Building out waste – Tackling construction and demolition waste is critical to Zero Waste to Landfill targets, writes Parul Sood.
By the end of the 2018/19 financial year on June 30, Auckland’s construction and demolition (C&D) sector had produced an estimated 570,000 tonnes of waste. That’s the equivalent of 196 storeys with the same area as the Auckland Town Hall filled to the brim with waste. C&D waste accounts for 50 percent of Auckland’s total waste stream going to landfill: a volume that is similar to national figures.
Auckland region’s C&D waste is projected to grow by three percent per annum and, currently, C&D waste generation in Auckland is tracking around two years ahead of projections.
Territorial authorities around the country face a big task in turning the tide on C&D waste. Lack of awareness around the amounts of construction waste produced remains a key barrier to tackling the problem with the sector.
Additionally, the high levels of current construction activity nationally, and especially in Auckland, mean it’s difficult for the industry to find time to change existing practices.
Councillor Penny Hulse, chair of Auckland Council’s Environment and Community Committee, says C&D waste was identified as one of the region’s three priority commercial waste streams under council’s 2018 Waste Management and Minimisation Plan (WMMP). It was prioritised due to the high tonnage going to landfill and its diversion potential.
“The volume of C&D waste being generated is only the start of the challenge,” she says. “From a circular economy perspective, the fact that valuable resources are being sent to landfill, when they could be recovered and re-used or re-sold to create wider economic and social gains, is a serious lost market opportunity.
“The carbon emissions’ impact of these materials being landfilled is also problematic when we consider the pressing issue of climate change. Aucklanders are asking for action on environmental issues, waste minimisation and climate change, which is why we have set the target of Zero Waste to Landfill by 2040.”
Birkenhead War Memorial Grandstand, Auckland
Auckland Council has gone circular on a demolition project to divert construction waste from landfill.
In November 2018, the council engaged two contractors to complete the deconstruction of the Birkenhead War Memorial Grandstand in Birkenhead.
Green Way led the deconstruction and Trow Group worked on salvage aspects of the project, with the aim of diverting 85 percent of the building materials, fixtures and fittings from landfill.
The grandstand was built in the 1950s but had become structurally unsound, due to rusting in the base of the steel portal frames, and so needed to be demolished for health and safety reasons.
All easily recoverable materials, such as metal, concrete and timber, were segregated onsite. All other recoverable, co-mingled construction materials were sent to Green Gorilla.
Timber recycling company The Kauri Warehouse recovered approximately 535 lineal meters of matai cladding and flooring. These were reprocessed and sold for recycled feature flooring.
Salvaged items recovered by Trow Group were distributed to community groups and schools in New Zealand and Tonga. A lot of items were used locally at a new church build in south Auckland.
The group also employed and trained people in the community to assist with the deconstruction and soft strip.
C&D waste disposal will cost the Auckland-based industry around $100.2 million this financial year, based on the average tonnage cost for Auckland transfer stations ($180 per tonne). Note that the figure excludes an estimated 2.2 percent of waste from KiwiBuild/HLC. Large suppliers such as demolition companies can get rates much lower – as low as $95.00 per tonne.
Over 80 percent of waste disposal costs is in the top three material types: $38 million on special/potentially hazardous waste, $37 million on rubble and concrete, and $22 million on timber. Timber is an easy win for the industry – the archetypical low-hanging fruit.
Waste disposal costs are set to continue to rise, according to Penny. So, it makes sense for the C&D sector to start thinking about reducing C&D waste.
“Territorial authorities have been strongly advocating for changes to the waste levy – both in terms of the cost and the scope of the levy – as a lever to encourage waste minimisation, especially in the commercial sector,” she says.
“Any changes to the levy will drive up costs for disposers. As the city’s footprint expands, waste transportation costs will also increase due to higher fuel and labour costs, because of traffic congestion, and travel distances and times to landfill sites. So, building out waste is both the smart thing and the right thing to do,” she says.
“Compliance and regulatory costs may rise as public expectations increase for councils to take action against building contractors who do not manage their waste on construction sites.
“With heightened construction activity, there is a high degree of public scrutiny of construction site run-off polluting local waterways and instances of littering, illegal dumping, and building waste spilling into public spaces.
“Offenders also face the economic impact of reputation and opportunity loss when they fail to comply with bylaws and regulations.”
Auckland Council is working with the waste minimisation and resource recovery sectors and the Auckland construction industry to begin to turn back the dial on C&D waste.
Four key areas have been identified as priorities:
- a new approach to design out waste from the outset of the design and planning process for a project;
- a focus on procurement to get quantity surveying and buying right so that waste is built out during this phase of the build process;
- building a site-specific waste plan into project contracts so that building materials are actively recovered on demolition sites during the deconstruction process; and
- educating people working in the sector about sector-related waste and how they can play a role in reducing the amount of waste sent to landfill.
Auckland Council has also stepped up to reduce its own C&D waste by testing different approaches on council construction and demolition projects around the region.
“We have two council waste-related targets set out in our 2018 WMMP, one of which is to work across council to set a baseline for operational wastes and, by 2019, put in place targets for reduction. This includes C&D waste,” says Penny.
To walk the talk in the C&D space, Auckland Council is working to adopt a deconstruction and soft strip approach as a standard, instead of following current demolition practices.
The deconstruction methodology sees buildings carefully taken down, bit by bit, to recover materials so that they can be re-used elsewhere. This includes fittings and fixtures as well as important building componentry and materials.
“Deconstruction practices allow us to extract and recover valuable construction materials from buildings. It’s another way for us to support a circular economy that re-uses resources and diverts construction waste from landfill,” says Penny.
For its new build projects or renovations/redevelopments, Auckland Council has developed a site-specific waste plan specification and is working to adopt it as a standard that
an be included in contracts to ensure that waste minimisation and diversion of waste from landfill are key contract deliverables.
Auckland Council’s Waste Solutions Team and Research Investigation and Monitoring Unit (RIMU) recently worked with council’s chief economist to understand the financial costs and benefits of implementing deconstruction and waste minimisation methods and practices in residential building developments.
The cost-benefit analysis tells a positive story. It shows the benefits of minimising construction waste, the value in sorting and separating leftover building materials for re-use or re-sale, and the social and economic gains that can be achieved from using deconstruction and soft strip techniques.
The numbers stack up. For every dollar spent on waste minimisation, there is a minimum return of 0.97, with the potential to reach a cost-benefit ratio of 2.9. This puts money back in the pockets of construction industry players and reduces waste at the same time.
The study showed that diversion rates from landfill of 70 to 90 percent were achievable on demolition projects if deconstruction and soft strip methodologies were employed.
Results revealed salvaged materials could earn between $4000 and $20,000 in returns.
• Parul Sood is programme director – waste solutions at Auckland Council.
This article was first published in the July 2019 issue of NZ Local Government Magazine.