May 29, 2002
From waste to worth:
By Jennifer Llewellyn, OMAFRA Nursery Crops Specialist and Carl Fletcher, OMAFRA Strategic Business Planning Program Lead
A plastics recycling case study
New technologies in the development of plastic building materials are creating end-use possibilities for used plastic films from the horticulture industry. This could mean some exciting alternatives for the fate of an estimated 400 tons of polyethylene film produced by the Ontario nursery industry each year (Figure 1).
Information from the 2001 Toronto Plast-Ex Trade Show indicate plastic lumber products supply four to five per cent ($200 million U.S.) of the North American deck and outdoor furniture market annually, and increase this market share at a 50 per cent annual growth rate. Examples of plastic building materials range from stainable, hardwood style flooring strips to wallboard. Both virgin and recycled plastic film can be used in the manufacture of plastic building materials. Companies vary on their use of recycled plastic depending on their manufacturing process, the availability of recycled plastic, the collection costs and the market price of virgin plastic resin. Obviously, the costs associated with the cleaning and pre-processing tasks for recycled plastics make virgin plastics a cheaper and simpler alternative. However, recent increases in energy prices have raised the cost of virgin plastic resin, creating a renewed interest in plastic recycling alternatives.
Among the North American-based manufacturers using recycled plastics, Wellington Polymer Technology Inc. (WPTI) of Guelph and Chatham, ON, use plastic to create usable products for the housing industry. WPTI’s development of the Enviroshake adds a new dimension to the plastic building material industry. The Enviroshake resembles a weathered cedar shake shingle and can be manufactured using recycled greenhouse film as one source of plastic. WPTI was approached a few years ago to look at the viability of incorporating used Ontario horticultural polyethylene films into their production. They conducted the necessary feasibility studies, with the help from programs such as CanAdapt and IRAP, to determine if the used polyethylene film was suitable for their processing and product. The research was successful and gave WPTI the incentive to collaborate with producers of horticultural plastic films.
Connon Nurseries (NVK Holdings) has and continues to be actively involved in the development of practical on-site handling and collection systems as a key step for their nursery to become “recycling ready.” This past spring, Connon (NVK) and WPTI worked together to develop a material exchange system that meets the needs of both the grower and the end-user. WPTI left a tractor-trailer on site to collect plastic from Connon (NVK)’s large number of polyhouses. This way, the nursery could remove and bale plastic when it was convenient, and contact WPTI to pick up the plastic, at no cost to the grower. Growers with much smaller loads of plastic would need to store the bundles for a week or so until WPTI could send a truck for pick-up. The other alternative is to arrange a pick-up window that includes plastic from neighbouring growers. From there, WPTI could take the used plastic to their new warehouse in Chatham, where it will be stored until it is prepared for processing.
A few years ago, IRAP helped to develop a spindle roller that can be used for bundling used plastic from polyhouses. One model was developed for the nursery industry. Connon (NVK) took this design and improved upon it, making the spindle collapsible for easier extraction of the bundle (Figure 2). They also added hydraulic power to the unit, taken from the tractor’s hydraulic system (Figure 3). Now, only a few employees are needed to run the roller system, ensuring the plastic lies flat and is wound up as tightly as possible (Figure 4). Connon (NVK) uses only 100-ft. sections of plastic for easy handling (Figure 5).
WPTI can recycle all types of polyethylene films used in horticulture (including the clear and opaque plastic used in container nursery production). Recycled plastic films need to be as clean and dry as possible and free from stones or sticks to be reused for further processing. Usually, only the aboveground plastic is acceptable.
Although some of the used plastic from nursery production is sent to the landfill, much of it is re-used in other aspects of plant production. Sooner or later, however, it ends up as waste. The recycling of plastic films from horticultural production is a positive and productive step towards environmental responsibility and commitment of our industry. WPTI is looking for more sources of horticultural plastic. For more information, please contact Wellington Polymer Technology Inc. at 519-380-9265.