Burwood Resource Recovery Park (BRRP) is a state-of-the art construction and demolition waste processing plant. It was established following the Christchurch earthquakes to manage the receipt and resource recovery of earthquake waste.
BRRP is a subsidiary of Transwaste Canterbury Limited, a joint venture between Waste Management NZ Ltd, Christchurch City Council and Waimakariri, Selwyn, Ashburton and Hurunui District Councils.
The project has received funding from the Waste Minimisation Fund, which is administered by the Ministry for the Environment.
When Christchurch was hit by a second major earthquake on 22 February 2011, much of the CBD was destroyed and large parts of the eastern suburbs. As a result, the city may face demolition of approximately 1,000 CBD buildings, up to 500 commercial building outside the CBD and perhaps upwards of 10,000 residential houses.
A large proportion of the mixed material from the deconstruction and reconstruction of these buildings has been, and continues to be deposited at BRRP for processing and recovery. It is expected the site will receive a minimum of 500,000 tonnes of earthquake waste material, and potentially up to 750,000 tonnes.
Most heavy waste arising from the demolition of buildings, such as clean concrete and brick is taken to Lyttelton Port reclamation site or other cleanfill sites.
This leaves the essentially lighter structural material, cladding and decorative contents of empty buildings to be sorted at Burwood.
This type of mixed material is typically low quality in recycling terms i.e. low sale value potential and high difficulty to process.
As a result, the material requires a very sophisticated sorting process to recover the maximum amount of reusable product.
Trucks carrying earthquake waste are weighed when they enter the Burwood site, and the documents relating to the nature of the material and origin are checked.
Each truck is then directed to the remote stockpile area at which point they have a visual inspection to ensure it contains material that is accepted at the site. This is undertaken by a ‘Spotter’ standing on an elevated tower. The ‘Spotter’ then directs the truck to tip at a specific location within the stockpile zone.
The stockpiling of the material is performed with care, to preserve the recovery potential. A bulk pre-sort occurs during tipping at which time excavators pull out any bulk metals and other large objects before carefully placing the balance into a stockpile that is up to 20 metres high and that covers an area of 6.5 hectares.
This process operates 12 hours a day, six days per week.
BRRP has a three stage sorting process for mixed earthquake waste material.
Stage 1 - Heavy pre-sort of material as it arrives at the stockpile site
Stage 2 - Bulk coarse sort through ‘mining’ of the stockpiles
Stage 3 - ‘The Recovernator’ provides the main sort of material
The state-of-the-art sorting plant at BRRP has been nick-named ‘The Recovernator’ to reflect the huge operation that is underway. It operates 16 hours every week day and 8 hours on Saturdays.
The residual waste from the bulk coarse sort will go through a combination of mechanical and manual sorting processes, including the automated recovery of selected materials by a variety ofscreens and mechanical/electrical devices.
The material received direct from the stockpile is put through a high powered shredder to reduce items to a suitable size for processing.
Fine material (predominantly soil) is recovered.
Magnets are used to recover ferrous metals and eddy current separators are used to collect nonferrous metals, whilst staff on a conveyor sorting line remove fibre (cardboard, paper), fittings, plastics and gib/plaster board.
Timber is recovered from a scraper bath, which separates the floating timber from hardfill which sinks.
After processing, up to ten different products are recovered for re-use, whilst residual waste is sent to landfill.