The program of improvements is expected to be completed in November 2012 with the newly-extended treatment works being fully commissioned in December 2012.
Northern Ireland Regional Development Minister Danny Kennedy said the upgrade project is an important program of work involving significant financial investment by NI Water.
"I welcome the news that elements of the upgrade have now been completed and ongoing work is on schedule," Kennedy said.
NI Water Wastewater Capital Procurement head Dermott McCurdy said the local stakeholders that central to the £4.8m project was the construction of two large primary settlement tanks which would substantially increase the capability of the treatment works and enable it to deal more effectively with any unexpected discharges to the sewerage network.
"The large primary tanks already under construction will substantially increase the treatment capacity at the works," said McCurdy
"The refurbished and extended odour control process will further serve to alleviate odour problems in the future."
