The Ducos Landfill is located approximately five kilometres north of the central business district of Noumea and is in a predominantly industrial area. It services the entire city of Noumea and surrounding districts, accepting a variety of waste including putrescible, sewerage, oils, building demolition, tyres and other industrial wastes from the country’s mines. Anecdotal information indicated that the site operated as a Landfill since 1963 and was originally constructed on reclaimed Land.
The main landfill pond was considered geotechnically weak due to fracturing of the pond wall. This fracturing meant that, if the wall ruptured following high rainfall events, the entire 25,000 m³ volume of waste sludge was at risk at discharging into the adjacent bay, and subsequently the Pacific Ocean.
The site required stabilisation of existing leachate pond infrastructure, de-sludging of leachate ponds, improved leachate collection capabilities, improved storm water management, and immobilisation by microencapsulation to stabilise the sludge and sediment for use as landfill capping.