Geosynthetic Solutions for Browns Plains Waste Facility

Project background

Browns Plains Waste and Recycling Facility is one the largest and most modern waste facilities in QLD.

The facility is dedicated to recycling as much waste as possible while also ensuring the health and safety of local residents. Because of this, the facility’s management team like to plan ahead and maintain a smooth operation, which includes managing potential pollution streams before they become an issue.

Problem

Like many waste facilities, the Browns Plains site is divided into cells in varying stages of completion.

The phase 2 section of Cell 5E is located in a low-lying area and surrounded by existing cells that have already been completed. This means that Cell 5E was experiencing the typical leachate issues of waste facilities, and also surface water runoff from the higher neighbouring cells.

Solution

After reviewing the various geosynthetic solutions available and carrying out risk assessments, a system was designed using three different geosynthetics.

A 300mm compacted clay layer with Coated GCL Bentofix® NSP4900 X5F geosynthetic clay liner provided a long term seal. This Bentofix product is a needle punched GCL with a 500g/m2 textured polyethylene coating applied to its upper surface. The coating provides additional strength and durability against chemicals and potential desiccation, Ion exchange, piping and moisture lost to the GCL. It also improves the hydraulic performance of the lining system by 1000 times compared to a similar GCL without the polyethylene coating, and 100,000 times compared to a compacted clay liner.

Then, a layer of Profab® Ultra AS1000X polypropylene (PP) geotextile provided a separation substrate before the placement of drainage aggregate.

Finally, ACEgrid® reinforcement geogrid was used as veneer reinforcement on the side slopes to provide extra stabilisation properties to the structure, particularly while placing the waste against the walls.

This multilayered system enabled the local city council to keep costs of construction to a minimum while providing an environmentally safe landfill cell.

During construction, a sudden storm came through the area dropping 40mm of rain in the space of 45 minutes. The GCL was still exposed and mid-installation during this period. After site inspection and random sampling, no damage or excess hydration was done to the GCL or the compacted clay below, which was mainly because of the extra polyethylene coating on the GCL.

Results

The system of a coated GCL, PP geotextile and geogrid has enabled a fast, safe and cost-effective construction of a new cell for the local area, at the same time reducing the site’s carbon footprint.

It has also ensured that any surface runoff which could be carrying toxic leachate will be trapped and disposed of safely, ensuring no harm is done to the environment and the locals.

This system has been so successful it has become widely adopted by professionals all over Australia to manage waste leachate and runoff. For further information please contact National Product Manager Andy Warwick - andy@globalsynthetics.com.au.