2 Jul 2019, 2:34 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Accurate prediction of municipal solid waste (MSW) generation is necessary for choosing appropriate waste treatment methods and for planning the distribution of disposal facilities. In this study, a hybrid model was established to forecast MSW generation through the combination of the ridge regression and GM(1,N) models. The hybrid model is multivariate and involves total urban population, total retail sales of social consumer goods, per capita consumption expenditure of urban areas, tourism, and college graduation. Compared with the constituent models alone, the hybrid model yields higher accuracy, with a mean absolute percentage error (MAPE) of only 2.59%. Through weight allocation and optimal treatment of residuals, the hybrid model also balances the growth trends of the individual models, making the prediction curve smoother. The model coefficients and correlation analysis show that population, economics, and educational factors are influential for waste generation. MSW output in Hangzhou will gradually increase in the future, and is expected to reach 5.12 million tons in 2021. Results can help decision makers to develop the measures and policies of waste management in the future.
29 Jun 2019, 12:19 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Managing waste electrical and electronic equipment is currently one of the top priority challenges of waste management in the European Union. The collection and subsequent processing of waste electrical and electronic equipment are realized by means of the so-called collective systems that employ collection boxes varying in size and materials used for their production. This study focuses on quantifying and comparing environmental impacts of often-used collection boxes on the example of mobile phone collection. The comparison was based on volume (20 l, 60 l, and 70 l) and on the material used for the construction of the box (polypropylene, corrugated cardboard, and stainless steel). Other parameters, such as lifetime, material and energy performance for production, end of life stage, and waste generation were taken in account. The evaluation was carried out using the method of life cycle assessment with the characterization model CML 2001 created in GaBi 8. The goal of the study was to identify the box with the smallest environmental impact and to identify the hotspots in the life cycles of the individual collection boxes. The results of the study show that polypropylene boxes are the most environmentally suitable for collecting small waste electrical and electronic equipment as they produce the lowest environmental impacts in all of the impact categories evaluated, while boxes made of stainless steel have been found to represent the least environmentally friendly option. The results of the study provide and suggest to the collective system basic data for choosing the type of collection box.
27 Jun 2019, 4:34 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Landfill site selection is a relevant and necessary issue for waste management. However, it is an extremely complex task since it must take into account different environmental, economic and socio-political criteria that need to comply with strict regulations and meet different opinions. Accordingly, in this paper we propose a multi-criteria EVIAVE-(Evaluación del impacto ambiental en vertederos) based approach to evaluate the suitability of a set of possible landfill locations and rationally provide an optimal location for a landfill. The approach requires a comprehensive analysis to identify the best feasible site(s) that minimize a Global Landfill Risk Index (GRI), focused on environmental, economic and administrative impacts, and simultaneously comply with governmental regulations and constraints. This GRI is based on the Environmental Landfill Index, Administrative Landfill Index, Environmental Risk Index, Environmental Value, Probability of Contamination and Contamination Risk Index. An innovative feature of this approach lies in incorporating a mathematical model that combines weighted environmental and administrative issues. The model not only provides an optimal landfill location but also establishes landfill location ranks according to indexes of interest. This methodology reveals flexibility and high adaptability, being a useful and effective tool in the decision-making process. The methodology presented was tested with data available from a preliminary study developed in the municipalities of Oporto Metropolitan Area, Portugal, for the implementation of a multi-municipal landfill, which considers nine different locations for analysis.
