Warrens Hill Landfill – Cell One Capping

At Council’s main landfill site at Warrens Hill, works are currently underway to remediate one of the solid waste disposal pits known as Cell One.   This pit has recently reached capacity and under Council’s license agreements, this cell is to be capped and made safe to minimise the likelihood of environmental harm.

As landfill cells reach capacity they are to be capped and contoured to minimise surface water impact and mitigate against the regionally high rainfall.   Environmental harm can and does occur when water interacts with buried waste and potentially generate damaging leachate.  This water can come from direct rainfall, runoff or the ground water table impacting the waste.

Generally, the water is prevented from contact with the waste by a combination of impermeable membranes and placement of clay material to isolate the waste.  Further surface profiling is used to minimise and redirect cross land water flow from the Cell.  Where required, pumps are used to maintain the separation of ground water from the waste.

Hinchinbrook Shire Council Mayor Ramon Jayo said capping a landfill is essential for environmental reasons.

“Sealing it means that there is no water penetration, if water were to get in, it rubs with the waste that's buried there, and then it creates the leachate,” he said.

“If that leachate escapes into the environment, it could cause environmental harm.

“Cell one at Warrens Hill Landfill and Resource Recovery Centre has been operating for at least 20 years, and now it has reached its capacity, so under the terms of our license condition, we had to undertake the relevant works.”

The Cell one capping experienced a failure and is currently undergoing remediation works.  The cap failure is the subject of litigation between Council and the designer of the cap.