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Item type:Publication, Access status: with files , Assessment of methane production, disintegration, and biodegradation potential of bioplastic waste in anaerobic digestion systems(Elsevier, 2024-02); ; ; ; The suitability of bioplastics for treatment in anaerobic digestion and composting plants is not always clear despite their increasing popularity as an alternative to oil-based polymers. This study aims to estimate the anaerobic degradation of various combinations of bioplastics (cellulose acetate, polylactic acid (PLA) and polybutylene succinate (PBS)), filler (organic – gelatine – and inorganic) and plasticizer (triacetin) combinations, under conventional industrial digestion conditions. The investigation encompasses the evaluation of both physical (disintegration) and biological degradation processes, along with the modelling of their methane production utilizing various iterations of the Gompertz-type model. Results indicate that, during typical industrial residence time, cellulose-based bioplastics exhibit high methane yield (approximately 500 NmlCH4/gVS) and near-complete degradation (both physical and biological), while PLA has minimal biodegradation (11%) and low methane yield (59 NmlCH4/gVS). PBS-gelatine blends generate a significant amount of methane early in the digestion process (174 and 116 NmlCH4/gVS for flakes and pieces, respectively) but do not achieve full degradation. These findings suggest that the effectiveness of bioplastics degradation varies based on their composition, and further research is needed to optimize their treatment in common industrial facilities.Publicationtype: Journal Article56 141 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Degradation of thermoplastic cellulose acetate-based bioplastics by full-scale experimentation of industrial anaerobic digestion and composting(2023-04-15); ; ; ; The ability of full-scale industrial plants to degrade bioplastics waste must be verified to exclude any negative effects on the quality of the process outputs. This study aims to assess the degradation of two thermoplastic cellulose acetate-based bioplastics, in pure and composite forms in both Anaerobic Digestion (AD) and Composting (C) industrial conditions. The main degradation occurred during AD, where a disintegration of about 36% and 50% was achieved from pure and composite thermoplastic cellulose acetate, respectively. The disintegration during C did not exceed 20% for both samples. The combined process resulted in a slightly higher degradation (58–40%) than that obtained in AD, revealing how the main alteration of samples occurred in an anaerobic environment. Despite this macroscopic degradation, the samples showed only minor superficial degradation as highlighted from SEM analysis. FT-IR spectroscopy, TGA andDSC analyses showed that the biodegradation mechanism involved mainly the plasticizer loss and deacetylation of the cellulose matrix, with only partial degradation of cellulose backbone However, both deacetylation and degradation were favored in AD and AD + C processes and from the presence of filler in anaerobic conditions. These results demonstrated how the degradation obtained on an industrial scale can differ significantly from those obtained in the laboratory scale, especially for pure thermoplastic cellulose acetate. Furthermore, current industrial AD and C process resulted not optimized for the treatment of thermoplastic cellulose acetate-based bioplastics. Hence, this works could help waste facilities managers to process emerging materials such as bioplastics in a more sustainable way.Publicationtype: Journal Article43 26 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Co-digestion of food waste and cellulose-based bioplastic: From batch to semi-continuous scale investigation(2023-02-01); ; ; ; Only few studies on the behaviour of bioplastics in anaerobic co-digestion could be found in literature and most of them are conducted in batch mode. Despite the fact that continuous experiments confirm or add new insight to the findings acquired from batch ones, there is still lack of such studies. This work aims to cover this gap, carrying out a semi-continuous anaerobic co-digestion of food waste and cellulose acetate (which its behaviour under anaerobic environment is also quite unexplored). After a first evaluation of the potential methane production from each substrate at batch scale, the semi-continuous co-digestion of food waste and cellulose acetate was carried out in three configurations. During the semi-continuous process, a methane yield of 331 NmlCH4/gVS was generated from the co-digestion of food waste and cellulose acetate while bioplastics specimens achieved a weight loss of about 45 %. The results were both lower than the one obtained from batch co-digestion, although methane production rates were comparable regardless of being fed with or without bioplastics. An increase was registered after 65 days of semi-continuous process, due to the accumulation of CA specimens. This confirms the different degradation trends between bioplastics and food waste.Publicationtype: Journal Article55 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Energy recovery options for the management of cellulose-based bio-plastics and mixed municipal solid wasteThe incomplete degradation of bio-plastics waste is undermining the suitability of current anaerobic digestion (AD) and composting, opening up the exploration of new treatment routes, including mixed waste. Bio-plastics are treated with mixed waste in a mechanical-biological treatment (MBT) plant with the production of a dry fraction for incineration and a biologically stable one for landfill. An alternative post-treatment of the bio-stabilised waste based on AD is possible. It follows that the main goal of this study is to verify the feasibility of managing cellulose-based bio-plastics with mixed municipal waste, comparing the AD of the MBT plant outputs with the possible solution of incineration. Experimental lab tests have been carried out to describe the two processes, whose results were the basis for an economic analysis. The values of biochemical methane potential (BMP) and higher heating value (HHV) are used as an index for AD and incineration, respectively. Samples with and without bio-plastics were created; fresh and processed (7 and 14 days of biostabilization) samples were, thus, analysed. For AD, the fresh waste averaged 177 NmL CH4/gVS and a 22% and 33% decrease in BMP value was achieved after 7 and 14 days of biostabilization, respectively. Samples with and without bio-plastics revealed a similar trend. 