Central Otago District Council

Roxburgh Wastewater Treatment Plant Desludging

CODC requires an experienced contractor to desludge two oxidation ponds at the Roxburgh Wastewater Treatment Plant (WWTP).
This procurement relates to the desludging and dewatering component only.
Disposal options will be contracted out on a separate contract at the end of the drying period.
The WWTP treats municipal wastewater from the township of Roxburgh via (recently installed) screens and oxidation ponds, with disposal to land via infiltration swales.
The two oxidation ponds are in series, separated by a narrow earth embankment and connected through a pipe and valve system.
The ponds have a concrete waveband while the base is constructed of compacted earth and selected silts which act as a low permeability liner.
Effluent from the oxidation ponds is piped to five basins which allow wastewater to infiltrate into the ground.
A sludge survey was carried out by Conhur in 2022. The sludge amount has not changed significantly since the sludge survey was carried out.

Department/Business Unit: Central Otago District Council