Lincolnshire-based HL Foods faulty anaerobic digester produced rotten cabbage-like smells and egg smells which affected neighbours in the surrounding area.
HL Foods site owner Richard Sloan told EA investigation officers that waste water from the vegetable preparation process was diverted to aerators [a device that mixes air with substance] past the anaerobic digester when it was faulty and there had been problems getting the biomass needed to get it working again properly.
The firm tried some measures to take pressure off the waste water plant but admitted they had not reduced production in October because they were trying to balance the system.
EA officer Richard Freestone detected egg smells when he visited the site, which was strong towards the fan section of the plant.
Prosecutor Mark Watson told the court about the effect of the smells on neighbours. One householder had to cancel some visits from friends because of strong smells, had lost his appetite many times and had trouble sleeping. He described it as a rotten vegetation smell and almost like a dead rat type smell".
Watson said the failure of HL Foods to fix the anaerobic digester resulting in smells generated could be considered intentional or reckless.
Freestone said: It is disappointing that we have had to resort to prosecution to get this company to up their game and take full responsibility for the impacts of their operation on the local community. Operators need to understand that where persuasion and influence fail, we will take formal action.