Baseline Data of Low-Density Polyethylene Continuous Pyrolysis for Liquid Fuel Manufacture

The recycling of end-of-life plastics is a problem, since small parts can be returned into circulation. The rest is burned, landfilled or recycled into low-quality heating oil by pyrolysis methods. The disadvantages of this method are the need to dispose the formed by-product, pyrolytic carbon, the poor quality of produced liquid fuel and the low productivity of the method associated with the periodicity of the process. In this work, methods of thermogravimetry and chromatography–mass spectrometry (GC-MS) have been used to study the co-pyrolysis products of low-density polyethylene (LDPE) and oxygen-containing substances at the pressures of 4–8 MPa and temperatures of 520–620 °C. Experiments have highlighted the conditions needed for producing of high-quality liquid fuel. Initial data have been prepared for the design of a continuous pyrolysis reactor to dispose polymer waste for the production of bio-oil which would be available to enter the petrochemical products market.

An Empirical Study on the Main Determinants of Recycling Plastic Waste in Tunisia

Over the past fifteen years, numerous policies for recycling and recovering waste have been implemented throughout the world. Tunisia is among the countries considering recycling as a sustainable development path. This empirical study aimed to investigate and examine the influence of financial determinants measured by the price of waste disposal (PDI), institutional determinants measured by the collection of waste (CW) and the number of drop-off recycling centers, and ordinance and demographic determinants measured by the population density and the recycling rate for plastic as a domestic waste based on a panel of 24 Tunisian governorates over the 2001–2020 period. It is concluded from the empirical findings that all exogenous variables except population density have a significant effect on the recycling rate.

Best Available Technology for P-Recycling from Sewage Sludge—An Overview of Sewage Sludge Composting in Austria

In order to close the phosphorus cycle in the long term, efficient recycling processes are necessary to ensure that this critical nutrient can be returned to arable land. Sewage sludge recycling is of particular importance due to the relatively high phosphorus content of sewage sludge. In this article, the current recycling paths of Austrian sewage sludge are highlighted, focusing on the advantages and limitations of sewage sludge composting. In addition to nutrient contents, pollutant loads were also analyzed in order to also discuss the limitations of this recycling pathway. Therefore, data from Austrian composting plants with focus on sewage sludge are used. The results show that the currently relevant pollutants (heavy metals) are predominantly below the limits prescribed for recycling and spreading on arable land. However, in order to decide on a recycling path at an early stage, a pollutant monitoring system must be in place. Due to pollution, mono-incineration with subsequent phosphorus recovery is also currently being discussed in Austria. Mono-incineration can represent an important component of sewage sludge disposal, because some sewage sludges are not suitable for composting due to potential environmental hazards. Therefore, it is important that evidence-based limit values and measures for the reduction in pollutants for input sources are determined.

Assessment of Biodegradation and Eco-Toxic Properties of Novel Starch and Gelatine Blend Bioplastics

To combat the release of petroleum-derived plastics into the environment the European Commission has adopted the EU plastics strategy, which aims for a complete ban on single-use plastics by 2030. Environmentally friendly and sustainable packaging like bioplastic is being up taken at significant levels by companies and consumers. In this study, the environmental impact of novel gelatine–starch blend bioplastics is investigated. The assessments included ecotoxicology with different species that can be found in marine and soil environments to simulate natural conditions. Microalgae, plant, and nematode species were chosen as these are representative of their habitats and are known for their sensitivity to pollutants. Degradation rates of these novel bioplastics were assessed as well as microbiome analysis of the soil before and after bioplastic degradation. The main findings of this study are that (i) the bioplastic generated can be fully biodegraded in soil environments at moderate conditions (20 °C) leaving no physical traces; (ii) bioplastic did not exhibit significantly adverse effects on any organisms assessed in this study; (iii) microbiome analysis of the soil after biodegradation showed a decrease in alpha diversity and a significant increase of Actinobacteria and Firmicutes phyla, which were dominative in the soil.

Avoidable Household Food Waste: Diagnosing the Links between Causes and Composition

Problems associated with the wastage of food intended for human consumption are well known and the discarding of edible but unconsumed food—avoidable food waste—is clearly undesirable. Interventions to reduce avoidable food waste need to be suitably informed: understanding the causes and consequences of avoidable food waste is instructive in this regard. One hitherto unexplored approach to understand better the causes of food waste is to elucidate associations between the composition of avoidable food waste and the reasons why it is generated. If such associations can be established, data relating to the composition of avoidable food waste can contribute evidence to underpin interventions intended to prevent or reduce avoidable food waste. The aim of this study was therefore to explore links between the causes of avoidable food waste and its composition, and thereby contribute to the development of management measures. Information relating the commonly reported causes of avoidable food waste and its composition (part-consumed, whole-unused and leftovers) was gathered via a series of participatory workshops involving university students. Outcomes of the workshops indicated that individual causes of avoidable food waste rarely lead exclusively to a single type of avoidable food waste, but some relationships were evident. Five of the 13 causal factors explored were considered to lead to all three types of avoidable food waste; a further five were considered to lead mainly to part-consumed and whole-unused food waste. Potential interventions to effect positive change are explored; the value of classifying avoidable food waste to guide interventions was evident, although approaches would need to be aligned with the observed composition of avoidable food waste and the method(s) of intervention considered. Applications of the approach and outcomes of this study are also considered in a policy context.

