Fire-damaged material and concrete from inside the trickling filters at the Christchurch wastewater treatment plant should be completely removed by tomorrow.

The contractor, Southern Demolition and Salvage, is in the process of removing and transporting the final truck-loads of material to Kate Valley Landfill, which means this part of the project will be completed a month ahead of schedule.

Christchurch City Council Head of Three Waters Helen Beaumont said “the trickling filters were a key source of the odours during the warm, wet weather earlier this year, and having these structures cleared out is a key milestone in our recovery from the November fire.

We’re also very encouraged by the early biological progress we’re seeing in our new activated sludge treatment system.

Beaumont said “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 interim solution currently in place at the wastewater treatment plant has a design life of five years and is expected to be in place for two to five years, depending on the time taken to rebuild or replace the trickling filters.

Beaumont said staff were working on options now, with a decision expected by the end of the year.