The Circular Economy – something for everyone

James Clark from the University of York looks at the Circular Economy and its implications for sustainability.

The truly universal significance of the circular economy concept – today’s waste needs to be tomorrow resource – was brought home to me recently when I collected my car from a local small garage and the owner told me that he is now being offered about a quarter of the full price for old car batteries. The metals in batteries – and so many other common items are becoming valuable enough and scarce enough to make waste electronics and other metal-rich wastes a valuable commodity. It makes sense that rather than rely on a diminishing resource, mostly from regions where either local environmental, labor or political issues make supply problematic, let’s make better use of what we have on our doorstep – and we all have a lot of waste! But is this only an issue for waste electronics and electrical equipment (WEEE)?

Circular-leafNot at all – we have created a society based on the linear economic model of extract-process-consume-dispose and whether it’s organic carbon to synthesis a dye molecule or indium to manufacture a mobile phone, the same unsustainable model applies. And not only do we convert a precious and limited resource to a waste – sometimes very quickly – we also treat that “waste” in such a careless way that it damages the environment we all share (see for example, the plastic islands in the Pacific ocean).

Circular-arrowHow can the Circular Economy improve things? The basic premise is that we should ensure the resources embedded in every item we consume are returned to us for further use at the end of the useful lifetime of the item. Most circular economy models do this either via the natural bio-sphere (typically for organic substances) or via the man-made techno-sphere. I would go further and suggest that in theory if every resource was ready-for-reuse within 100 years of its original build, and assuming we can build everything a static population could want from existing and (reasonably easily available resources), we would achieve sustainability. Of course this is only theoretical – it assumes we don’t consume more resources or have any materials losses in the recovery phase, as well as assuming we capture all items for reuse. These are enormous assumptions that are unjustified in the basis of experience but let’s for the sake of argument, assume we can be 80% efficient in these processes. This then requires that we continuously improve our resource efficiency by 20% or we increase our resource pool by exploiting our existing wastes. LandfillWaste is an enormous resource that we have been accumulating over a long period and while much of it is dispersed, we do have concentrations in landfills for example. How much can we do with this existing waste is unclear but landfill mining is on the agenda in many national and international discussions and could well make a significant contribution to the resource deficit while relieving our serious waste accumulation problems.

Interesting organic waste-turned-resource opportunities include plastics and food supply chain wastes. Both of these are very large volume, present a serious problem to society, and have some degree of waste management already in place. Plastics is a major waste opportunity: worldwide we only recycle about 1% of the plastic we use, yet plastic manufacture consumes some 10% of all the oil we consume, and much of it causes serious environmental damage through negligent release (eg in the oceans). Plastics tend to be chemically quite simple (the largest volume plastics are polyolefins) and ideal as feedstocks for the existing petrochemical industry as long as we can crack the polymers with some selectivity and reasonable energy efficiency. The logistics are not helpful however, with plastics widely distributed into numerous applications ranging from short-lived packaging to long lifetime construction and transport. It might however, be interesting to see where large volumes of waste plastic are already concentrated and if these would translate into large enough quantities of small molecule chemicals (alkenes, etc) to be useful.

fruitFood supply chain wastes are already concentrated in certain regions including major growing areas and major food processing centres. Harvesting fruits, vegetables, beverages and cereals can lead to substantial volumes of low value by-products while downstream, the processing of foods such as fruit juicing, the extraction of actives, and food freezing leads to major quantities of unwanted residues. While much of the (UN estimated) 1+ billion MT of edible food waste may be dispersed in households and shops, much of the even larger quantities of inedible (peels, stones, shells etc) and rejected food supply chain wastes are concentrated and therefore, easier to valorize. The chemical content is more complex and varied than in plastic waste but that can be a good thing, offering valuable extracts (waxes, terpenes, etc) as well as important classes of compounds with high market demand (flavonoids, sugars, phenolics, etc) and valuable bulk components including starches and pectin. This complexity would lend itself to future, zero-waste bio-refineries making chemicals, materials and fuels.

We cannot achieve sustainability and ignore our waste legacy. In reality the best we can expect is to move slowly (but hopefully surely) towards a circular economy model while simultaneously learning how to valorize (at least some of) our accumulated wastes. For both of these, we need a full and determined partnership between industry, government and the public – industry needs to embrace the concept of new feedstocks and the new technologies needed to valorize them, governments need to ensure that legislation isn’t interfering with its utilisation (eg on waste labeling and movement) and that policy is supportive, but ultimately we all need to understand and support the fundamental belief that waste is not sustainable.

James Clark, York, June 2014



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