Wanganui District Council is making progress in its attempt to fix its wastewater treatment plant and tackle the foul smell that has afflicted parts of the city since before Christmas.
The council says the smell is partly caused by the failure of the wastewater system to cope with sludgy discharges from local factories.
Infrastructure manager Mark Hughes says new high-tech equipment was dropped by crane into the top pond and will be trialled on Tuesday.
It is hoped the new aerators will stop the sludge from the bottom of the pond being pulled back to the surface.
Direct treatment of the sludge is also going well, with good bugs being injected into the pond to reduce the level of sludge, the council says.