Degradation of excavated polyethylene and polypropylene waste from landfill

In 2016, it was estimated that 7.4 million tonnes of plastic waste have been disposed in landfill in Europe. This waste represents an important opportunity for resource recovery through enhanced landfill mining consistent with recent Circular Economy initiatives. However, a recent review found a lack of data describing the degradation of excavated plastic waste and the potential impact on recycling products such as pyrolysis oil. In this study, the physicochemical characteristics of the main plastic types found in landfills and their implications for recovery and recycling were investigated using a combination of scanning electron microscopy energy dispersive spectroscopy (SEM-EDS), attenuated total reflectance Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Loss of gloss was visually detected for the buried plastic waste samples (polyethylene (PE) and polypropylene (PP)) compared to fresh plastic samples. The SEM-EDS analysis further showed that oxygen was the main element related to the plastic surface alteration. The carbonyl index (CI) of plastic samples buried for >10 years was between 1.5 and 2 times higher than 10 years) was 2 times higher than the fresh and < 10 years samples. Based on these findings, tertiary recycling, such as pyrolysis, seems to be a convenient route for upcycling of recovered plastics from municipal solid waste landfills

Artemis and her territory : toponymic and topographical cult-epithets of Artemis in Attica

This paper analyses some topographical and toponymic cult-epithets of Artemis at-tested in Attica. In the multiform panorama of Greek religion, epithets had the function of defining the sphere of influence of deities in order to accommodate the needs of the community of worshippers involved in specific cults. Artemis is one of the deities whose sphere of influence is most strongly connected to specific geographical areas. She is frequently honoured in sanctuaries located in borderline and extreme positions from which she presides over initiation rituals and operates as the guardian of the frontiers. The connection between Artemis and specific geographical areas is testified by Callimachus who details her dominion over the mountains, patronage of thirty cities, and supervision of streets and harbours. Across the Greek world, this connection is demonstrated by a series of topographical and toponymic cult-epithets that variously define her domains and her functions within these domains, as well as the origin of specific cults and their locatio

Developing the case for enhanced landfill mining in the UK

Across the UK there are around 22,000 landfills sites, suggesting a significant opportunity for recovering value from previously discarded materials. Enhanced landfill mining (ELFM) has been identified as a concept to recover value from landfills through optimized valorization of the resources extracted. This approach, including waste-to-energy (WtE), waste-to-material (WtM) and waste-to-land (WtL) options can also assist in addressing critical and secondary raw material demands and scarcity. However, to date, there is still limited evidence on this potential. In this paper, the results of 9 UK landfill sites characterization and feasibility studies for ELFM are presented. Waste characterisation from 9 landfill sites located in the UK was carried out. Overall 36 core drills and 118 unique waste samples were analysed. High volumes of fines (soil-like) organic material were observed across all samples and significant levels of valuable metals were observed in this fraction. Previous work had determined significant aluminium and copper are contained in the soil-like fines fraction, which does not include the separate metals fraction (i.e. aluminium cans, copper wires etc). At one site the combustible fraction was assessed as a potential refuse-derived fuel [RDF]. Typically, 10-40% by weight of the samples at this site were ‘combustible’, with an average gross calorific value of 12.9 MJ/kg. Plastics extracted from the sites are contaminated and degraded, therefore further work is required to understand the extent of degradation and to assess available options upcycle these materials

Dedication of Axios and Kapo to Artemis Nanaia and the Phosphorion of Piraeus

Nanaia is a Babylonian deity who was associated with Artemis in Hellenistic times. She is identified as a moon goddess as well as a deity of love and war, and as a protector of the sovereign and the country. The reason behind the assimilation between this oriental deity and Artemis lay in the commonality of functions between the two. The presence of a goddess called Artemis Nanaia is attested in Attica by an inscription found at Piraeus which is the only testimony of the presence of this cult in Greece. Like the goddess Nanaia, Artemis was a moon goddess, identified as a protector of political order. This function in Attica is expressed by the adjective Boulaia and by the practice, widespread since the second century B.C., of offering a sacrifice to Artemis Boulaia and Artemis Phosphoros before political assemblies in the Athenian Agora

Characterisation of excavated plastics for thermochemical upcycling to platform chemicals and liquid fuels

In Europe there are ~500,000 landfills; plastics represent a consistent and significant proportion of waste in landfill (typically 5-25% w/w). This fraction remains in the landfill, along with other non-biodegradable materials, long after the readily biodegradable organics have degraded. During storage in landfill the plastics physicochemical structure is likely to change because of the occurrence of chemical and biochemical reactions, which can lead to their degradation. For instance, H2S and organic acids produced during the acetogenesis phase of landfill are known to degrade plastics, therefore it can be hypothesised that plastics excavated from landfill are not suitable for conventional recycling. The fate of plastics in landfill has not been largely investigated and limited data exists addressing the changes in chemical and physical properties. The aim of this work is to investigate the degradation of plastics in landfill by characterising chemical and physical properties of samples excavated from different landfill depths. Waste samples were extracted from landfills across the UK at depths of 5-40 m. These were sorted in order to determine the total plastic content and the percentage of each type of plastic present (i.e. PET, HDPE etc). The types of plastics were identified using near infrared [NIR] spectroscopy. The surface properties of the excavated plastics were characterised using SEM/EDS to analyse and evaluate their degradation and contamination levels. Chemical characterisation of each plastic fraction has been carried out by proximate and ultimate analyses. Finally, the surface contamination (metal content) of the plastics was determined by ICP. Fresh, non-landfilled, plastic samples matching the plastic types of those found in landfill were characterised for comparison. The data highlighted plastic type variation across the samples, largely dependent on the age of the excavated material. The extent of degradation, was found to depend on the type of plastic and depth of the sample. This work contributes to address the potential utilisation of excavated plastics, such as for upcycling to platform chemicals and/or liquid fuels through thermochemical conversion