27 Jun 2019, 4:32 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Heavy metals such as Co, Li, Mn, Ni, etc. and organic compounds enrich spent lithium-ion batteries (LIBs). These batteries seriously threaten human health and the environment. Meanwhile, with the development of new energy vehicles, the shortage of valuable metal resources which are used as raw materials for power batteries is becoming a serious problem. Using proper methods to recycle spent LIBs can both save resources and protect the environment. Pyrometallury is a kind of recycling method that is operated under high temperature with the aim of recovering useful metals after pre-treatment and organic binder removal with the characteristic of high temperature and it is easy to operate. Hydrometallurgy is characterized by high recovery efficiency, low reaction energy consumption, and high reaction rate, and is widely used in the recycling process of spent LIBs. During biometallurgy, valuable metals in the spent LIBs are extracted by microbial metabolism or microbial acid production processes. Since the drive for green and low secondary pollution, biometallurgy as well as solvent extraction and the electrochemical method have earned more attention during recent years. This mini-review analyzes the relationship between the emergence of new energy vehicles and the recycling status of spent LIBs. Meanwhile, this paper also consists of detailed treatment and recycling methods for LIBs and provides a summary of the management regulations of current waste for LIBs. What is more, the main challenges and further prospects in terms of LIBs management in China are analyzed.
27 Jun 2019, 4:31 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
In the project ‘NEW-MINE’ the use of sensor-based sorting machinery in the field of ‘landfill mining’ is investigated. Defilements pose a particular challenge in the treatment and sorting of plastics contained in landfills. For this reason, the effects of various pollutants caused by the interactions in the landfill body or the mechanical treatment steps in landfill mining are examined. In the following elaboration, the focus is on the influences of surface moisture and surface roughness of plastics on sensor-based sorting by means of near-infrared technology. Near-infrared radiation (NIR) in a wavelength range of 990 nm to 1500 nm has been used for the detection and classification of plastic particles. The experiments demonstrate that increased surface roughness reduces signal noise and thereby improves the classification of both spectrally similar and transparent plastics, but reduces the yield of low-softening plastics because their sliding speed on a sensor-based chute sorter varies as a result of the heating of the chute. Surface moisture causes the absorption of radiation from 1115 nm (high density polyethylene [HDPE], linear low density polyethylene [LLDPE], polyethylen terephthalate [PET] and polyvinylchloride [PVC]) or from 1230 nm (low density polyethylene [LDPE], polypropylene [PP] and thermoplastic polyurethane [TPU]) up to at least 1680 nm, which causes amplification or attenuation of various extremes in the derivative. However, the influence of surface moisture on the yield of plastics is usually very low and depends on the spectral differences between the different plastics.
20 Jun 2019, 3:04 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Bioplastics are emerging on the market as sustainable materials which rise to the challenge to improve the lifecycle of plastics from the perspective of the circular economy. The article aims at providing a critical insight of research studies carried out in the last 20 years on the degradation of bioplastics under aerobic composting and anaerobic digestion conditions. It mainly focuses on the various and different methodologies which have been proposed and developed to monitor the process of biodegradation of several bioplastic materials: CO2 and CH4 measurements, mass loss and disintegration degree, spectroscopy, visual analysis and scanning electron microscopy. Moreover, across the wide range of studies, the process conditions of the experimental setup, such as temperature, test duration and waste composition, often vary from author to author and in accordance with the international standard followed for the test. The different approaches, in terms of process conditions and monitoring methodologies, are pointed out in the review and highlighted to find significant correlations between the results obtained and the experimental procedures. These observed correlations allow critical considerations to be reached about the efficiency of the methodologies and the influence of the main abiotic factors on the process of biodegradation of bioplastics.
20 Jun 2019, 3:03 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Solid waste composting has never been practised on a full scale in Jordan. However, the National Solid Waste Management Strategy recommended five major composting facilities to be put into operation starting from 2025. According to the Ministry of Environment, the waste sector is contributing to 10.6% of the total greenhouse gas emissions of the country. The main objective of this study was to assess the potential of solid waste composting in mitigating greenhouse gas emissions in Jordan. Applying the upstream-operating-downstream account framework and developing a model that estimates the greenhouse gas emissions, it was possible to estimate the emissions associated with composting of source-segregated bio-waste, which was compared with three other scenarios, including business as usual (dumping and landfilling), sanitary landfilling, and anaerobic digestion. The assessment revealed that composting and anaerobic digestion of the total generated source-segregated bio-waste (Scenarios 3 and 4) have the least net greenhouse gas emissions with 1.1 million Mg CO2-eq y-1, while engineered sanitary landfilling and dumping have net emissions of 2.6 and 3.75 million Mg CO2-eq y-1, respectively. The findings of this research are paving the way to make informed and responsible decisions in the Jordanian solid waste sector to adopt sustainable and integrated management options.
