At its Lelystad site in the Netherlands, Renewi subsidiary Orgaworld has commissioned a hydrolysis container that produces bioplastics from organic waste. It is a development based on earlier results, where polyhydroxyalkanoates (PHAs) were produced from the percolate of digested organic household waste. PHAs are polyesters that form the key resource for the production of bioplastics.
Under the pilot, fatty acids are produced directly from organic waste flows. So far, only liquid flows have been used, but now Orga-world can also process dry residual flows, such as domestic, industrial and retail organic waste, to produce bioplastics.
Klaas van den Berg, general manager of Orgaworld, explains: “The process runs on four mini-reactors arranged in parallel that are refreshed alternately, known as a semi-continuous process. In this process, the organic waste is continuously sprayed with hot percolate that increases the bacteria concentrations.
“The bacteria digest the organic waste into sugar, amino acids, fats and other micro-organisms that subsequently will ferment to the desired fatty acids. In the final stage, a different type of bacteria converts the fatty acids into PHAs, which are fully biodegradable plastics. Our aim is to combine the highest possible fatty acids concentration with the highest possible yield of bioplastics from every kilogramme of organic waste.”
The bioplastics market is large and diverse. There are numerous applications in consumer, agricultural and horticultural products as an alternative to regular plastic. It is also used as raw material for chemicals or as an additive to other raw materials, for instance in the production of self-healing concrete.
“Our aim is to combine the highest possible fatty acids concentration with the highest possible yield of bioplastics from every kilo of organic waste.”
Bioplastics are also used for the production of biodegradable plastic bags that are well suited for collecting organic kitchen waste. Eventually, Orgaworld believes these will be returned to its own handling process to close the loop.
Joop Suurmeijer, Orgaworld’s manager of strategic accounts & innovation, says: “We still need a few more years for research and development. Improving the quality of bioplastics requires thorough research and we are partnering with technology developer Paques [on this]. Our aim is to make as many organic residues as possible suitable as a source for the production of basic chemicals within a decade.
“Through the production of bioplastics, we deliver added value to the chemicals industry and we reach one step higher on the value pyramid. The knowledge and expertise that we already possess offer both opportunities and possibilities.”
But is there scope for further development? The Orgaworld hydrolysis container is part of what is called the Lelystad Innovation Center. It involves a dedicated facility where young researchers are given the opportunity to gain practical experience with developments in the field of the circular economy.
Suurmeijer says: “A lot of research is going on in the Netherlands in the field of biopolymers. Orgaworld is closely involved, particularly in the field of organic residual flows, in co-operation with the Delft University of Technology. With our in-house developed technologies and solutions, Orgaworld is a global pioneer in the conversion of organic household waste into bio-based products.
“Our research steadily continues. There is still a long way to go, but we’ve had a good start and are making solid progress.”
The company focuses on all parts of the organic waste processing cycle. Van den Berg explains: “Like the hydrolysis container, we develop, build and manage our own plants and facilities. This means we can focus on improving our processes and use all by-products productively.
“Throughout the years, we have become a versatile and innovative international processors of organic waste materials. Not only are we active in the Netherlands and Canada but, due to our recycling network, we also do business in England and Scotland.
“In addition to processing organic waste, we now also process organic refuse from different types of industries – at our sites as well as their places of business.
“There are few other places in the world where organic waste is as well recycled as it is in the Netherlands. The government obliged municipalities to start sorting waste 20 years ago to reduce its impact on the environment as much as possible.”