Waste Management & Research: The Journal for a Sustainable Circular Economy

One of the most crucial parts of solid waste management is determining landfill site location, since multiple factors must be considered and there is no universal formula. The main purpose of this study is to make a worldwide systematic review of restriction criteria used for landfill siting using geographic information systems (GIS). Literature from the last years was thoroughly assessed, and 45 restrictions found were classified as environmental, economic, or social criteria. Our findings show that although the number of articles published has increased recently, they use on average seven restrictions, focusing mainly on environmental over economic and social criteria. In our boxplot statistical analysis, the most frequently used environmental restrictions are the distance from surface water resources (used in 77% of articles), slope (52%), and distance from groundwater founts (40%), with a median of 300 m, 20%, and 250 m, respectively. The most frequently used economic restrictions are distances from roads (60%), airports (40%), and power lines (18%), with medians of 275 m, 3000 m, and 75 m, respectively. The most frequently used social restrictions are distances from urban areas (45%), settlements and residential areas (40%), and cultural heritage or archaeological areas (23%), with medians of 1000 m. This information might help, on the one hand, governments to develop new legislation about landfill siting and on the other hand, decision-makers and scientists to produce new studies with different restrictive scenarios.

In the Italian authorization procedure for the construction of a landfill, the risk analysis (RA) is mandatory in case of request for derogation from the current legislation (Ministerial Decree (D.M.) 27 September 2010) in order to demonstrate that there is no risk for the environment. This paper describes the experience of the Province of Brescia, public body appointed for giving authorizations for new landfills, and its collaboration with the University of Brescia for the specific topic of RA applied to landfills. The research was undertaken because a lack of complete and specific indications about the application of such methodology to landfills has been identified. In particular, the province of Brescia faced the issue of verifying the proper application of such methodology in relevant cases. After referring to the legal and technical framework, including the current national legislation and a summary of the technical documents available for the topic (guidelines and instructions by technical bodies), the paper outlines the technical-preliminary approach applied by the Province of Brescia. This is complemented by a description of the methodological approach followed for RA for groundwater and for gaseous emissions, with a focus on biogas, together with the presentation of the results for three relevant case studies. The critical aspects that were faced and the proposal to overcome them, which are under discussion with the responsible bodies, are described as well.

Agricultural biomass can be best described as the organic matter residues from farming that remain within the fields after harvesting, along with tree trimmings. From the overall Greek Energy Balance, only a small fraction consists of biomass and this has been the main driving force behind this study. Due to the numerous ongoing agricultural activities, western Greece was selected as an ideal area for a case study. As a second step, the aim was to investigate the feasibility of the current anaerobic digestion plants to utilize the total biomass as feedstock. An additional scope to provide certifiable proof of the essential rural biomass assets available. Information on the potential of agricultural biomass is provided, with a focus on the performance specifications and the social advantages, but also the soil added substances and the produced biofuels. Subsequently, two options for waste management were discussed to illustrate the possibility of generating energy. The anaerobic digestion plants available in western Greece are illustrated in detail and the yearly rate of the main agrarian biomass is evaluated to be 715,080 tons. Arable crops, mechanical plants and tree trimming are recorded as the noteworthy sources. It is estimated that the proposed anaerobic digestion system will handle the entire amount of biomass and deliver max per year electricity 775 GWh and thermal energy 1.119 GWh.

Europe is considered one of the most attractive and safe prevalent tourist destinations in the entire world. Approximately half (47.4%) of European tourist visits occurred in coastal regions, defined “on the basis of and consist of local administrative units or municipalities that border the sea, or have at least half of their total surface area within a distance of 10 km from the sea.” Destinations such as Malta, Greece, Cyprus, Spain and Croatia presented with an increased level of tourist accommodation establishments, as well as, the overall flow of tourism in the European Union is mostly concentrated on Mediterranean coastal regions (as nine out 10 tourists, in 2015, spent their holidays at coastal areas). This paper, is dealing with the assessment of a tourist area and how the concept of urban metabolism has been affected by touristic activities. Moreover, this research using several key performance indicators such as waste compositional analysis, the clean coast index, the accumulation rate, and accumulation index, etc., tries to measure the level of environmental performance, and furthermore, to assess the existing infrastructures and the waste management plan, that are being implemented. The results are very useful, for any policy-maker, as well as competent authorities and/or tourist organizations which are dealing with tourist activities and aim to propose or re-schedule any waste strategy targeting the goals of United Nations Sustainable Development Goals, European Green Deal, and the new circular economy strategy.

