The project is due to get underway on the first of five sites next month and will see up to £18m spent on a new pumping station and sewer.
The work will bring the north and south beaches in line with much stricter water quality standards.
The sewer, which will be laid 10m underground and run for 800m from Springfield Avenue to the new pumping station, will carry storm water which currently spills into the Gypsey Race.
A new sea outfall expected to cost up to £16m will ensure that the storm water is transferred 2km out to sea.
Duncan Warner, project manager, said: “We’re committed to doing all we can to improve our sewerage network and play our part in helping to further improve beaches and bathing waters along the Yorkshire coast, with the aim of the region boasting some of the best beaches in Europe.”