It is the second time the AD plant has leaked since it was built two years ago.
Last year thousands of litres of waste flooded nearby farmland when a tank ruptured.
The Environment Agency is looking into the incident at the university today (Friday). It is not yet clear how much waste has leaked out.
Vice-chancellor at Harper Adams, Dr David Llewellyn, said: “We were made aware of an incident with one of the processing tanks on the anaerobic digestion plant early this morning.
“The relevant authorities have been informed. Our priority at this stage is to make sure the site is safe and to assess what exactly happened and what damage has occurred. We will be taking all possible steps to minimise any impact on the surrounding environment.”
The plant, which was opened in January 2012, operates on food waste and slurry.
It was built to demonstrate how farmers and businesses can diversify using waste products to generate power and an additional source of income.
The facility was developed through a partnership between Harper Adams, Biogen Greenfinch and E.ON.