Bio-filter system clearly better
Bio-filter system clearly better
AN experimental bio-filtration system on a Gwynedd farm is removing up to 95% of the pollutants in dirty yard run-off water.
Provisional results are so good that Glyn Robertss landlord, the National Trust, might install similar arrangements on many of the 51 farms that make up its 8209ha (21,316 acre) Ysbyty Estate.
The demonstration project was established after the Trust ran a pollution potential audit on all its tenanted units. This revealed that while slurry storage at Dylasau Farm, Ysbyty Ifan, was adequate in a normal year, it could overflow during a very wet winter. There was a risk that contaminated run-off could reach the nearby River Conwy.
Rather than erect a bigger slurry lagoon, or new dirty water store, new guttering was put on buildings to remove clean water, and new drains were put in to divert soiled yard water to a settling pond. As the level in this rises, partly decontaminated water exits through a sluice and via perforated drainage pipes to a series of interlocking stone-filled trenches sunk like terraces into two sloping areas with little agricultural value.
Dirty water weeps out of the perforated pipes, through gravel and into soil making up the banks of the ditches, on which willows and poplars have been planted for their roots to take up suspended nutrients. The trees will be planted on a rolling rotation and harvested after seven years to fuel a central heating boiler in the farmhouse.
When water drains from terraced areas it will pass through yet to be planted reed beds for final decontamination. Even without the reeds, and with very immature trees, monitoring by Cardiff University indicates that between 80 and 95% of pollutants are being removed.
"Before the filtration system was put in I was constantly worried about the slurry store overflowing," Mr Roberts told Welsh Rural Affairs Minister Carwyn Jones when he visited the beef and sheep unit to meet Farmers Union of Wales members.
"This combined cleaning and biomass production system is the sort of sustainable farming politicians want and should be grant aided."
The project cost about £12,000 to set up and was grant aided through the Leader Scheme and by the National Trust. *
From settling pond to clean water. Glyn Roberts believes the bio-filtration system at Dylsau Farm will be a success.
FILTRATION SYSTEM
• System cost £12,000.
• Cleans dirty water.
• Biomass production too.