an official journal of: published by:
an official journal of: published by:
Editor in Chief: RAFFAELLO COSSU


  • Filippo Marchelli - Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Italy
  • Roberta Ferrentino - Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Italy
  • Giulia Ischia - Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Italy
  • Marco Calvi - Certottica S.c.r.l., Italian Institute of Certification of Optical Products, Italy
  • Gianni Andreottola - Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Italy
  • Luca Fiori - Department of Civil, Environmental and Mechanical Engineering (DICAM), University of Trento, Italy

Released under CC BY-NC-ND

Copyright: © 2023 CISA Publisher


Bioplastics are increasingly replacing traditional plastics in many sectors, but the legislative and operative frameworks for their disposal remain unclear: they should be collected and treated together with the organic fraction of municipal solid waste (OFMSW), but often do not biodegrade satisfactorily in the plants that treat OFMSW. This work focuses on a type of cellulose diacetate employed in the eyewear industry to analyse hydrothermal carbonization (HTC) as a pre-treatment before anaerobic digestion (AD). The results show that HTC can hydrolyse this bioplastic even at moderate temperatures, reaching an almost total dissolution in the liquid phase at 210 °C and, at higher temperatures, producing hydrochar. When the HTC slurry obtained at 210 °C is fed to mesophilic or thermophilic AD, both the amount and the production rate of biogas are enhanced compared to the raw bioplastic. In particular, in thermophilic conditions, the amount of produced biogas undergoes at least a threefold increase compared to the untreated cellulose diacetate. Thus, this work confirms that a prior HTC step may be a suitable approach to enhance the disposal and energy recovery of bioplastics through AD.


Editorial History

  • Received: 14 Mar 2023
  • Revised: 30 May 2023
  • Accepted: 15 Jun 2023
  • Available online: 30 Jun 2023


APHA, AWWA, & WEF. (2012). Standard methods for the examination of water and wastewater. In American Public Health Association (21st ed.)

Athanassiou, A. (2021). Si fa presto a dire bioplastiche non illudiamoci: dovremo investire nel loro smaltimento.

Bandini, F., Vaccari, F., Soldano, M., Piccinini, S., Misci, C., Bellotti, G., Taskin, E., Cocconcelli, P. S., & Puglisi, E. (2022). Rigid bioplastics shape the microbial communities involved in the treatment of the organic fraction of municipal solid waste. Frontiers in Microbiology, 13, 4410.
DOI 10.3389/fmicb.2022.1035561

Battista, F., Frison, N., & Bolzonella, D. (2021). Can bioplastics be treated in conventional anaerobic digesters for food waste treatment? Environmental Technology & Innovation, 22, 101393.
DOI 10.1016/J.ETI.2021.101393

Beniche, I., El Bari, H., Siles, J. A., Chica, A. F., & Martín, M. Á. (2021). Methane production by anaerobic co-digestion of mixed agricultural waste: cabbage and cauliflower. Environmental Technology, 42(28), 4550–4558.
DOI 10.1080/09593330.2020.1770341

Bona, D., Scrinzi, D., Tonon, G., Ventura, M., Nardin, T., Zottele, F., Andreis, D., Andreottola, G., Fiori, L., & Silvestri, S. (2022). Hydrochar and hydrochar co-compost from OFMSW digestate for soil application: 2. agro-environmental properties. Journal of Environmental Management, 312, 114894.
DOI 10.1016/j.jenvman.2022.114894

Calabro’, P. S., Folino, A., Fazzino, F., & Komilis, D. (2020). Preliminary evaluation of the anaerobic biodegradability of three biobased materials used for the production of disposable plastics. Journal of Hazardous Materials, 390, 121653.
DOI 10.1016/j.jhazmat.2019.121653

Carollo, P., & Grospietro, B. (2004). 5.5 Plastic materials. Macromolecular Symposia, 208(1), 335–352.
DOI 10.1002/masy.200450414

Cazaudehore, G., Guyoneaud, R., Lallement, A., Souquet, P., Gassie, C., Sambusiti, C., Grassl, B., Jiménez-Lamana, J., Cauzzi, P., & Monlau, F. (2023). Simulation of biowastes and biodegradable plastics co-digestion in semi-continuous reactors: Performances and agronomic evaluation. Bioresource Technology, 369, 128313.
DOI 10.1016/J.BIORTECH.2022.128313

