The Old Whittington waste water treatment works, at Station Road, Chesterfield, is having a £27m investment to enhance the water quality of the River Rother and produce renewable energy.
This month old digesters at the site, which process waste and convert it into renewable material, should be replaced with new ones.
Project manager Georgia Wilson said: “The first of the new digesters should be operational this month, followed by the second one in September.
We anticipate that the energy generated from this process will enable us to generate at least 40 per cent of our energy onsite and helping us to keep costs down for our customers.”
The Yorkshire Water works treats the waste water from 100,000 residents across Chesterfield.
Its improvements will also help the site deal with predicted increases in population growth to 2025.
Engineering experts Earth Tech Morrison and Black and Veatch have been working on site since December 2010, and are due to complete it this autumn.
Helen Lally, project manager for the Freshwater Fish Directive scheme, said: “Once this project is finished, there will be lower levels of ammonia within the treated water, which should help to ensure improved water quality directly downstream of the works.
“We hope that this will encourage fish species such as salmon and trout, which haven’t been seen in some sections of the River Rother for over half a century, to return.”
Other features of the new works include a series of filters to remove debris, such as nappies, sanitary products and baby wipes from the waste water before it goes on to be treated.