Reed-bed system ‘may defeat’ toxic algae on Killarney lake
The solution to annual outbreaks of toxic algae on Killarney, Co Kerry’s biggest and most famous tourist lake, may be a simple reed-bed system.
Questions are being raised about the treatment plant in the Kerry tourist haven as algal blooms this year are emerging in Lough Leane despite a major 15-year programme lowering phosphates.
The Lakes of Killarney are at their lowest level in living memory. Anglers from Cork and Kerry, members of the Trout Anglers’ Federation of Ireland, were the ones to bring attention to the emergence of blue-cyanobacteria, or blue-green algae, in a number of places last week and the ‘pea-green soup’ that indicates its presence.
The council has erected signs warning dog owners particularly not to allow pets to enter the water. In 2016, a number of dogs died from toxic algae on the Killarney shoreline.
In 1999, a major catchment study got underway and the likely culprits were identified as agriculture, forestry, inefficient septic tanks, but also the local authority and the phosphate reduction targets that had been set.
Water quality on the major conduit of pollution, the Flesk River, has greatly improved, however.
However, concerns remain about the town’s sewage treatment plant alongside Lough Leane and whether it has the capacity to deal adequately with the continuing growth in the town’s population and tourist numbers.
About 1.5 million tourist beds are sold each year in Killarney which now has a resident population of around 15,000, with a greater area population of around 30,000.
Independent County councillor Donal Grady had warned two months ago that the plant was overwhelmed in flood conditions and believed, with the exception of anglers, the lake did not have sufficient “watchdogs”.
Fellow Independent councillor Michael Gleeson is convinced the solution lies in addressing issues with the Folly Stream, the outflow from the sewage plant directly into the lake.
He said grey water from the stream was used during this dry summer for the watering of municipal gardens and roundabout plantations.
Be careful down by the lake… The algae is back... pic.twitter.com/JSCf7IndPb
— Killarney Advertiser (@KAdvertiser) July 29, 2018
The final report of the study into Lough Leane pollution, published in 2003, pointed the finger at the Folly.
Due to misconnections from the plant and overflows, the stream had high levels of nutrients which was going directly into “the shallow waters of Ross Bay”, it found.
The stream remains an issue and last year monitoring by Kerry County Council and the EPA found it had been enriched with bacteria.
Mr Gleeson said he has been concerned all summer and was glad the lake had lasted so long without an outbreak.
The solution is a reed-bed system, he said, to treat the Folly stream and plans to lead a campaign to have a partially-built reed bed revived.
The reed-bed will allow the water to be reused, perhaps, and reusing water was “an international reality”, he said.
The bed is on the side of the lake is where there is most evidence of pollution.
“Any threat direct from the Folly stream would be removed,” Mr Gleeson said.
Irish Water, meanwhile, said the Killarney Wastewater Treatment Plant has a capacity for a population of 54,000 and it was operating within its capacity and in full compliance with its wastewater discharge licence and environmental regulations.
