Films | Flexibles | Bags
Films | Flexibles | Bags A New Mater-Bi Grade for Garden Waste Collections: A Specifically Taylor-made Application Article contributed by Christian Garaffa Project Manager for Source Separation Novamont S.p.A., Novara, Italy Garden Waste Bag made from Mater-Bi Besides other Mater-Bi ® grades for smaller biobags made for kitchen waste collections, Italian supplier Novamont has also developed a different material specifically designed for the production of sacks for the collection of garden waste. Of the total amount of waste produced in Europe, approximately 20% is garden waste. A remarkable figure. Garden waste collections using wheeled bins are wide-spread in quite a number of countries yet there are still wide margins of improvement (e.g. Germany is collecting nine million tons of food and garden waste but there are still five million tons to be captured i.e. diverted from landfill). Many of the collection schemes are only available in certain areas. Restricted access to such collections has an impact in terms of the amount of biodegradable waste going to landfill but also to residents who do not receive the service. There are many factors which limit where such collection schemes can be implemented including: access to gardens e.g. steps, lack of storage space, collection vehicle access down narrow or dead-end streets and cost. The perfect complementary solution for such circumstances is to provide residents with compostable garden waste sacks. They are easy to distribute, store, meet the European standard for compostability and are ideally suited for free and charged schemes. Garden waste sacks made with Mater-Bi are available in a range of sizes to fit different needs and to meet health and safety requirements. To ensure collection crews can easily identify which bags are acceptable, Mater-Bi bags can be manufactured with specific and easy to identify printing. An example for this is the ‘beehive pattern’ accepted by several local authorities in different German federal states. The reason for Novamont developing a taylor-made grade for this application is that by its nature, garden waste (especially grass clippings) is biologically active and aggressive, so it is vital that collection bags can withstand high levels of biological activity whilst maintaining their strength for at least two weeks (i.e. the usual collection frequency for this waste fraction). This material also has a high resistance to piercing, ripping and tearing. It is made using renewable raw materials like vegetal oils and biodegradable and compostable polymers. It is fully biodegradable when introduced into biologically active environments like industrial composting plants. The biodegradation process is affected by temperature, humidity, pH and substrate activity. The conformity with EN 13432:2000- 12 is certified by third parties like DIN Certco or Vincotte in Europe. The maximum certified thickness is 100 µm. The manufacturers do usually produce sacks of thickness between 25 and 30 micron. This guarantees a resistance of over two weeks from the moment the bag is filled with garden waste and a maximum weight load of 18 kg. www.novamont.com 12 bioplastics MAGAZINE [06/08] Vol. 3
Films | Flexibles | Bags An evaluation of agricultural mulch film made from biobased PHA polymers (Mirel from Telles, Lowell, Massachusetts, USA) was conducted by Professor Michael D. Orzolek, Department of Horticulture at Pennsylvania State University. The study provided preliminary observations regarding vegetable crop growth response in both open-field and high-tunnel environments using both Mirel mulch films and polyethylene mulch films. The open field experiments were conducted with Zucchini Squash and Bell Peppers, and high tunnel experiments were conducted with Patty Pan Squash. The observed results in vegetable crop yield, both in number of fruit harvested and in the mass of each harvested fruit, with PHA mulch films were similar to crop growth with polyethylene mulch films. Performance of Mirel Mulch Film made from Mirel in Agricultural Mulch Film Applications High Tunnel: Squash 80 Issues with Non-Degradable Films Mulch films are left on the ground for extended periods of time, including multiple growth cycles. The disposal of mulch films after crop harvest has been and will continue to be a considerable concern. Removal of conventional mulch films is difficult because films can tear during retrieval and are labor intensive to remove. The film itself is heavy because it has up to 40% by weight of soil and water. Residual pesticides are also present on the film. Interim storage of used mulch film and final transportation also adds more complexity. One option is to dispose of mulch films and agricultural plastics in landfill sites. However, landfill disposal is under increased pressure due to limited landfill space, escalating costs and increasing scrutiny on environmental impact of agriculture. Recycling is also an issue because these films have entrapped dirt, soil, plant debris and moisture; it is more challenging and requires an extra wash step to remove dirt and debris. The United States Environmental Protection Agency (EPA) reports that their hierarchy of solid waste management considers landfill disposal options to be less desirable than source reduction, recycling and composting. When comparing biodegradable mulch films to conventional films, the costs of purchasing the films as well as cost savings for removal and disposal should be considered. PHA Biodegradability Benefits Mirel mulch films were ploughed into the soil after the crop harvest, eliminating the environmental and cost concerns regarding mulch film retrieval and disposal. A key feature of PHA is its biodegradability by naturally occurring microbes in soil at ambient temperatures making these films well suited for agricultural mulch applications. In addition to the biodegradation, the material considerably reduces environmental impact as it is biobased, made from corn sugar. Because landfill disposal and recycling are the most commonly employed means of disposal for polyethylene mulch films, natural biodegradation of ploughed-in biobased films are not only an eco-friendly alternate but also a more efficient and easier farming practice. www.mirelplastics.com Total # Fruit Harvested Weight (oz/fruit) 60 40 20 3.4 3.3 3.2 3.1 3.0 2,9 2,8 Bare Ground P E Mulch Mirel Mulch Bare Ground P E Mulch Mirel Mulch Patty pan squash crop yield data for the high-tunnel experiments. Pattypan Squash (Petit Pan Squash) Source: Wikipedia bioplastics MAGAZINE [06/08] Vol. 3 13
