Ironbridge acquired EnviroWaste from roading contractor Fulton Hogan in April 2007 for $365 million and went on to make 17 related "bolt-on" acquisitions.
Today, EnviroWaste and Australia's Transpacific form a duopoly in New Zealand waste management, with the latter the bigger competitor.
EnviroWaste's management team of Kim Ellis, Gary Saunders and Earl Gasparich will continue to lead the business under CKI's ownership.
Ellis, who headed up the NZX-listed Waste Management when it was bought by Transpacific in 2006, said CKI had paid a full price for EnviroWaste.
The $500 million price tag put on the company by Ironbridge was viewed with some scepticism when the asset was put up for sale last year.
"It's not like selling things in 2005 but I think under the circumstances it's a reasonable multiple and now we have moved on to a new owner," Ellis said. "From a management point of view, sure they made a few dollars - but not much - and it is now just business as usual under a new owner," he said.
Property development and contaminated site work - important sectors for waste management companies - have been slack over the last few years in the aftermath of the global financial crisis, but Ellis said the future was looking brighter thanks to better economic conditions.
EnviroWaste's earnings before interest and tax of $32.16 million in the year to June 30, 2012 was up from $25.45 million in the previous year. Revenue of $163 million was up from $144 million in the previous year. Finance costs took the bottom line to a loss of $18.98 million.
CKI is part of Li's Cheung Kong Group which includes, Hutchison Whampoa, and Power Assets Holdings.