A Chara,
Your local authority Kerry CC, Dúchas (01-6473000), and the EPA (053-60600 - if the factory is breaching the terms of an IPC - intergrated pollution control licence), and the Central Fisheries Board (01-8379206) have roles to play in this problem. Maybe you could enlist the assistance of a local politician in spurring them into action. With elections in the air I'm sure they'd be more attentive than usual.
Bast of luck,
Brendan