Laura Hepburn and Jonathan Guy Brudenell are to answer 14 separate charges at Teesside Crown Court in relation to Greenology Ltd in Redcar, where the fire began in April 2020.
The fire was widely reported at the time as smoke could be seen from as far away as Whitby.
Yet an Environment Agency investigation afterwards uncovered evidence of malpractice by the directors of the firm which manages it, Selective Environmental Solutions.
One of the accused, Peter Waldron on Hinton in Northallerton, has already admitted breaching the terms of an environmental permit but Hepburn, who is from Robin Hood's Bay, and Brudenell both denied the offences against them.
Brudenell, from Sandsend, is accused of three offences connected to the use of environmental permits during 2018 and 2019, and one charge of keeping controlled waste likely to contribute to pollution or harm human health in 2019. He is also charged with taking part in the management of a company while under bankruptcy restrictions.
Hepburn is accused of two charges of breaching environmental permits and two of keeping controlled waste likely to contribute to pollution or harm human health in 2019 and 2020.
Greenology and Selective Environmental Solutions also face charges over alleged permit breaches.
A preliminary trial date was set at Teesside Crown Court of February 6, 2022, by Judge Jonathan Carroll which could last up to ten days.
But Lee Fish, prosecuting on behalf of the Environment Agency, said there had been preliminary discussions and it was the “collective view of the parties that this is a case capable of resolution”.
It was agreed a further hearing would take place on March 4, allowing further legal discussions to take place in the meantime.
The fire was originally investigated as arson but no charges were ever brought in relation to this.
Hepburn, also from Sandsend, promised that the plant would resume operations as soon as possible to protect jobs and committed to rebuilding the site.
She established the business herself and was later included in the 2020 Northern Power Women List.
Her vision for her green business has seen tonnes of material recycled, preventing it from being taken to landfill sites or incinerated.
The mother of three originally trained in design and worked in the TV and film industry on productions including Game of Thrones and Gentleman Jack before changing careers to waste management.
Educated at York College and Teesside University, she studied for a Masters degree in innovation and sustainability at the University of Oxford and was a visiting lecturer there for seven years.