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A New Way To Make Plastic

In wastewater treatment plants in Belgium, the Netherlands, and Denmark, something unusual has been, and continues to happen. Anoxkaldnes, a subsidiary of Veolia, is running pilot prototyping for the production and recovery of Polyhydroxyalkanoates (PHA) – an intermediate material used to produce bioplastics.

Typically, wastewater would be viewed as pollution with the end requirement of treatment being to reduce the potential harm it causes, but the innovative work within Veolia is actively aiming to transform wastewater into a raw material feedstock.

Most plastics are derived from finite sources of petroleum or natural gas. Currently, low oil prices keep the cost of virgin petro-based plastics down, but market prices have been volatile for the last decade and future costs remain uncertain as fossil fuel stocks become less secure.

Licensed under CC - credit Flickr user: dotjay
Licensed under CC – credit Flickr user: dotjay

Traditional petro-based compounds are also challenging to deal with at end of use. They are not biodegradable and plastic products often involve complex and almost inseparable mixes of materials. Even when recycling is possible, the process often involves a downgrading of the quality, which means that the number of reuse cycles is limited.

Biodegradability is not ubiquitous in bioplastics, but those being derived from wastewater by Veolia are a bio-sourced and biodegradable alternative to traditional plastics. The properties of PHA are similar to those of polypropylene, which is usually found in packaging, carpets, stationery and several other everyday products. Notwithstanding PHA based bioplastics offer longer-term positive opportunities in products and services as an alternative to polypropylene today.

It turns out that organic residual streams, including sewage, contain all the necessary ingredients for biopolymers to be created. The ideas have existed for more than a couple of decades, but since 2007, in the laboratories of Anoxkaldnes, the creation of polymers by bacteria in wastewater has been advancing to practical reality.

The researchers have optimised ideas of natural selection in bioprocess in order to couple wastewater treatment, which uses naturally occurring bacteria in treatment processes, with the creation of biomass that is PHA-rich. The PHA polymers in the biomass can then be refined into biodegradable bioplastics that are 100% sourced from wastewater.

Jacob Bruus, Executive VP of Veolia Water Technologies AB – Anoxkaldnes Technologies, told Circulate that there are concrete opportunities for bioplastics to replace conventional plastic uses and beyond, “PHA – biopolymers can be formulated into bioplastics, and these can be used over a wide range of applications – from specialty packaging to functional agro-industry products and services”.

Economic viability is dependent upon getting to scale. Bruus commented, “At present we estimate that a plant with a capacity of 5,000 t PHA/y will be commercially viable”. The world’s largest bioplastics facilities currently are with reported capacity to produce 10,000-15,000 tonnes per year. He added that the raw material used for the production is considered to be waste and would usually come with a cost for disposal, and was optimistic about the supply of this raw material:

“We do not expect limitations production wise, as the enriched biomass (biomass containing PHA) can be produced on several wastewater treatment plants feeding a central polymer extraction site. In this way the supply of raw material will be unlimited.”

Of course, in the context of cheap oil prices and virgin plastics, bioplastics – even those created from wastewater – will struggle to be commercially competitive in the market. The long-term picture for the use of this technology is very promising, but the more immediate utilisation may well depend upon other regional policies and incentives, as is the case with the recycled plastics market more broadly.

There are incentives for companies to make this shift now. The last year has seen an increase in research and activity relating to the natural capital value of the ocean and the damage caused by plastic waste. Momentum behind legislative and business action on the issue of plastic pollution is growing and when it happens, it could impact the market.

Simultaneously, there is also growing support for international action to reduce CO2 emissions ahead of the COP21 summit in Paris in November. The manufacturing of plastics is a CO2 emitting process with estimates ranging from 100 million to 500 million in terms of tonnes per year emitted from production processes in the U.S. alone. That means that the CO2 in plastics production could be equal to as much as 45% of the total annual emissions from motor vehicles in the U.S. If fees or the pricing structure of carbon is changed, then the impacts will be felt by producers of raw petro-based plastics.

Looking through the lens of a circular economy, it is clear that the system of petro-based plastics is not operating effectively in terms of its negative effects and its over-reliance upon finite resources. It’s a system that is facing increasing challenges with limitations that are gradually being acknowledged.

Bioplastic derived from wastewater. Photo credit: Alkistis Kokoikou
Bioplastic derived from wastewater. Photo credit: Alkistis Kokorikou

The discovery of new feedstocks like wastewater are valuable in further making the economic case for the increasing the production of biodegradable plastics and Veolia’s commitment to the development and piloting of this new technology is a further suggestion that business is looking at a different system for the production of renewable resources in the future.

The development of wastewater bio-plastics creation may only provide a relatively small percentage of the global plastic packaging picture, but the development of an effective system for the manufacture and effective cycling of plastics, both petro-based and bio-based, is likely to require a more complex mix of solutions.

In order to address plastic flows on a macro-level, Veolia is also a part of the Ellen MacArthur Foundation led, and World Economic Forum supported, Global Plastic Packaging Roadmap – one of the flagship initiatives of Project MainStream. The plastic packaging roadmap will be developed in collaboration with city governments and packaging manufacturers and designers to create a new system where plastic packaging never becomes waste, but instead cycles through the economy as either a technical or biological nutrient.

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The Author

Seb Egerton-Read

Seb Egerton-Read

Seb writes daily content for Circulate across the full spectrum of the website's topics. Previously he has spent five years as a freelance writer for a number of websites and blogs. You can e-mail Seb at seb[at]circulatenews.org