The DIGEST-PLAST project’s concept expands problems presented in the implemented POMBIOGAS project entitled ‘Pomeranian Biogas Model’, which was implemented in years 2013-2016 and funded by Polish-Norwegian Research Programme. The project draws attention to the growing problem with the appearance of bioplastics in the surrounding environment.

Municipal waste management in Poland still differs from the EU average, although systematic improvements have been observed in recent years. The visible disproportion in municipal waste treatment methods in the Polish municipal waste management should take place by gradually eliminating the storage of unprocessed waste and at the same time increasing the share of recycling and the share of energy recovery in waste-to-energy plants.

In June 2018 changes in legal acts in the area of environmental protection appeared in the Official Journal of the European Union. The change introduced with the Directive of the European Parliament and of the Council (EU) 2018/851 from May 30, 2018 amended the Directive 2008/98/EC on waste, and introduced obligatory segregation of bio-waste from January 2023. In turn, the Directive of the European Parliament and of the Council 2018/850 from May 30, 2018 amended the Directive 1999/31/EC on waste storage, and introduced the obligation of reduction by 2035 the amount of municipal waste disposal to a maximum of 10% of the total amount of municipal waste generated.

Renewable energy sources (RES) are a key element of the European Commission's long-term strategy, which is set out in an Energy Action Plan to a year 2050 (COM(2011)0885). In November 2016, the Commission published a legislative package entitled 'Clean Energy for all Europeans' (COM (2016) 0860) as part of a wider strategy for the Energy Union (COM (2015) 0080). As agreed in respect to the Plan, the binding EU target RES by the year 2030 should reach 32%, however no mandatory targets have been indicated at a national level.
In June 2019, the government in Poland adopted the amendment to the act on RES, and the European Commission recommended Poland to increase the target share level of energy from RES to at least 25% by the year 2030. EC also recommended to guarantee the full implementation of the target 15% of renewable energy to the year 2020 and to keep it as a baseline from the year 2021.

However, according to the report of the Supreme Audit Office (pol. Najwyższa Izba Kontroli) from 2018, the achievement of the assumed 15% target from renewable sources by the year 2020 may not be achieved.
Due to the entry into force of new provisions on renewable energy sources and at the same time the intensive growth of energy demand, the market for unconventional energy resources in Poland, also based on biomass, is expected to develop in the near future. Summarizing, the following factors are an important premis for the development of waste processing techniques using methane fermentation:

  • the need to increase the share of renewable sources in the overall energy production balance,
  • tightening of environmental standards for the disposal of bioplastic wastes in landfills,
  • enables shift from recovery to recycling (a treatment option which ranks higher on the European waste hierarchy).

Biomass is a natural carbonous resource from origin of living or recently living plant and animal materials. It can be converted to biofuel gases rich in CH4, CO, and H2, through the digestive action of living organisms, during biochemical processes like methane fermentation. Biogas is primarily methane (CH4) and carbon dioxide (CO2). Depending on its origin, it usually contains small amounts ofhydrogen sulphide (H2S), moisture and siloxanes and in the case of landfill gas, also significant amounts of nitrogen.
Results form the research that was carried out during implementation of POM-BIOGAS project, showed that Pomeranian region has a big potential of organic waste available for anaerobic digestion, however in the Pomeranian region, the following obstacles with the greatest impact on the aste management sector were identified:

  • in-effective separate collection of wastes at the source, especially bioplastics wastes,
  • low purity of organic fraction of municipal waste,
  • lack of education and awareness of society about the benefits of waste separate collection
  • system,
  • problem with determination of the actual amount of municipal waste generated.

Additionally, according to the latest studies and observations, the substances harmful to the fermentation process may be delivered to the fermentation reactor together with the substrate, and eventually pose risk to useful bacteria involved in the methane fermentation process. This group not only includes antibiotics, disinfectants, solvents, heavy metals etc., [1-3], but a literature survey suggests that the organic fraction may be also contaminated with ubiquitous and of emerging concern polymers, in particular microplastics [4], both of primary or secondary origin. Recently, bioplastics including biodegradable polymers have been widely introduced to market.

This group of polymers, if not properly treated, may constitute a group of emerging contaminates as well. In response to the growing demand for polymer materials, and at the same time with increasing awareness about sustainable development, new groups of polymer materials appeared, referred to as: ‘plastic from plants’, ‘biodegradable plastic’, ‘oxybiodegradable plastic’ or ‘bioplastic’. Although considered as ecologically friendly and having many advantages, their fate in the environment is still not fully known. In addition, the current method of waste collection does not necessarily and fully allows using their ‘biodegradable properties’, since degradable materials available on the market need special environmental conditions in order to be fully degraded (the right content of oxygen, carbon dioxide, water and microorganisms). Hence, biodegradable polymers might be harmful for the environment, similarly to microplastics. In case of biodegradable polymers, proper collection and separation from the waste stream would be needed otherwise such material may behave as ordinary plastic.

In recent years, polymer packages made of oxybiodegradable plastics, including polymer bags, have been introduced to the market as a solution to the problem of environmental pollution with polymer waste. However, it has been proven that oxybiodegradable plastics simply break down into small pieces, including microplastics, and the whole biodegradation process of these plastics requires a much longer time than the period declared by their producers, thus proper utilization of wastes form oxybiodegradable plastics requires expensive processing.

The proposed scope of the project results from lack of sufficient knowledge related to bioplastics and biodegradable polymers and their susceptibility to methane fermentation processes. Project implementation will provide information on how to impart biodegradable polymers to methane fermentation.
Proposed methane fermentation process for the organic fraction of municipal waste is a promising method for the near future, since it allows reducing the volume of municipal waste disposal by as much as 25-40%, which guarantees partial compliance with the European Union requirements for reducing the stream of organic waste removed to landfills.

The planned activities within the project have a good chance of success thanks to the experience gained during implementation of POM-BIOGAS project and consequent research study that was carried out within the field of methane fermentation and biogas production. Two partners from POM-BIOGAS project – namely Gdansk University of Technology and Norwegian Aquateam COWI have a knowledge and experience within methane fermentation processes, as well as they value and trust each other. Among others, we designed and built a 10 kW micro-biogas plant, which is located in Lubań. Our team is currently implementing COSTAL BIOGAS project, which received funding from the European Regional Development Fund through the Interreg South Baltic Programme and focuses on providing the solutions based on anaerobic digestion anaerobic digestion technology for agricultural waste and marine flora to reduce nutrients in the Baltic Sea.

Additionally, having big Municipal Waste Solid Treatment Plant from Poland as a partner in a project, creates a good opportunity, since the access to the natural resources, especially organics from waste food, will be easy, repeatable and reliable. The research activities foreseen in the project provides a real answer to a current needs which society is facing of, namely: new sources of energy based on bioproducts, proper waste management aiming at circular economy as well as carbon footprint reduction.


[1] K. Kozłowski, J. Dach, A. Lewicki, M. Cieślik, W. Czekała, D. Janczak, Ecological Engineering, 50
(153-160) 2016, DOI: 10.12912/23920629/65490
[2] R. Braun, Biogas – Methangärung organischer Abfallstoffe. Springer Verlag Wien, New York, 1982
[3] M. Kaltschmitt, H. Hartmann, Energie aus Biomasse – Grundlagen, Techniken und Verfahren,
Springer Verlag Berlin, Heidelberg, New York, 2001.
[4] S. Williams, Organic Fertilizers Rife With Microplastics: Study, The Scientist, 2018