20 Jun 2019, 3:03 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
The recycling processes of spent lithium iron phosphate batteries comprise thermal, wet, and biological and mechanical treatments. Limited research has been conducted on the combined mechanical process recycling technology and such works are limited to the separation of metal and non-metal materials, which belongs to mechanical recovery. In this article the combined mechanical process recycling technology of spent lithium iron phosphate batteries and the separation of metals has been investigated. The spent lithium iron phosphate batteries monomer with the completely discharged electrolyte was subjected to perforation discharge. The shell was directly recycled and the inner core was directly separated into a positive electrode piece, dissepiment, and negative electrode piece. The dissociation rate of the positive and negative materials reached 100.0% after crushing when the temperature and time reached 300 °C and 120 min. The crushed products were collected and sequentially sieved after the low-temperature thermal treatment. Then, nonferrous metals (copper and aluminium) were separated from the crushed spent lithium iron phosphate batteries by eddy current separation with particle size −4 + 0.4. The optimised operation parameters of eddy current separation were fed at speeds of 40 r min-1, and the rotation speed of the magnetic field was 800 r min-1. The nonferrous metals of copper and aluminium were separated by the method of pneumatic separation. The optimal air speed was 0.34 m s-1 for the particle-size −1.6 + 0.4 mm and 12.85–14.23 m s-1 for the particle-size −4 + 1.6 mm. The present recycling process is eco-friendly and highly efficient and produces little waste.
19 Jun 2019, 1:38 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Construction sites are plagued with numerous problems, such as improper planning and management, high amounts of waste generation and low awareness of waste reduction. Construction and demolition waste literature provides several best practises and prescriptive strategies that help minimise waste during construction. However, it lacks in the systematic identification and minimisation approach of all possibilities of waste. Therefore, studies focusing on principles and tools that help systematically analyse the inefficiencies of on-site processes leading to waste generation and philosophies addressing waste minimisation are necessary. As eliminating waste is one of the key lean principles, this article discusses the need and importance of integrating the lean construction with the construction and demolition waste management. This article aims to estimate and assess the causes of waste generation in a high-rise building construction through a case study in Chennai city (India) using value stream mapping, a key lean construction tool. Onsite monitoring and measurement were performed to quantify the amount of waste generated. A waste generation rate of 66.26 kg m−2 was identified, of which concrete, cement mortar and brick waste represented almost 90% of the total construction waste. Direct observation and interviews of site personnel were conducted to understand the causes of waste generation. A strategic framework has been proposed to improve construction and demolition waste minimisation depicting the synergy of combining lean construction principles with construction and demolition waste management strategies. The proposed framework helps in the systematic identification, assessment and minimisation of on-site construction waste generation.
11 Jun 2019, 11:59 pm
Waste Management & Research
Waste Management &Research, Ahead of Print.
Efficiency assessment and benchmarking are crucial for managing any organization. However, especially from a regulatory perspective, such efficiency assessment and benchmarking must be unbiased from context-specific issues and should provide an absolute rating, rather than a relative one. The current work reviews the approaches used for performance assessment and benchmarking waste collection services, revealing that the majority are biased and are not absolute, and proposes two alternative context-unbiased and absolute performance indicators, the collection capacity use (CCU) and the segregated waste collection efficiency (SWE). The proposed indicators were calculated for 246 utilities operating in Portugal. The utilities were then ranked accordingly, and their position was compared with the position attained using the equivalent performance indicators in the system currently in use by the Portuguese service regulator. The results reveal ranking differences of over 50 positions and illustrate how misleading the results from context-biased and relative metrics can be.