Organic recycling of post-consumer /industrial bio-based plastics through industrial aerobic composting and anaerobic digestion - Techno-economic sustainability criteria and indicators

Degradation and environmental assessment of compostable packaging mixed with biowaste in full-scale industrial composting conditions

The incorporation of representative commercial compostable materials into a full-scale open-air windrow composting process in an industrial site using household-separated biowaste was investigated. Two batches out of the same initial biowaste mixture were studied, one as control and the other containing initially 1.28 wt% of certified compostable plastics. No significant differences in the composting process were revealed. Compostable plastics exhibited a 98 wt% mass loss after 4 months, aligning with industrial composting times. The evolution of the morphology of the materials unveiled polymer specific degradation mechanisms. Both Safety requirements for organic farming were met. Ecotoxicity tests showed no adverse effects, agronomic fertilizing and amending quality was high, the materials compost even enhancing barley growth. The ecological impact assessment demonstrated an advantage for composting over incineration for seven of the eight indicators. In conclusion, this study shows the successful integration of compostable materials into industrial composting, upholding product safety and quality.

Biodegradation of plastics in the pelagic environment of the coastal zone - Proposed test method under controlled laboratory conditions

The increasing quantities of plastic litter accumulated in the oceans, including microplastics, represent a serious environmental threat. Despite the recent legislative actions, the plastic littering problem will not disappear in a short time. It may, however be ameliorated by replacing conventional non-degradable plastics with bio-based materials biodegradable in marine environment (targeting the non-recycled or mismanaged plastic waste). Although priority is set to prevention of plastic litter by means of the circular economy principles, biodegradability is a means of controlling unintentional plastic pollution. In this effort, the development of reliable test methods that would be used along with standard specifications for determining the biodegradability of novel polymeric materials or plastics in marine environments, is a necessary complementary component of the whole strategy to control the marine plastic litter and micro-, nano-plastics threat. The present work focuses on identifying gaps and improving available laboratory test methods for measuring the aerobic biodegradation of plastics in the seawater column within the coastal zone (pelagic environment). The research work followed a methodology that is based on recommendations of ASTM D6691:2017 concerning biodegradation of plastics in the seawater and the similar ISO 23977-1:2020. Three different implementation schemes of the test method were applied using different experimental setups and measuring techniques for monitoring the evolved CO2. The effect of critical parameters affecting nutrient adequacy (concentration in inoculum) and oxygen adequacy (bioreactor size, sample size, frequency of aeration) on the biodegradation of four tested materials was explored, and optimal values are proposed. The results allowed for the refinement of the proposed test method to improve reliability and reproducibility.

The development of recycling methods for bio-based materials - A challenge in the implementation of a circular economy: A review

This review focuses on the characteristics of the most widely used biopolymers that contain starch, polylactic acid, cellulose and/or polybutylene succinate. Because worldwide production of bio-based materials has grown dynamically, their waste is increasingly found in the existing waste treatment plants. The development of recycling methods for bio-based materials remains a challenge in the implementation of a circular economy. This article summarizes the recycling methods for bio-based materials, which, in the hierarchy of waste management, is much more desirable than landfilling. Several methods of recycling are available for the end-of-life management of bio-based products, which include mechanical (reuse of waste as a valuable raw material for further processing), chemical (feedstock recycling) and organic (anaerobic digestion or composting) ones. The use of chemical or mechanical recycling is less favourable, more costly and requires the improvement of systems for separation of bio-based materials from the rest of the waste stream. Organic recycling can be a sustainable alternative to those two methods. In organic recycling, bio-based materials can be biologically treated under aerobic or anaerobic conditions, depending on the characteristics of the materials. The choice of the recycling method to be implemented depends on the economic situation and on the properties of the bio-based products and their susceptibility to degradation. Thus, it is necessary to label the products to indicate which method of recycling is most appropriate.

