Irish Water admitted eight counts of breaching the terms of its licence in connection with levels of ammonia and orthophosphate from a wastewater treatment plant in Boherbue, Co Cork.
The existing plant discharges into the Brogeen river, a protected conservation area and home to the freshwater pearl mussel.
The court heard the level of ammonia discharged into the river was not supposed to exceed 0.5mg per litre, as stated in the plant’s licence, but it has been seven times that over the last four years.
The court heard five times the set limit of orthophosphate discharged into the river.
EPA file on this Irish Water plant is here: