A five month process of desludging Roxburgh's wastewater ponds is complete, creating a temporary pyramid of geo bags for drying.

SiteCare completed the project using a dredge at the two wastewater ponds on behalf of the Central Otago District Council (CODC).

Sludge extracted was pumped into geo bags and now, with the project complete, a pyramid of the bags will be left on site for about 12 months, or until they achieve the necessary level of dry solids.

Once ready, they will be disposed of.

The process of desludging was an important maintenance activity for waste stabilisation ponds because sludge accumulation reduces treatment capacity and can result in an increase in odour transmissions.

CODC project support infrastructure Laura McLellan said there was no specific frequency for the process to take place.

Geo bags full of sludge taken from Roxburgh's wastewater ponds. PHOTO: Supplied

“This varies based on factors such as population, size of pond, survey report information and behaviour of what people are flushing.”

She said the community could help reduce the amount of sludge that accumulates by ensuring they only flush the three Ps: pee, poo and paper.

“This practice minimises both the quality and quantity of sludge in the ponds. After all, the less that goes in, the less that needs to come out, right?”

Laura said although the community would not notice a day-to-day difference now that the work is complete, it was essential to recognise that effective treatment would positively impact overall operational performance.

“Without this effort, the consequences could have been significant.”

Last year, a screen was also installed at the inlet pipe of the Roxburgh wastewater treatment plant to help filter out objects such as rags, plastics and any other foreign matter that isn’t in the wastewater.

“Despite this improvement, it remains crucial for the community to continue adhering to the three Ps rule.”