The decision to hold the hearing outside the affected district had been criticised but hearing chair Brent Cowie said that was unfair. Manfeild was appropriate given its location between Palmerston North where Midwest and council officers are based, and submitters, he said.
The commissioners visited the landfill on Monday ahead of the nine-day hearing and said they would visit properties of affected submitters if requested.
The opening days will run through large amounts of technical information before submitters begin presenting, probably on Thursday afternoon.
Midwest Disposals general manager Paul Mullinger said the hearing was the culmination of seven years' preparation. "Now's my hour," he said.
Mr Mullinger ran through the history of the company and its extension goals.
"This application builds on the infrastructure that's already there," he said.
There had been criticism Bonny Glen was looking to double or triple its intake over night, he said. "That's not the case. We've taken the worst-case scenario. We've made this application far enough in advance so that we get a seamless transition."
He said the application also included options to add greenwaste facilities.
"We also accept that there'll be far more stringent consent condition that are applied."
Mr Mullinger also addressed the opposition to the leachate produced by the landfill. The leachate is currently trucked from the dump to RDC's waste water treatment plant under an informal agreement. The negative impact it was having on the plant was top of the list of concerns from submitters but deemed outside the scope of the hearing. While a promise had been made to sign a formal agreement, Mr Mullinger said the company was also looking at other options.
"We are also fully aware if there needed to be an upgrade at that plant, we would be asked to contribute to that," he said. "We're also looking at opportunities to do it on our own. There are technologies to do that. It's not just something that we've said it's not our problem, lets put it on Marton."
Earlier, Midwest's lawyer Jan Caunter argued the importance of having a landfill in the region.
"There is a continued need for a regional landfill facility, with associated minor environmental effects ... those factors must be considered alongside the social and cultural needs of those submitters who have opposed the application."
