$12m 'shaped and draped' landfill ready to open

With 120,000m³ of soil excavated and 30,000m² of liner laid, stage two of the Silverstream landfill is ready to open for business. 

The landfill is the region’s only designated Class A landfill, allowing it to take the widest range of waste material.

The landfill has been created by shaping the rock face into steps, putting porous concrete onto the face of the steps, then draping them with liner. The liner ensures all leachate will be captured and piped to the treatment plant in Seaview.

The gas generated by the landfill will be converted to electricity at the existing landfill gas power station. Hutt City Council’s general manager infrastructure Bruce Sherlock says building the gas extraction wells as the waste is placed rather than retro fitting means a more efficient capture. 

“We estimate we currently capture around 60% of the gas from the existing landfill and we expect this to be nearer 90% from the new landfill. The power station has the potential to generate up to 4 MW which is enough to power 8,000 homes. 

“We’ll transition to the new landfill over the next six months and work will continue to ‘shape and drape’ more of the landfill area at Silverstream. This means the landfill will meet the needs of Lower Hutt and Upper Hutt residents for the next 50 years.”

Council has spent $12 million on the work to date and the total cost of development over the life of the landfill will be approximately $34 million.