Pollution Of The River Irk

I wonder how many years it will take for the River Irk to recover from this!!

The source of the pollution leak has been traced back to the retaining bankside wall of a detergent factory in Middleton. The EA are unable to ascertain if its detergent or bleach which has entered the water course until the foam is slowly washed away through natural causes
It has taken years for the River Irk to get to a state where it could support a decent amount of aquatic life, destroyed in minutes by morons. This foaming of the river has taken place many times during the last 20 years, but hasnt been this bad for a long time. One stupid Plc ruining a river valley. I'm not going to type anymore today because i just can't.