New Method to Treat Plastic Waste

The first systems to use anaerobic digestion technology in order to turn waste plastics into energy and fertilizer are being developed in South Australia.

According to the information provided by, the plastic to energy technology had so far successfully been applied to polyethylene, polypropylene, polystyrene and expanded polystyrene. However, the anaerobic digestion process varied upon disposal feedstock and depended also upon temperature and system set up.

“The POET system prepares waste plastic in a way that microbial digestion can take place quickly and I think that’s really the key to making it a commercial opportunity,” the inventor David Thompson was cited. “I have already got inquiries from overseas including a large consortium in South America that is really quite interested to get involved and take the technology over there.”

POET Systems expects to have its first two machines – each capable of processing 20 tons of plastic a week – operating commercially in about 12 months. The first two POET machines (POET is an acronym for Polymer – Organic – Energy – Treatment) will be built at wastewater treatment plants in regional areas of the Australian state of Victoria. The same microbes will treat plastic and water simultaneously. The microbes then die and leave behind liquid and solid biomass, which can be used as fertilizer and biogas, separated into methane and carbon dioxide.

Thompson, who is based in the South Australian capital Adelaide, said the methane could be used to create heat and energy, possibly to power the wastewater plant, while there was also potential for the carbon dioxide to be captured and reused. “So basically the plastics go into an anaerobic situation in wastewater where the microbes digest the plastic and create energy,” he is cited. “This client in Victoria is big on wastewater treatment plants and after thinking about his methodology – there is over 550 wastewater treatment plants in Australia and at least half of those would have anaerobic digestion facilities attached so it is a good opportunity to go down that path.” Thompson plans to lodge provisional patent documents for the technology in the coming weeks. He said the system did not impact on existing recycling practices as it targeted plastics destined for landfill and would add a new revenue stream for companies in the waste industry. “People in the waste industry have already invested heavily in infrastructure so they know how to do the business. If this gives them an additional opportunity to make money and take on a segment which has not been handled before then I am happy with that.”

Australian Technologies Competition

POET Systems is a 2017 semi-finalist in the Australian Technologies Competition, which assesses, mentors and promotes companies providing a uniquely Australian take on the future and is open to technologies that have global potential in a range of industries. Winners will be announced at Technology Showcases in Melbourne and Sydney in October and November.

The short list says that “POET Systems’ plastic-to-energy technology allows for treatment and processing of plastics through Anaerobic Digestion using microbial transformation of the hydrocarbons to non-toxic fertilizers”.

Photo: O. Kürth

GR 32017