Ferrentino, R., Merzari, F., Fiori, L., & Andreottola, G. (2020). Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production. Energies, 13(23), 6262.
DOI 10.3390/en13236262

Fiori, L., Basso, D., Castello, D., & Baratieri, M. (2014). Hydrothermal carbonization of biomass: Design of a batch reactor and preliminary experimental results. Chemical Engineering Transactions, 37, 55–60.
DOI 10.3303/CET1437010

Folino, A., Pangallo, D., & Calabrò, P. S. (2023). Assessing bioplastics biodegradability by standard and research methods: Current trends and open issues. Journal of Environmental Chemical Engineering, 11(2), 109424.
DOI 10.1016/J.JECE.2023.109424

Gadaleta, G., Ferrara, C., De Gisi, S., Notarnicola, M., & De Feo, G. (2023). Life cycle assessment of end-of-life options for cellulose-based bioplastics when introduced into a municipal solid waste management system. Science of The Total Environment, 871, 161958.
DOI 10.1016/J.SCITOTENV.2023.161958

Gilbert, M. (2017). Cellulose Plastics. In Brydson’s Plastics Materials (pp. 617–630). Elsevier.
DOI 10.1016/B978-0-323-35824-8.00022-0

Gómez, E. F., & Michel, F. C. (2013). Biodegradability of conventional and bio-based plastics and natural fiber composites during composting, anaerobic digestion and long-term soil incubation. Polymer Degradation and Stability, 98(12), 2583–2591.
DOI 10.1016/j.polymdegradstab.2013.09.018

González, R., Ellacuriaga, M., Aguilar-Pesantes, A., Carrillo-Peña, D., García-Cascallana, J., Smith, R., & Gómez, X. (2021). Feasibility of Coupling Anaerobic Digestion and Hydrothermal Carbonization: Analyzing Thermal Demand. Applied Sciences, 11(24), 11660.
DOI 10.3390/app112411660

Hansraj, R., Govender, B., Joosab, M., Magubane, S., Rawat, Z., & Bissessur, A. (2021). Spectacle frames: Disposal practices, biodegradability and biocompatibility – A pilot study. African Vision and Eye Health, 80(1).
DOI 10.4102/aveh.v80i1.621

il Dolomiti. (2019). Bioplastica e “‘Plastic tax’”, tanti si oppongono (anche i gestori dei biodigestori) ma c’è altra via? L’Ue va in quella direzione e l’Italia è tra i maggiori produttori di plastica.

Il Tirreno Empoli. (2019). Alia conferma: bioplastica non riciclabile Presto un tavolo per risolvere il problema.

Ischia, G., Cutillo, M., Guella, G., Bazzanella, N., Cazzanelli, M., Orlandi, M., Miotello, A., & Fiori, L. (2022). Hydrothermal carbonization of glucose : Secondary char properties , reaction pathways , and kinetics. Chemical Engineering Journal, 449(June), 137827.
DOI 10.1016/j.cej.2022.137827

Ischia, G., & Fiori, L. (2021). Hydrothermal Carbonization of Organic Waste and Biomass: A Review on Process, Reactor, and Plant Modeling. Waste and Biomass Valorization, 12(6), 2797–2824.
DOI 10.1007/s12649-020-01255-3

Kabasci, S. (2020). Biobased plastics. In Plastic Waste and Recycling (pp. 67–96). Elsevier.
DOI 10.1016/B978-0-12-817880-5.00004-9

Karan, H., Funk, C., Grabert, M., Oey, M., & Hankamer, B. (2019). Green Bioplastics as Part of a Circular Bioeconomy. Trends in Plant Science, 24(3), 237–249.
DOI 10.1016/j.tplants.2018.11.010

Kosheleva, A., Gadaleta, G., De Gisi, S., Heerenklage, J., Picuno, C., Notarnicola, M., Kuchta, K., & Sorrentino, A. (2023). Co-digestion of food waste and cellulose-based bioplastic: From batch to semi-continuous scale investigation. Waste Management, 156, 272–281.
DOI 10.1016/J.WASMAN.2022.11.031

Lynam, J. G., Coronella, C. J., Yan, W., Reza, M. T., & Vasquez, V. R. (2011). Acetic acid and lithium chloride effects on hydrothermal carbonization of lignocellulosic biomass. Bioresource Technology, 102(10), 6192–6199.
DOI 10.1016/j.biortech.2011.02.035

