By Pat Pepper
NCWQ Environment Adviser
Plastic Waste –Problem: In 2015 global plastic production reached 322 million tonnes (Mt), a dramatic increase compared to the 279 Mt produced in 2011. The plastics demand in the European Union was 58 Mt, of which 29.7% was recycled, 39.5% was recovered in the form of energy (mainly incineration) and 30.8% was sent to landfill Kalargaris, Ioannis Guohong Tian, Sai Gu The utilisation of oils produced from plastic waste at different pyrolysis temperatures in a DI diesel engine Energy 131 (2017) 179e185; Association of Plastic Manufacturers Europe, Plastics e the Facts 2016. An analysis of the European plastics production, demand and waste data. European Association of Plastics Recycling and Recovery Organisations; 2016 p. 1e38. Geyer et al estimated that 8300 Mt of virgin plastics had been produced between 1950 and 2015, of which 30% was still in use. They estimated that in 2015, 407 Mt of primary plastics (plastics manufactured from virgin materials) entered the use phase, whereas 302 Mt left it. Thus, in 2015, 105 Mt were added to the in-use stock. The cumulative waste generation of primary and secondary (recycled) plastic waste amounted to 6300 Mt of which around 9% had been recycled, 12% incinerated, and 79% accumulated in landfills or the natural environment i.e. about 60% of all plastic ever produced is in landfill or litter. Four to 12 Mt of plastic waste generated on land was estimated to enter the marine environment of all major ocean basins in 2010. Geyer et al also noted plastics’ largest market was packaging most of which leaves use the same year they are produced
Geyer, Jambeck, Law Sci. Adv. 2017;3: e1700782; (DOI: 10.1126/sciadv.1700782)
The fate of plastic packaging material is illustrated below. With 78 Mt of plastic packaging used in 2013, only 14% was collected for recycling, 14% incinerated and the remaining 72% ended up in landfill or as litter in the environment
GLOBAL FLOWS OF PLASTIC PACKAGING MATERIALS IN 2013
World Economic Forum, Ellen MacArthur Foundation and McKinsey & Company, The New Plastics Economy — Rethinking the future of plastics(2016, http://www.ellenmacarthurfoundation.org/publications).. https://theconversation.com/the-new-100-recyclable-packaging-target-is-no-use-if-our-waste-isnt-actually-recycled-95857
Health and Environmental Issues: Toxins in or attached to microplastics can embed themselves in the marine food chain. The smallest plastic particle, nanoplastics, can carry larger amounts of environmental toxicants due to their high surface/volume ratio and can enter organs and body fluids of marine or land organisms and could be a risk to humans if digested. Supporting information for submissions on micro and nano plastics from NCWA & NCWQ Environment Adviser, Plastics, such as ethylene and propylene, derived from fossil hydrocarbons, are not biodegradable and as a result, they accumulate, rather than decompose, in landfills or the natural environment. Geyer et al ibid Over the very long term landfill would result in production of greenhouse gases through slow decomposition of plastic in a putrescible landfill. Final-report-Panel_Hume-Waste to-Fuel-Facility.pdf
Strategies to combat this waste problem include avoiding products becoming waste (reduce and reuse); finding an alternative use for waste (recycle and recover); and as a last resort, disposing safely. Unfortunately landfill can be the default for the latter..
Reduce and Reuse: There can be no argument about reducing plastic waste, like using alternative material to plastic e.g. hemp bags instead of plastic bags for shopping. However, there is a proviso on continual reuse of plastic containers. For example to make the plastic flexible, phthalates might be used in the manufacturing of plastic bottle. Phthalates are endocrine disruptors, a major environmental concern, and which can mimic the actions of hormones in the human body. https://www.thoughtco.com/safest-type-of-water-bottle-1203973
Recycle and Recover: The Plastics Identification Code (PIC) identifies the type of plastic resin a product is made from, its properties and possible use when recycled.