Pulp and paper manufacturing and recycling industries are a resource-intensive sector, generating 25–40% of the annual municipal solid waste worldwide. Waste includes abundant volumes of paper sludge, as well as the product of its incineration, namely paper sludge ash. These two waste materials are both predominantly landfilled. There is thus a drive for additional valorisation routes for these materials. This short communication focuses on the potential use of paper sludge ash in alkali-activated cement concrete; this type of concrete was estimated to potentially reduce CO₂ emissions by up to 5–6 times, while it can also incorporate waste materials or industrial by-products in its composition. The paper presents a laboratory study assessing the feasibility of structural alkali-activated cement concrete with ground granulated blastfurnace slag (a by-product of steel production) and paper sludge ash. Paper sludge ash is used mainly as a source of Ca(OH)₂ in the alkaline activator solution, and secondly as an additional source of aluminosilicates. A number of factors potentially affecting the activation process and the resulting concrete quality were investigated, including different dosage of activators, curing conditions and curing time. Mixes with paper sludge ash in the activator system developed high early concrete strengths at ambient temperatures and maintained adequate strengths for structural concrete. Further mix optimisation and mechanical and durability testing, accompanied by material characterisation, are required to establish the advantages of using this waste material in structural alkali-activated cement concrete.

Around 6 million tonnes of edible food are being wasted (post-farm gate) in the UK each year. This fraction of edible wasted food is known as avoidable food waste. In a circular economy food is a valuable resource that must be captured at all stages of the food supply chain and, where possible, redistributed for consumption. This can prevent avoidable food waste generation, and dissipation of food’s multidimensional value that spans environmental, economic, social, technical and political/organisational impacts. While the importance and benefits of surplus food redistribution have been well documented in the global literature, there are still barriers that prevent perfectly edible food from being wasted. This study looks at the main stages of the food supply chain, and amasses the opportunities, challenges and trade-offs associated with surplus food redistribution to the UK economy. It highlights points in the food system where interventions can be made, to improve food’s circularity and sustainability potential. Stakeholder interrelations, regulatory and socio-economic aspects are discussed in relation to their influence on decreasing avoidable food waste. The main output from this work is a diagrammatic depiction of where challenges and trade-offs occur along the food supply chain, and how policy and socio-economic reforms are needed to maximise avoidable food waste prevention, and the surplus avoidable food redistribution in the food supply chain for social benefit.

The SWAN platform is an integrated suite of online resources and tools for assessing industrial symbiotic opportunities based on solid industrial waste reuse. It has been developed as a digital solid waste reuse platform and is already applied in four countries (Greece, Bulgaria, Albania and Cyprus). The SWAN platform integrates a database with the spatial and technical characteristics of industrial solid waste producers and potential consumers, populated with data from these countries. It also incorporates an inventory of commercially implemented best practices on solid industrial waste reuse. The role of the SWAN platform is to facilitate the development of novel business cases. Towards this end, decision support services, based on a suitable matching algorithm, are provided to the registered users, helping them to identify and assess potential novel business models, based on solid waste reuse, either for an individual industrial unit (source/potential receiver of solid waste) or a specific region.

Reliable prediction of municipal solid waste (MSW) generation rates is a significant element of planning and implementation of sustainable solid waste management strategies. In this study, the multi-layer perceptron artificial neural network (MLP-ANN) is applied to verify the prediction of annual generation rates of domestic, commercial and construction and demolition (C&D) wastes from the year 1997 to 2016 in Askar Landfill site in the Kingdom of Bahrain. The proposed robust predictive models incorporated selected explanatory variables to reflect the influence of social, demographical, economic, geographical and touristic factors upon waste generation rates (WGRs). The Mean Squared Error (MSE) and coefficient of determination (R²) are used as performance indicators to evaluate effectiveness of the developed models. MLP-ANN models exhibited strong accuracy in predictions with high R² and low MSE values. The R² values for domestic, commercial and C&D wastes are 0.95, 0.99 and 0.91, respectively. Our results show that the developed MLP-ANN models are effective for the prediction of WGRs from different sources and could be considered as a cost-effective approach for planning integrated MSW management systems.

This study evaluated the performance of a plug-flow reactor (PFR) for high-rate anaerobic co-digestion of complex agro-industrial wastes and used cooking oil or animal fat. The PFR was successfully operated up to an organic loading rate (OLR) of 21 g L⁻¹ d⁻¹, yielding biogas at 0.35 L g⁻¹ chemical oxygen demand (COD) influent. During the study period, supernatant COD at the PFR effluent remained between 4 and 7 g L⁻¹, with negligible volatile fatty acids’ concentrations (<500 mg L⁻¹) and no presence of foaming incidents. The biomass concentration inside the PFR, expressed as total suspended solids, remained between 30 and 60 g L⁻¹. Moreover, the above-mentioned anaerobic digestion technology has been currently scaled-up at 50 m³ PFR, while a full-scale facility of 240 kW-el is under construction in the region of north-eastern Greece.