Examinando por Autor "Martin-Gamboa, Mario"

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Environmental life cycle assessment of polyhydroxyalkanoates production by purple phototrophic bacteria mixed cultures
(Elsevier, 2023) Martin-Gamboa, Mario; Allegue, Luis D.; Puyol, Daniel; Melero, Juan Antonio; Dufour, Javier
Bioplastics offer a promising sustainable alternative to petroleum-based plastics due to their biodegradability as well as favourable thermal and mechanical properties. Among different types of biobased polymers, the production of polyhydroxyalkanoates (PHA) using purple phototrophic bacteria (PPB) and low-value substrates has gained increasing interest. Despite the momentum, challenges regarding the scalability and environmental feasibility of this biopolymer production pathway remain. In response, this study employs an exploratory LCA approach to quantitatively assesses the potential environmental implications of PHA production in powder form and the joint management of the organic fraction of municipal solid waste (OFMSW) through a novel photobiorefinery system that uses PPB mixed cultures. Environmental impacts were tested under multiple improvement scenarios and benchmarked against the production of conventional fossil-based granulate or unprocessed plastics, including low density polyethylene (LDPE), polyethylene terephthalate (PET) and polyurethane (PU). The photobiorefinery stage was found to have the greatest contribution to the impact categories, particularly due to direct emissions, consumption of electricity and production of extractive chemical agents used. These factors accounted for over 70% of the photobiorefinery impact in all cases. Avoided impacts provided net favourable outcomes in terms of carbon footprint and fossil resources when comparing PHA production to conventional plastics, especially PET and PU, with impact reductions ranging from 30% to 60%, respectively. However, when considering other impact categories like eutrophication, this situation was less favourable. The exploration of alternative scenarios offered significant impact reductions, especially when renewable electricity or an environmentally friendly extraction agent is used. Moreover, minimizing methane losses or co-producing hydrogen in the photobiorefinery had a notably positive effect on the carbon footprint, reducing the impact by more than 2 t of CO2 eq per t of PHA powder compared to the base case. Therefore, the implementation of feasible improvement measures in the short term can position PHA produced by mixed cultures as a sustainable alternative to petroleum-based plastics.
Environmental life cycle assessment of the incorporation of recycled high-density polyethylene to polyethylene pipe grade resins
(Elsevier, 2021) Istrate, Ioan-Robert; Rafael Juan; Martin-Gamboa, Mario; Domínguez, Carlos; García-Muñoz, Rafael A.; Dufour, Javier
Plastic recycling involves a range of potential environmental benefits, from curbing landfill and incineration rates to the reduction of greenhouse gas emissions. However, the main challenge is to find applications where recycled plastic can successfully provide the same functionality as the replaced virgin plastic. Particularly, the incorporation of recycled high-density polyethylene (HDPE) to polyethylene (PE) pipe grade resins is a great challenge that is not currently being implemented in the manufacture of pressure pipes. In this study, life cycle assessment (LCA) is applied to quantitatively evaluate the potential environmental impacts from producing PE pipe grade resins from recycled HDPE blended with virgin HDPE. The LCA involves four HDPE waste feedstocks (crates/caps, packaging/detergency bottles, post-consumer industrial containers, and automobile fuel tanks) and two PE pipe grades (PE80 and PE100). Moreover, different allocation approaches that affect the LCA of plastic recycling, namely the cut-off approach and the Circular Footprint Formula, were investigated. The recycled content was found to largely determine the LCA results. In this regard, the production of PE80 quality from the pure HDPE waste feedstocks (such as automobile fuel tanks and post-consumer industrial containers) allows a higher recycled content, thus resulting in lower impacts. Compared with a 100 % virgin resin, these two sce- narios show 80 % and 53 % less carbon footprint if the waste feedstock is considered burdens free (cut-off allocation). These percentages however decrease to 32 % and 20 % if the impacts and benefits are shared ac- cording to the Circular Footprint Formula. These trends were similarly observed for most of the impact categories evaluated, such as, acidification and fossil resources. The robustness of these results is supported by error propagation via Monte Carlo simulation.