Masoumi, S., Borugadda, V. B., Nanda, S., & Dalai, A. K. (2021). Hydrochar: A Review on Its Production Technologies and Applications. Catalysts, 11(8), 939.
DOI 10.3390/catal11080939

Mumtaz, H., Sobek, S., Werle, S., Sajdak, M., & Muzyka, R. (2023). Hydrothermal treatment of plastic waste within a circular economy perspective. Sustainable Chemistry and Pharmacy, 32, 100991.
DOI 10.1016/J.SCP.2023.100991

Nandakumar, A., Chuah, J.-A., & Sudesh, K. (2021). Bioplastics: A boon or bane? Renewable and Sustainable Energy Reviews, 147, 111237.
DOI 10.1016/j.rser.2021.111237

Puechner, P., Mueller, W. R., & Bardtke, D. (1995). Assessing the biodegradation potential of polymers in screening- and long-term test systems. Journal of Environmental Polymer Degradation, 3(3), 133–143.
DOI 10.1007/BF02068464/METRICS

Puls, J., Wilson, S. A., & Hölter, D. (2011). Degradation of Cellulose Acetate-Based Materials: A Review. Journal of Polymers and the Environment, 19(1), 152–165.
DOI 10.1007/S10924-010-0258-0/FIGURES/11

Purnomo, C., Castello, D., & Fiori, L. (2018). Granular Activated Carbon from Grape Seeds Hydrothermal Char. Applied Sciences, 8(3), 331.
DOI 10.3390/app8030331

RameshKumar, S., Shaiju, P., O’Connor, K. E., & P, R. B. (2020). Bio-based and biodegradable polymers - State-of-the-art, challenges and emerging trends. Current Opinion in Green and Sustainable Chemistry, 21, 75–81.
DOI 10.1016/j.cogsc.2019.12.005

Scrinzi, D., Bona, D., Denaro, A., Silvestri, S., Andreottola, G., & Fiori, L. (2022). Hydrochar and hydrochar co-compost from OFMSW digestate for soil application: 1. production and chemical characterization. Journal of Environmental Management, 309, 114688.
DOI 10.1016/j.jenvman.2022.114688

Shin, P. K., Kim, M. H., & Kim, J. M. (1997). Biodegradability of degradable plastics exposed to anaerobic digested sludge and simulated landfill conditions. Journal of Environmental Polymer Degradation 1997 5:1, 5(1), 33–39.
DOI 10.1007/BF02763566

Thakur, S., Chaudhary, J., Sharma, B., Verma, A., Tamulevicius, S., & Thakur, V. K. (2018). Sustainability of bioplastics: Opportunities and challenges. Current Opinion in Green and Sustainable Chemistry, 13, 68–75.
DOI 10.1016/j.cogsc.2018.04.013

Vardar, S., Demirel, B., & Onay, T. T. (2022). Degradability of bioplastics in anaerobic digestion systems and their effects on biogas production: a review. Reviews in Environmental Science and Biotechnology, 21(1), 205–223.
DOI 10.1007/S11157-021-09610-Z/FIGURES/2

Volpe, M., Messineo, A., Mäkelä, M., Barr, M. R., Volpe, R., Corrado, C., & Fiori, L. (2020). Reactivity of cellulose during hydrothermal carbonization of lignocellulosic biomass. Fuel Processing Technology, 206, 106456.
DOI 10.1016/j.fuproc.2020.106456

Yadav, N., & Hakkarainen, M. (2021). Degradable or not? Cellulose acetate as a model for complicated interplay between structure, environment and degradation. Chemosphere, 265, 128731.
DOI 10.1016/j.chemosphere.2020.128731

Yagi, H., Ninomiya, F., Funabashi, M., & Kunioka, M. (2009). Anaerobic Biodegradation Tests of Poly(lactic acid) under Mesophilic and Thermophilic Conditions Using a New Evaluation System for Methane Fermentation in Anaerobic Sludge. International Journal of Molecular Sciences, 10(9), 3824–3835.
DOI 10.3390/ijms10093824

Yu, C., Dongsu, B., Tao, Z., Xintong, J., Ming, C., Siqi, W., Zheng, S., & Yalei, Z. (2023). Anaerobic co-digestion of three commercial bio-plastic bags with food waste: Effects on methane production and microbial community structure. Science of The Total Environment, 859, 159967.
DOI 10.1016/J.SCITOTENV.2022.159967