Northern Ireland

From flush to freshwater - NI's latest green eco loo

Wetland at Castle Archdale caravan park
Image caption The new green loo at Castle Archdale caravan park is just the second in NI

From flush to freshwater, Castle Archdale caravan park in County Fermanagh is setting new standards.

The Environment Agency has leased land to NI Water for an integrated constructed wetland.

This is a fancy way of saying there are lots of plants and wildlife hard at work.

"This is a process for treating wastewater," said Dermott McCurdy from NI Water.

Image caption Biological processes are at work

"After you flush the loo in the caravan park, the wastewater makes its way to the inlet.

"There are two settlement ponds and that takes out about 30%, which settles to the bottom as sludge.

"It then flows into three ponds, which are only around 100mm (4in) depth."

It may sound shallow, but that amount of water is all it takes.

"In that depth of water, various things happen," Mr McCurdy explained.

"First of all, there are bacteria in there and they eat the wastewater.

"The root mass within the plants absorbs the nutrients and the metals and things like that if there are any, and there are very few metals from Castle Archdale."

Image caption A walk in the park?

He went on: "Then the ultraviolet light from the sun acts as well to kill off bacteria that you don't really want returning to the environment through the watercourse at the end.

"And by natural, biological processes of the plants and the sun and the action in the ground, the wastewater comes in one end, gets treated and goes out the other end, cleansed, back into the environment."

'Grow naturally'

The five ponds can easily deal with the waste produced at the caravan park, whether it's during the summer when 600 people are staying or as few as 50 in the winter.

"This place actually copes much better than a traditional plant because the plants will grow naturally with rainwater," said Mr McCurdy.

"Whereas, with a traditional works, it would have difficulty ramping down for the small populations in the winter."

There is next to no smell at the site, which is open to the public as a walking path.

"This is an ecosystem which is man made," said Mr McCurdy.

"People can come here, walk their dog, go round the park.

"They will see different dragonflies and things like that, if they take their time and be quiet.

"They might see ducks which have nests on the ponds and will fly up in front of them."

'Big concrete'

There is also very little noise, apart from birdsong.

Unlike a traditional plant, virtually no electricity is needed to run this wetland. What little is needed, for monitoring flows, is provided by a bank of just six solar panels.

This is the second plant of its type that NI Water has built and it will not be the last.

"We have three planned as experimental sites, to prove that the process works," said Mr McCurdy.

"We've finished one at Stoneyford, outside Lisburn, we're here now in Castle Archdale and we're going to build one in Ballykelly."

While acquiring land on a scale to serve a much bigger population than the caravan park might be difficult in built-up areas, Mr McCurdy is firmly of the belief that the wetland approach is worth taking where possible.

"It's a nice place to come and walk around which actually adds to the local environment, as opposed to big concrete structures which would take away from the environment."

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