7 and 14 days of biostabilization increased the HHV of fresh waste (18.01 J/kg) of 16.1% and 19.7%, respectively. Bio-plastics did not significantly change the HHV. The economic analysis revealed the suitability of both AD and incineration, irrespective of the presence of bioplastics.Publicationtype: Journal Article42 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Effects of cellulose-based bio-plastics on the aerobic biological stabilization treatment of mixed municipal solid waste: A lab-scale assessment(2022-09-15); ; ; ; The aim of this work is to assess how the presence of cellulose-based bio-plastics influence the biological stabilization of mixed Municipal Solid Waste (MSW). For the scope, two cellulose acetate bio-plastics have been mixed with a synthetic mixed waste to create samples with and without bio-plastics. A self-induced biostabilization has been carried out for 7 and 14 days where temperature and off-gas have been monitored continuously. Results about temperature evolution, O2 consumption, CO2 production and respiratory quotient did not show a substantial difference regarding both the duration of the process and the presence of cellulose-based bio-plastics on the mixture. On the average, the temperature peak and the maximum daily O2 consumption and CO2 production were 52.2 °C, 35.81 g O2/kg DM *d and 48.95 g CO2/kg DM *d respectively. Disintegration of bio-plastics samples after 7 and 14 days were comparable (on the average 23.13%). The self-induced biostabilization gave its main contribution after 4 days and resulted almost finished at the end of the day 7 of the process. Results showed that cellulose-based bio-plastics did not give a negative effect on mixed MSW biological stabilization and suggest a possible management, aiming at energy recovery of the outputs.Publicationtype: Journal ArticleScopus© Citations 8 38 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The influence of bio-plastics for food packaging on combined anaerobic digestion and composting treatment of organic municipal waste(2022-05-01); ; ; ; The use of bio-plastic-based packaging as an alternative to conventional plastic packaging is increasing. Among the plethora of different bio-based plastics, the most relevant ones are those that, at the end of their life, can be treated with the organic fraction of municipal solid waste. Even in these cases, their impact on the waste processing and recycling is not always positive. This study aim to assess on a laboratory scale the influence on combined anaerobic digestion and composting industrial processes of a bio-based plastic film, namely cellulose acetate (CA), in pure and modified (additions of additive) forms. CA films were mixed with organic waste and subjected to: (i) anaerobic digestion; (ii) active composting and (iii) two stages of curing composting. Anaerobic digestion and composting were monitored through methane yield and oxygen uptake respectively; additionally, the bio-plastics degree of disintegration was assessed during all the processes. The final disintegration of pure and modified CA was 73.82% and 54.66%, respectively. Anaerobic digestion contributes to the disintegration of the material, while aerobic treatment appears to be nearly ineffective, especially for modified CA. The presence of cellulose acetate during anaerobic digestion of food waste increased the methane yield by about 4.5%. Bioassay confirmed the absence of possible toxic effects on the final compost from the bio-plastic treatment. Although bio-based materials are not the only solution to plastic pollution, the findings confirm the need to upgrade the organic waste treatment plants and the necessity to revise the requirements for the use of compost in agriculture.Publicationtype: Journal Article58 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Biochemical methane potential assessment of municipal solid waste generated in Asian cities: A case study of Karachi, PakistanMunicipal solid waste (MSW) generation rate in Asian cities is exponentially increasing with rise in urbanization and commercial activities. Beside this, the cities in developing Asia are deficient in adequate waste management and facing energy shortage as well. The ineffectual waste management practice is one of the main causative factors behind the negative repercussions on public health and environment. This paper provides an estimation of power generation potential along with economic and environmental benefits of biochemical methane production from MSW. The biochemical methane potential (BMP) test of the MSW generated in Karachi, Pakistan was conducted by using the fresh synthetic waste sample. Through the analysis of the results obtained in this study and available data of the MSW generation (quantity, organic fraction and moisture content) in Karachi it is estimated that, every year about 5600 tons of methane are being wasted to atmosphere adding enormous share in global climate change. This study estimated that, about 63 MWe electric power can be generated by establishing biowaste digestion plants with power generation facilities in the city. The generated power can contribute 2.1% share in daily power supply and 21% power shortage can be reduced as well. Additionally, about 401.3 million-PKRs (2.6 million-US) revenue can be earned every year by selling the power generated by utilizing the MSW in waste to energy plants. Moreover, 0.13 Mt CO2-eq/annum greenhouse effect caused by methane emissions from open disposal of MSW can be eliminated.Publicationtype: Journal Article165 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Development of a method to produce standardised and storable inocula for biomethane potential tests – Preliminary stepsIn biomethane potential (BMP) tests, different sources and origins of inocula might cause significant variations in the tests’ results, preventing from acquiring a harmonised and standardised evaluation of the different substrates. In this study, a method to produce standardised and storable inocula was elaborated. For the development of the different investigation steps a control sludge originated from a wastewater treatment plant was utilised. Freeze-drying was applied in the framework of this study as a long-term conservation method for the anaerobic inocula. In order to ensure a closed system with anaerobic conditions at all times, a test system was developed to allow accurate and representative mass-balance experiments. The test results demonstrated that inocula conservation and re-suspension in BMP tests is possible; the limit value of the expected methane yield of a positive and lyophilised reference-control, was reached. However, a lag phase of 7–10 days was obtained, possibly due to the damage of microorganisms as a consequence of the conservation process. Further investigations need to be carried out to optimise the conservation process of the produced inocula or an initial preparation phase should be considered to reduce the lag phase.Publicationtype: Journal Article231 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Development of a method to produce standardised and storable inocula for biomethane potential testsPublicationtype: Conference Paper39 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Development of a method to produce standardized and storable inocula for biomethane potential testsPublicationtype: Conference Paper31