|Examples of plastic products||Characteristics||Examples of recycled plastic products|
|PET/PETE – Polyethylene Terephthalate||Soft drink bottles, sleeping bag filling||Clear, rigid, often used as a fibre||Soft drink bottles, clear film for packaging|
|HDPE – High density Polyethylene||Milk bottles, crinkly shopping bags||Hard to semi flexible, usually opaque||Wheelie bins, detergent bottles, agricultural pipes|
|PVC – Polyvinyl Chloride||Cordial and juice bottles
Shoe soles, garden
|Flexible, clear and semi-elastic||Pipes, tiles
Hose cores, industrial flooring
|LDPE Low-density Polyethylene||Ice cream lids, garbage bags||Soft and flexible, waxy surface||Freezer bags, plastic packaging|
|PP – Polypropylene||Ice cream containers, crisp packets||Flexible but strong||Compost bins, worm farms|
|PS – Polystyrene
EPS Expanded Polystyrene
|Yogurt pots, plastic cutlery, hot drink cups, take-away containers||Rigid and brittle, clear or glassy looking, lightweight and foam-like||Clothes pegs, coat hangers|
|All other Plastic||All other plastics Includes acrylic and nylon||Varies||Imitation timber and concrete products|
Cleanaway Fact Sheet
However, these numbers do not mean that the items are automatically recyclable. The PIC tells recyclers what type of plastic a product is made from. Not all plastics are recyclable e.g. hard thermoset plastics commonly used in electronics. Even those plastics that are recyclable often need mechanical or hand sorting into separate plastic polymer classes before they can be processed. Currently only three of the seven categories are economically viable to recycle: PET (soft drink bottles); HDPE (milk bottles); and PVC (shampoo bottles). The other four – LDPE (garbage bags); PP (microwaveable cookware); PS (foam hot drink cups); and other plastics are less economically viable and so are recycled at much lower rates. https://theconversation.com/the-new-100-recyclable-packaging-target-is-no-use-if-our-waste-isnt-actually-recycled-95857 Incentives like supplying labelled bins in convenient locations could encourage the public to sort their own plastic waste. Contamination can be a problem.
Effect on human health and the environment: Recycled plastics aren’t able to continually serve the same purpose after recycling. The process of melting down and recycling plastic produces volatile organic compounds that can harm plant and animal life including humans near the industrial site if not carefully controlled. Plastic is manufactured from petroleum and this substance can leech into foods stored in recycled plastic containers. Plastic manufacturers only use a small portion of recycled plastic, if any, when producing food containers and packaging. Because of the potential health threats recycled plastic poses, much plastic recycling is actually downcycling e.g. a plastic water bottle may be downcycled to become artificial turf or plastic furniture.https://sciencing.com/disadvantages-recycled-plastics-7254476.html
Market for recycled plastic: Lack of market for recycled plastic can be a disincentive. One recycling business which turns soft plastics such as milk cartons and squeezable shampoo bottles into sturdy plastic play equipment, termite-proof boardwalk decking and bollards, processes about a third of what it has the capacity to. This firm with at least one other only accepts plastic waste from organisations willing to buy back the recycled products. https://www.theguardian.com/sustainable-business/2017/may/22/recycling-in-australia-is-dead-in-the-water-three-companies-tackling-our-plastic-addiction.
The Federal Government is to be commended for negotiating with the State and Territory Governments for a target of 100% of Australian packaging to be recyclable, compostable or reusable by 2025. The Australian Packaging Covenant Organisation, working with its 950 member companies are to deliver this target. However, the definitions of different waste categories vary by state and territory, so there is no commonly accepted working definition of what constitutes “recyclable, compostable or reusable”. Because some products that are technically recyclable are not accepted in most councils, kerbside recycling collection the target is unlikely to be met without policies and market incentives. e.g. Almost 80% of glass and plastic bottles are recycled in SA which has container deposit legislation compared to 65% in WA where similar legislation is only at the discussion stage. Atiq Zaman, Curtin University, advocates
- legislation, regulations or incentives for manufacturers to develop new packaging types;
- an increase in public participation rates in recycling; and
- the development of a strong domestic market for recyclable materials.