Bio-Based Plastics Production, Impact and End of Life: A Literature Review and Content Analysis

The accumulation of plastic wastes is one of the most widely spread problems affecting the environment. The reality that plastics can be made from renewable resources and degrade naturally has prompted academics to think outside the box to develop “better for the environment” items. In this paper, a bibliometric analysis of the scholarly publications related to bio-based plastics within the last 20 years is presented. Annual progression, geographic and research area distribution, and keyword co-occurrence were all examined. Six distinct clusters emerged from keyword analysis, which were further categorized into three directions: production to marketing; impact on the environment, economy, and society; and end-of-life (EoL) options. The major focus was on how to counter the weaknesses and challenges of bio-based plastics and take opportunities using the inherent advantages of bio-based plastics. Comprehensive studies regarding the impact of bio-based plastics on the environment, economy and social sustainability are still deficient. Although there are many promising innovations in this area, most of them are at the research stage. The benefits of bio-based plastics and better EoL options can be enjoyed only after increased production.

Plastic waste recycling: existing Indian scenario and future opportunities

This review article aims to suggest recycling technological options in India and illustrates plastic recycling clusters and reprocessing infrastructure for plastic waste (PW) recycling in India. The study shows that a majority of states in India are engaged in recycling, road construction, and co-processing in cement kilns while reprocessing capabilities among the reprocessors are highest for polypropylene (PP) and polyethylene (PE) polymer materials. This review suggests that there are key opportunities for mechanical recycling, chemical recycling, waste-to-energy approaches, and bio-based polymers as an alternative to deliver impact to India's PW problem. On the other hand, overall, polyurethane, nylon, and polyethylene terephthalate appear most competitive for chemical recycling. Compared to conventional fossil fuel energy sources, polyethylene (PE), polypropylene (PP), and polystyrene are the three main polymers with higher calorific values suitable for energy production. Also, multi-sensor-based artificial intelligence and blockchain technology and digitization for PW recycling can prove to be the future for India in the waste flow chain and its management. Overall, for a circular plastic economy in India, there is a necessity for a technology-enabled accountable quality-assured collaborative supply chain of virgin and recycled material.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13762-022-04079-x.

Rosmarinic Acid and Ulvan from Terrestrial and Marine Sources in Anti-Microbial Bionanosystems and Biomaterials

In order to increase their sustainability, antimicrobial renewable molecules are fundamental additions to consumer goods. Rosmarinic acid is extracted from several terrestrial plants and represents an effective anti-microbial agent. Ulvan, extracted from algae, is an anti-microbial polysaccharide. The present review is dedicated to discussing the sources and the extraction methodologies for obtaining rosmarinic acid and ulvan. Moreover, the preparation of bioanosystems, integrating the two molecules with organic or inorganic substrates, are reviewed as methodologies to increase their effectiveness and stability. Finally, the possibility of preparing functional biomaterials and anti-microbial final products is discussed, considering scientific literature. The performed analysis indicated that the production of both molecules is not yet performed with mature industrial technologies. Nevertheless, both molecules could potentially be used in the packaging, biomedical, pharmaceutical, cosmetic, sanitary and personal care sectors, despite some research being required for developing functional materials with specific properties to pave the way for many more applications.

The Critical Importance of Adopting Whole-of-Life Strategies for Polymers and Plastics

Plastics have been revolutionary in numerous sectors, and many of the positive attributes of modern life can be attributed to their use. However, plastics are often treated only as disposable commodities, which has led to the ever-increasing accumulation of plastic and plastic by-products in the environment as waste, and an unacceptable growth of microplastic and nanoplastic pollution. The catchphrase “plastics are everywhere”, perhaps once seen as extolling the virtues of plastics, is now seen by most as a potential or actual threat. Scientists are confronting this environmental crisis, both by developing recycling methods to deal with the legacy of plastic waste, and by highlighting the need to develop and implement effective whole-of-life strategies in the future use of plastic materials. The importance and topicality of this subject are evidenced by the dramatic increase in the use of terms such as “whole of life”, “life-cycle assessment”, “circular economy” and “sustainable polymers” in the scientific and broader literature. Effective solutions, however, are still to be forthcoming. In this review, we assess the potential for implementing whole-of-life strategies for plastics to achieve our vision of a circular economy. In this context, we consider the ways in which given plastics might be recycled into the same plastic for potential use in the same application, with minimal material loss, the lowest energy cost, and the least potential for polluting the environment.