A Ballybofey soft-drinks manufacturer was fined €1,250 plus €2,500 costs after pleading guilty to a number of charges under the water pollution act.
Mulrines were sued by Donegal County Council at yesterday's sitting of Letterkenny District Court for discharging up to eight times the amount permitted under their waste licence on five separate occasions in 2009.
Almost a further 40 charges against the company were struck out following an agreement reached with the council's solicitor, Mr Paddy McMullin.
The charges related to illegal discharges from Mulrines factory in to the nearby salmon rich River Finn as well as the local public sewer network.
The court heard that the discharges in to the sewer led to the failure of the council's sewage treatment plant in Stranorlar.
The Councils solicitor Paddy McMullin said the problems with the treatment plant led to the council themselves being prosecuted for polluting the Finn as well as a large number of complaints from the public about bad smells.
The council's Executive Scientist, Dr Joe Ferry, said management at Mulrines told them that the problems were due to operational failures.
Dr Ferry also told the court that Mulrine had spent up to €250,000 on, machinery to treat the effluent before it left their plant, however, it was not always maintained or switched on.
He admitted, however, that the current Operations Manager at the plant had succeeded in 'steadying the ship'.
Defending solicitor, Mr Niall Sheridan, argued that a number of the offences were as a result of human error and power failures in the middle of the night.
Judge Seamus Hughes said he understood that it was difficult for family run companies to comply 'overnight' with EU standards and practices in the current economic climate.
He convicted and fined the company €250 for each of the five charges and ordered Mulrine to pay the council's costs of €2,500.