Bilateral neurotoxic lesions in NCM before tutoring onset do not prevent successful tutor song learning

Sensorimotor learning crucially depends on the ability to acquire a sensory memory for shaping motor commands. Such learning is conveniently studied in young songbirds when they memorize the song of an adult singer and gradually transform their own vocalizations toward the memorized target song. Here we study the involvement of the Caudal Medial Nidopallium (NCM), a higher auditory cortical area, in acquisition of a song memory. NCM has previously been shown to be involved in tutor song memorization. To study the necessity of NCM in this process, we perform large irreversible NCM lesions using ibotenic acid injections in about 40-days old juvenile zebra finches, before their first exposure to tutor song. Surprisingly, NCM-lesioned juveniles successfully copied the tutor song at least as well as untreated control animals, showing that a fully intact NCM is not required for tutor song memory formation and normal song development

Physico-chemical properties of excavated plastic from landfill mining and current recycling routes

In Europe over 5.25 billion tonnes of waste has been landfilled between 1995 and 2015. Among this large amount of waste, plastic represents typically 5–25 wt% which is significant and has the potential to be recycled and reintroduced into the circular economy. To date there is still however little information available of the opportunities and challenges in recovering plastics from landfill sites. In this review, the impacts of landfill chemistry on the degradation and/or contamination of excavated plastic waste are analysed. The feasibility of using excavated plastic waste as feedstock for upcycling to valuable chemicals or liquid fuels through thermochemical conversion is also critically discussed. The limited degradation that is experienced by many plastics in landfills (>20 years) which guarantee that large amount is still available is largely due to thermooxidative degradation and the anaerobic conditions. However, excavated plastic waste cannot be conventionally recycled due to high level of ash, impurities and heavy metals. Recent studies demonstrated that pyrolysis offers a cost effective alternative option to conventional recycling. The produced pyrolysis oil is expected to have similar characteristics to petroleum diesel oil. The production of valuable product from excavated plastic waste will also increase the feasibility of enhanced landfill mining projects. However, further studies are needed to investigate the uncertainties about the contamination level and degradation of excavated plastic waste and address their viability for being processed through pyrolysis

Thermal degradation kinetics of real-life reclaimed plastic solid waste (PSW) from an active landfill site:The mining of an unsanitary arid landfill

Landfilling is viewed nowadays as a serious threat associated with various burdens and stressors on the urban environment. To date, there is little information available on actual value of landfilled waste namely plastic solid waste (PSW) resulting from mining operations. In this work, PSW reclaimed from an active unsanitary landfill site (MAB) has been studied with the aim of determining its thermal profile and degradation behaviour for future utilisation in thermo-chemical conversion (TCC) processes. The materials were characterised by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) in accordance with internationally approved test methods in a simulated pyrolytic environment. In addition, chemical analysis using Fourier Transform Infrared Spectroscopy (FTIR) was applied to study the nature of the materials reclaimed. The degradation kinetics of the reclaimed PSW were studied with the aim of determining the apparent activation energy (Ea) of the pyrolytic reactions. The Ea values determined ranged from 199 to 266 kJ mol−1 which is in-line with pyrolytic reactions applicable for future use in fuel recovery units. TGA showed a clear shift in thermograms indicating a clear change in the degradation mechanism. The physico-chemical studies conducted on the materials also favours TCC treatment over other conventional end of life options such as physical (mechanical) recycling or incineration. The degradation mechanism was also determined from the Criado method showing that Avarami-Erofeve was the model that best represents PSW degradation. Overall, this work points towards future intervention schemes for reclaimed municipal solid waste (MSW) and in particular PSW favouring TCC technologies

Application of a neural fuzzy model combined with simulated annealing algorithm to predict optimal conditions for polyethylene waste non-isothermal pyrolysis

Adaptive neural fuzzy model Simulated annealing algorithm A B S T R A C T In the present study, the waste polyethylene (PE) pyrolysis under different non-isothermal conditions was investigated to estimate the optimal conversions and pyrolysis rates. The pyrolysis study was carried out using Thermogravimetry (TG) of the virgin and the waste PE under different heating rates of 5, 10, 15 and 20 C/min. The TG experiments indicated that the virgin and the waste PE pyrolysis processes mainly underwent in the temperature range of 390-510 C. Subsequently, the adaptive neural fuzzy model was adopted to predict the conversions and the pyrolysis rates of the virgin and the waste PE. The optimal operating conditions in different temperature ranges were optimized by the simulated annealing algorithm (SA). Moreover, the R-squared values of the virgin PE conversions (~1) and pyrolysis rates (> 0.999), and the waste PE conversions (~1) and pyrolysis rates (> 0.999) revealed the high accuracy of the adaptive neural fuzzy model predicted results

La ceramica miniaturistica di S. Leucio

Oggetto del contributo è l'analisi della ceramica miniaturistica rinvenuta durante le indagini archeologiche che hanno interessato l'area della basilica di S. Leucio a Canosa di Puglia. Lo studio ha permesso di rintracciare tre diverse forme ceramiche: brocche, olle e boccali. Gli esemplari, tutti di argilla depurata lavorata al tornio, sono caratterizzati da standard dimensionali compresi tra i cm 3,5 e i cm 7 di altezza. Tali materiali trovano confronti in vari contesti votivi e funerari dell'Italia meridionale