A Review of Glass Fibre Recycling Technology Using Chemical and Mechanical Separation of Surface Sizing Agents

Glass fiber is widely used in various modern industrial applications because it has the advantages of good electrical insulation performance and good process ability. Inevitably, some flawed glass fiber generated during manufacturing processes becomes waste and, in recent years, the treatment or recycling of glass fiber waste has become an environmental concern. Since glass fiber is brittle, non-wearing, and can easily generate static electricity after friction, the surface of glass fiber must be coated with a wetting agent (i.e., surface sizing agent) to overcome these disadvantages. However, glass fiber waste cannot be directly recycled as glass raw materials due to the presence of the surface sizing agent and the high content of sodium element. Therefore, there is a need to develop a feasible technology for removal of surface sizing agent in order to recycle glass fiber waste. In this study, two methods were used to remove surface sizing agent from glass fiber waste. After removing the surface sizing agent, the treated glass fiber waste can replace sand particles for manufacturing controlled low-strength material (CLSM). The first method for removing surface sizing agent used different organic solvents such as ethyl acetate to dissolve the surface coating (i.e., surface sizing agent). Then, an optical microscope was used to observe the surface changes before and after such removal treatments. The second method involved grinding glass fiber waste into a fine powder and heating it to a high temperature. An X-ray diffractometer (XRD) and X-ray fluorescence (XRF) were used to analyze the surface characteristics of the glass fiber waste. The experimental results showed that different organic solvents could not effectively remove the surface sizing agent, even if the glass fiber waste was processed by ultrasonic vibration for 5 h. In contrast, after high heating at 800 °C for 2 h, the surface sizing agent could be removed, and glass fiber waste transformed to cristobalite. The CLSM concrete produced by mixing cristobalite with cement in an appropriate proportion can meet the CLSM specification standard in Taiwan.

Recycling of Rubber Wastes as Fuel and Its Additives

Economic, social, and urban developments generally require improvements in the transportation sector, which includes automobiles such as trucks, buses, trailers, airplanes, and even bicycles. All these vehicles use rubber tires. After consumption, these tires become waste, leading to enlarged landfill areas for used tires and implying additional harm to the environment. This review summarizes the growth of rubber recycling application and the sustainability of using waste rubber in the construction field. Furthermore, we provide methods to convert rubber waste to fuel or fuel additives by using tire-derived fuel and concentrate to pyrolysis, which are environmentally friendly and efficient ways. The related parameters such as temperature, pressure, and feedstock composition were studied. Most research papers observed that 500 °C is the optimal temperature at atmospheric pressure in the presence of a specific type of catalyst to improve pyrolysis rate, oil yield, and quality.

Comparison of Properties with Relevance for the Automotive Sector in Mechanically Recycled and Virgin Polypropylene

Polypropylene (PP) has a high recycling potential. However, the properties of mechanically recycled PP (R-PP) have not been fully compared to those of virgin PP (V-PP). Therefore, in this study, properties of R-PP and V-PP were compared using data from recyclers, virgin plastic suppliers, and the literature. The properties of recyclates could not be directly correlated either with the properties of the virgin polymers from which the recyclates were made or the recycling parameters. It was found that the MFR of R-PP was higher; MFR R-PP had a median value (m) of 11 g/10 min while MFR V-PP had a median value of 6.3 g/10 min (at 230 °C and with 2.16 kg). In terms of mechanical properties, in many cases R-PP exhibited stiffer and more brittle behavior, with a slightly higher Young’s modulus (ER-PP = 1400 and EV-PP = 1200 MPa), a reduced elongation at break (ɛbR-PP = 4 l.-% and ɛbV-PP = 83 l.-%), and notched charpy impact strength (NCISR-PP = 4.8 and NCISV-PP = 7.5 kJ/m2). However, the values for every property had a broad distribution. In addition to existing information from the literature, our research sheds fresh light on the variation of the characteristics of recycled polypropylenes presently on the market.

Enhancement of WEEE Management Practices in MTN Phone Village, Rumukurushi, Port Harcourt, Nigeria

Informal recycling has been a source of challenges to a mobile telephone network (MTN) phone village in Rumukurushi, Port Harcourt, Nigeria, and several locations in developing countries. In order to bring a lasting solution to the menace of informal recycling in this location, the study proposed a new waste electrical and electronic equipment (WEEE) management system. The system comprises the application of two key concepts. The first concept includes limiting the activities of informal recyclers to WEEE collection only. This implies WEEE treatment, dismantling, etc., are carried out by government-approved agencies and experts. The second concept involves the application of the just-in-time (JIT) management concept for managing WEEE. The concept ensures that WEEE is only requested from the recycler or the individuals in possession of it and only on demand. The study adopted a qualitative research approach. Data collection and analysis were achieved via semi-structured phone interviews and thematic analysis, respectively. The outcome of the study limits the activities of the informal recyclers to WEEE collection. Informal recyclers gain revenue from collection. A reduction in the waiting time of workers and WEEE storage space is achieved. This offers safety, efficiency, and an increased productivity. This will help to revolutionise the WEEE management system in the location.

Identifying and Evaluating Recirculation Strategies for Industry in the Nordic Countries

The manufacturing industry in the Nordic countries aims to include closing product and material loops to recover values in their circular economy strategies. Recirculating strategies for products and materials are required for existing products that are part of the stock and are also anticipated to be aligned with products designed for circularity and circular business models in the future. Options to capture value of discarded products are diverse and include reuse, remanufacturing and material recycling. The Circular Economy Integration in the Nordic Industry for enhanced sustainability and competitiveness (CIRCit) project developed a framework to guide decision makers in the industry on how to identify suitable treatments and subsequent use at the end of use or end of life of a product and how to select among different options. Factors considered in the assessment include technical feasibility, necessary efforts, networks of business partners, legal implications and overall sustainability aspects. Our empirical studies show great support for decision-makers in the value recovery of different products with different complexity levels. It is also concluded that the properties of products at their end of use are the main drivers behind selecting a proper recirculation strategy. This study contributes with an empirical evaluation and a consistent terminology framework for recirculation options. The general setup is relevant for the Nordic countries.