Conversion of plastic waste to fuel: Geyer et al note the vast majority of monomers used to make plastics, such as ethylene and propylene, are derived from fossil hydrocarbons. None of the commonly used plastics are biodegradable so they accumulate, rather than decompose, in landfills or the natural environment. The only way to permanently eliminate plastic waste is by destructive thermal treatment, such as combustion or pyrolysis. Geyer et al, ibid
The pyrolysis process to convert plastic waste to oil, the suitability of various plastics for this process and some of the commercial machines available to do this have been reported previously. Some types of plastics e.g. pure hydrocarbons, such as polyethylene (PE) and polypropylene (PP) are more suitable than others for using this technology NCWQ Environment Adviser’s Reports, February 2018 Many Australian jurisdictions specify that the waste sourced as input for waste to energy plants must target genuine residual waste that cannot feasibly be reused or recycled. Final-report-Panel_Hume-Waste to-Fuel-Facility.pdf A commercial scale facility capable of converting waste plastics to fuel at a rate of 50 feedstock tonnes per day was commissioned in NSW by Integrated Green Energy (IGE) with Foyson Resources using a catalytic restructuring process. http://plasticpyrolysisplants.com/50-tpd-plastics-to-diesel-plant-produces-first-batch-in-australia/ However, in a Report to the ACT Minister for Planning and Land Management on the Proposed FOY Group plastic to fuel facility in Hume industrial zone, an independent panel noted the IGE proposal was not supported by NSW EPA as the “proof of performance” requirement in the NSW Energy from Waste Policy was met. Final-report-Panel_Hume-Waste to-Fuel-Facility.pdf The company also planned a plastics-to-fuel plant that would convert 73 tonnes of plastic into 77.5 million litres of fuel a year to be built at Hume in the ACT. The company claimed their technology removed ash, dealt with hydrocarbon contaminants, and used waste gas for heating to burn off gas at a high enough temperature to destroy noxious compounds. https://www.canberratimes.com.au/national/act/foy-group-walks-away-from-plasticstofuel-plant-in-hume-20180114-h0i0qw.html The independent panel reported the company’s environmental impact statement failed to sufficiently address key risks, including the risk of explosions, the potential damage to surrounding land, and the effects on air quality. They also recommended ACT should have a “proof of performance” requirement. Hence the plan was shelved. https://the-riotact.com/foys-planned-oil-refinery-has-hit-a-major-obstacle/202920 Recently, Integrated Green Energy Solutions (IGES), announced a joint venture agreement with the Chinese Crown World Holdings to construct a waste plastic-to-fuel facility in Weifang in Shandon Province of China. The facility will have an initial production capacity of 200 tonnes per day, producing 70 million litres of road-ready fuels per annum. IGES’s patented plastic-to-fuel process is claimed by the company to reduce the environmental impacts of waste plastic, that would otherwise be used in landfills or discarded into the environment. .http://www.manmonthly.com.au/news/australian-company-convert-chinas-waste-plastics-fuel/ The Hume-Waste to-Fuel-Facility Panel also noted that most proposed energy from waste facilities in Australia have not progressed to a commercial operation due to unanticipated complexities dealing with contamination in the mixed waste stream, resulting in mechanical handling problems, plant damage or failure to reliably comply with contemporary air emission standards. An additional complication can be the challenge of maintaining a sustainable product in a marketplace where this competes with conventional products, and is influenced by world oil prices. Final-report-Panel_Hume-Waste to-Fuel-Facility.pdf Maybe, given the waste disposal problem exasperated by China’s ban on imported solid waste, the need for sustainable continuous energy supply and that Australia only has 48 days aggregated fuel reserves, the limitation on resin type to be used in waste to energy plants should be reconsidered.
Another method of producing fuel from plastic waste is Gasification which involves heating the waste plastic with air or steam, to produce a valuable industrial gas mixtures called “synthesis gas”, or syngas. This can then be used to produce diesel and petrol, or burned directly in boilers to generate electricity http://theconversation.com/if-we-cant-recycle-it-why-not-turn-our-waste-plastic-into-fuel-96128
However pyrolysis is reported to have better advantages towards environmental pollution and reduction of carbon footprint of plastic products. Pyrolysis minimizes the emissions of carbon monoxide and carbon dioxide compared to combustion and gasification. A review on thermal and catalytic pyrolysis of plastic solid waste https://www.sciencedirect.com/science/article/pii/S0301479717302992