Dr Davies, 52, who joins from Royal Mail subsidiary Romec where he is managing director, will replace outgoing chief executive Paul Blackler.
Dr Davies has over 27 years’ experience in the industrial services sector, working in management positions at leading industrial groups such as Serco, Corus and Rugby Cement.
He is also a governing board member on the Technology Strategy Board, the UK’s national innovation agency which aims to accelerate economic growth by stimulating and supporting innovation.
Mr Blacker has stayed on as chief executive of Wetherby-based Augean during his notice period, but he will progressively step down from his role and will leave the group by the end of March.
Mr Blackler has now handed over all day-to-day control of commercial and operational matters to Richard Allen, who will assume the role of interim chief executive until Dr Davies joins the group in August.
Dr Davies’ current company Romec is 51 per cent owned by Royal Mail Group and the remaining 49 per cent is owned by Balfour Beatty Workplace.
Dr Davies also holds the dual role of managing director for Balfour Beatty Technical Services. The group said it has taken steps to strengthen its finance team during the interim period to ensure adequate resources are in place to enable Mr Allen to focus on his interim role.
Augean’s chairman Jim Meredith said: “The group carried out a rigorous selection process and Stewart stood out as the ideal candidate, both in terms of his track record and technical knowledge, to lead Augean during the next phase of the group’s development and beyond.
“Once again I would like to thank Paul for his contribution and wish him all the very best for the future.”
Dr Davies said: “I am very excited about this opportunity. It is clear that the management team has done a great job in putting in place a strong platform for growth, with a number of significant opportunities to build on, and I look forward to working with them to enhance Augean’s reputation as a leading hazardous waste business.”
Last month Augean warned 2012 results will be at the lower end of forecasts but said it expects to grow this year. The group said trading in the second half was “satisfactory”.