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FEATURE Disposing of treated timber posts
Trellising & Posts
Disposing of treated timber posts
Tackling a thorny issue for the winegrowing sector
Timber posts used to line vineyards the country over, providing necessary support to vine rows in rain and shine. The grim reality of these posts came, however, when it was time to replace them once they degraded. Harrison Davies spoke to those involved in efforts to find the posts a place to rest.
Wooden posts were once a go to for viticulturists looking for an easy material to line their Senior RD&E program manager at Wine Australia, Alex Sas, said there was space for a new approach for vineyards with. The issue with timber is that it’s an organic material and can degrade due to factors such as weather, pests and general decay. The solution way back in the 1930s was to treat the timber with a variety of minerals, most commonly arsenic and copper – a substance known as CCA. The substance was widely used and resulted in the commonly seen green tinged wooden posts that population the viticultural landscape. However the posts were found to be potentially toxic to people and produce in their vicinity. Wine Australia is currently conducting a survey to find where the treated timber posts are located and what producers have done with them. disposing of the old posts. “We need to know the approximate volume and condition of posts so that we can work with these businesses to develop regionally-specific options for growers looking to dispose or repurpose old posts,” he said. The use of CCA treatment went more or less un-noticed for decades until 2005 when the Australian Pesticides and Veterinary Medicines Authority (APVMA) released a report into its effects on people. The report laid out several suggestions for its removal, including its removal from children’s play equipment and also advocated for their removal from vineyards. While the research suggested the posts would not leach chemicals to the fruit themselves, there was evidence that As an organic matter, timber posts degrade from weather, pests and general decay • CCA was created in the 1930s to treat timber posts to improve their lifespan • The use of CCA-treated posts in vineyards went largely unnoticed for decades
• Some research suggests chemicals from treated posts could leach into surrounding ground • The disposal of treated posts remains a challenge • Growers have been warned not to burn treated posts • Used treated posts should be disposed of at an accredited waste facility • Potential health implications have led many growers to adopt posts made from materials like steel or plastic
AT A GLANCE
suggested chemicals could leach into the ground surrounding the posts. “New information, some from overseas and some from Australia, indicated that dislodgeable residues [those capable of being transferred from timber through contact] on CCA-treated timber structures may be higher than previously believed,” the APVMA report said. The potential for health implications
lead many wine producers to look toward changing their vineyard posts from the traditional timber to something more weather resilient, like steel or plastic, in order to remove the health risks the treated timber posed. Many producers removed their posts but remain with the challenge of disposing them.
Sustainable waste bodies like Green Industries SA warn against the burning of treated timber and state that any treated timber must be taken to an accredited waste facility rather than being burned. “[Wine businesses] in South Australia widely use CCA timber, leading to growing quantities of treated timber waste being generated and stockpiled,” a report by Green Industries SA states. “Given the recent global reviews of CCAtreated timber for toxicity risk assessment and leachate generation, the EPA promotes precautionary management of waste CCA timber.
“Burnt treated timber posts and treated timber ash is also highly hazardous. The heavy metals in treated timber ash present risks to ground- and surfacewater quality, human and animal health, and soil quality.”
Finding a place for old posts
Sas said the purpose of the survey was to develop methods and initiatives to responsibly remove posts from properties without causing further threats to vineyards and local environments. “While growers may think of old CCA and creosote posts as a waste stream, other businesses may consider them a resource that can be repurposed,” he said.
“The purpose of the survey is to get an idea of the likely stockpile of posts in each region. “The survey has already received lots of support from growers around Australia, which I’m really grateful for, but we need more responses to get a good picture of the volume and condition of posts in each region.” Wine Australia is working to map out a database of where posts in Australia are and what condition they are currently in. The survey is being conducted alongside the National Centre for Timber Durability and Design Life (NCTDDL) who focus on designing timber that not only has longevity but is also sustainable for people and for the environment. NCTDDL director and professor at University of Sunshine Coast Jeff Morell said the collaboration hopes to find a strategy to manage unused, treated posts. “The goal of the survey is to find out what they’re doing and figure out where they are,” he said. “The biggest issue is because you have a relatively low volume material and you have to be able to move it fairly efficiently. “There’s a lot of different options and you have to explore what might be best for the material and where it is.
“Some of the bigger stuff that we work with… you could take the poles and resell them and make timber out of them, which some companies already do, whereas some might be composted. “Then we’re talking to some mining refineries who might use it for bioenergy to replace coal.
Alex Sas
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“The other thing we’re looking at is pyrolysis in localised pyrolysis where you produce biochar for soil amendments is another possibility.” The survey also looks to find what producers have done to re-use posts in areas that are safe and functional.
One possible use for posts after their lifespan is to be used in fencing and landscaping, as they are still resistant to decay and insects. “The sector as a whole is working to improve its sustainability, and reducing carbon emissions and waste to zero by 2050,” Sas continued. “CCA and creosote posts are one of the products commonly used in vineyards and it’s a product that we need to consider for disposal or reuse in a way that will not create an additional burden on growers. “The survey results are the first essential step in developing a project to provide options for growers, which could include some uses for posts that have not previously been considered. “The goal of this project is to remove stockpiles of treated timber posts from grower’s properties, reducing the risks involved in storing them, for example the accidental release of toxins from old treated timber posts when burnt during bushfires.” There are several alternatives that are suggested for producers to use after removing their CCA timber posts. The first, and most common, is steel. This is a very resilient material and can be recycled many times. Despite higher initial costs, they are also easier to dispose of once they have completed their lifespan as they do not need to go to landfill and can be sold as scrap metal to recyclers. Another suggested material is recycled plastic composite. This material is typically made from waste materials gathered from residents’ recycling bins in local councils and actively uses waste materials to contribute to the circular economy whilst also diverting waste materials from landfill. Recycled plastic posts and plastic coated timber posts don’t rot, splinter, or weather with age or UV radiation and are impervious to pests like termites.. While the costs of these different materials may be initially higher than that of CCA timber, the cost of disposing them is far lower, and Green Industries SA warned producers that costs of disposing treated timber should be considered. “In South Australia, the only available disposal option for CCA posts is to send to a suitably engineered and licenced landfill,” The report stated. “The cost of sending CCA posts to landfill is an important part of considering the overall cost of ownership.”
Alex Sas
