Christchurch City Council says the work should be finished today.
The contractor, Southern Demolition and Salvage, is removing and transporting truck-loads of the material to the Kate Valley landfill in North Canterbury.
Council head of three waters Helen Beaumont said she was delighted at how quickly the contractors have been able to complete the work.
"The trickling filters were a key source of the odours during the warm, wet weather earlier this year," said Beaumont, "and having these structures cleared out is a key milestone in our recovery from the November fire."
She said they were also encouraged by the early biological progress they were seeing in the new activated sludge treatment system.
"The oxidation ponds have been the main cause of the odours, but as the better-quality wastewater works its way through the ponds over the coming weeks, we'll see their health progressively improve.
"The odour levels will significantly drop as a result."
The council said the interim solution currently in place had a design life of five years, and was expected to be in place for two to five years, depending on how long it took to rebuild or replace the trickling filters.
