Filtration system for the Eden Project removes contamination caused by organic matter and debris from the water course in the rainforest display area of the largest conservatory in the world
Purite, a UK manufacturers of water purification equipment, has developed a filtration system for the Eden Project to allow the organisation to remove contamination caused by organic matter and debris from the water course in its rainforest display.
The Purite system is minimising water usage in the display as well as guaranteeing the purity of the water, for both aesthetic reasons and to meet public health and safety requirements.
Located in Cornwall, the Eden Project opened in March 2001 and has since become one of the UK's leading visitor attractions, with 1.2 million visitors in 2004.
One of the main areas of the Eden Project is the Humid Tropics Biome, which is the largest conservatory in the world, measuring 240m long, 110m wide, and 50m high; it contains over 1000 plant species and a variety of birds, lizards and frogs.
Within the Humid Tropics Biome is the rainforest display, featuring the trees and plants of the world's tropical regions and includes a man-made watercourse, with a 10m high waterfall, splash pool, cascading stream and lagoon.
The Eden Project worked with Purite to develop a system to ensure that organic matter and debris was removed from the watercourse, while allowing as much of the water as possible to be recycled for other purposes.
This watercourse is fed by pumps that are located in a pumping station adjacent to the lagoon, from where the water is drawn.
A 65m long stream runs between the splash pool and the lagoon.
The entire area through which the stream runs is maintained at a temperature in excess of 22C with a relative humidity of 90%.
Adjacent to and throughout the length of the stream is jungle.
Consequently, a combination of leaves, organic debris, soil and fertiliser continuously runs or falls into the stream.
Although this forms an integral part of maintaining the ecology of the jungle feature, it creates a few negative effects, as Colin Longair, system engineer for the Eden Project explains: "When the organic materials combine with the stream at such high temperatures they effectively create a living soup.
"For visitors to this particular exhibit, part of the attraction is experiencing the vapours, sprays and splashes created by the feature, so we need to ensure that water is kept as clean as possible.
"In addition, with such high levels of water vapour in the air, it is important to maintain water purity to eliminate the risk of airborne contamination".
The primary filtration solution Purite developed for the Eden Project combines a specially designed multi-media unit using standard potable water components.
The system incorporates separate inputs for service and backwashing as well as individual drains to split and reuse the rinse waters.
This was achieved by using site collected rain water for the filter backwashing, and by diverting the heavier soiled backwash water to special composting soak away drains.
In addition, the rain water used for the rinses is not wasted, but separated and returned to the closed system to make up the backwash losses.
The system has a capacity of 13m3/hr and can remove particulates down to five microns in size.
In addition, the system can automatically adjust itself to meet changes in seasonal organic loadings.
Colin Longair concludes: "Our ethos at the Eden Project is to be as environmentally aware as possible and this was the major factor in selecting Purite.
"The system it has developed for us meets all the requirements in terms of ease of operation, performance and reliability, is simple to operate, energy efficient and does not require any chemicals or consumables".
