Pham Cao Thang, deputy general director of Hanoi Urban Environment Company (Urenco), which operates the landfill, said the volume of leachate in waste stabilization ponds in the landfill in Soc Son District has exceeded permitted limits.
Over the past few days, due to heavy downpours, wastewater has leaked into containment walls, which are in danger of collapsing, the local media reported.
The reopening will be decided by the Hanoi Department of Construction, Thang added.
After the temporary closure of the Nam Son landfill site, over 4,600 tons of waste will be transported to the Xuan Son waste treatment facility and Thien Y and Thanh Cong waste-to-energy plants each day.
In early October, the Xuan Son waste treatment facility in Son Tay Town, Hanoi City's second largest landfill, temporarily stopped receiving waste for 10 days due to a failure of leachate reservoirs.
The city discharges some 5,000 tons of household waste each day, with over 4,000 tons transported to the Nam Son landfill site to be buried. The remainder is treated at the Xuan Son waste treatment facility using the burial and incineration methods.