for the mains water we use via a meter, and for any energy we use to heat it, so it is in our interest to keep this to a minimum.