Athanasios Fountoulakis, "Biodegradation study of bioplastics using activated sludge", Diploma Work, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece, 2022
https://doi.org/10.26233/heallink.tuc.93702
Plastic has been fully integrated into human daily life and is now an integral part of modern life. However, despite its advantages, it is responsible for a large number of environmental problems such as marine and terrestrial pollution that adversely affect living organisms and human health while at the same time causing a multitude of direct and indirect ecological, social and economic problems. To avoid these problems the world community has turned to the use of bioplastics a term that refers to biodegradable plastics, or they may not be degradable, but produced from organic materials or renewable raw materials, such as starch, cellulose, vegetable oils and vegetable fats. However, their reckless use and disposal has led to new problems, similar to those of plastics.The purpose of this thesis is to investigate the ability of activated sludge microorganisms from the sewage treatment plant of the Municipality of Platanias to biodegrade the bioplastics PLA (polylactic acid) and PHB (poly-3-hydroxybutanoic ester). More specifically, the experiment lasted about 3 months (95 days) on a laboratory scale where the samples were put in constant agitation. The measurements that followed mainly concern the pellets of each kind and the creation of biofilms on their surface and the counting of microplastics in the activated sludge. Weight measurements, total reflectance infrared spectroscopy, microscopy, and measurements of biofilm-related cells and proteins were performed.Overall, poly-3-hydroxybutanoate (PHB) pellets showed weight reduction and biofilm development on their surface in contrast to polylactic acid (PLA) which did not show significant differences.