Water companies can release untreated sewage when it rains heavily to stop homes being flooded.
However, without full treatment, sewage can cause more damage to the environment and swimmers.
Chris Borradaile, county business leader for wastewater in Greater Manchester at United Utilities, said the work on Sheepfoot Lane was “an important scheme that will help to improve the water quality in Plumpton Clough and the River Irk”.
“We are playing our part to improve the health of the region’s rivers and delivering the step change that customers and stakeholders want to see.”
United Utilities says it is working with Oldham Council, Transport for Greater Manchester and the football club to minimise disruption.
