17 Jul 2019, 11:41 pm
Waste Management & Research
Waste Management &Research, Ahead of Print.
The asbestos-containing waste management is a public health topic for countries which have used this mineral. Treatment of chrysotile (white asbestos), a phyllosilicate from serpentine, crocidolite (blue asbestos, first results on this kind of asbestos), one of the five asbestos varieties of amphibole family and asbestos-containing waste conversion process is proposed by using hydrothermal treatment in supercritical water. All samples were treated in an Inconel Batch Reactor. The treatment durations range is from 1 to 6 hours, temperatures range is from 400°C to 750°C, mass concentration range is from 0.02 to 170 mg. mL−1 and pressures are higher than 23 MPa. Ultrapure water is used for sample preparation. This ultrapure water is used to monitor mineral leaching on the aqueous phase and to avoid particle cross-contamination. Transmission electron microscopy analyses were carried out to check the presence or not of asbestos phase. According to these analyses, the best conditions of conversion were 1 hour and 0.02 mg. mL−1 for chrysotile, 3 hours and 0.02 mg. mL−1 for crocidolite and 1 hour and 20 mg. mL−1 for asbestos-containing waste, at T = 750°C. Supercritical water conditions were maintained during the whole treatment. The X-ray diffraction showed that the main phases present after treatments were riebeckite and magnetite (crocidolite), forsterite and enstatite (chrysotile), and calcite, spurrite and gehlenite (asbestos-containing waste). Finally, a scanning electron microscopy analysis was performed to monitor morphological fibre change. The elongated structure, partially fragmented, was found in all samples.
3 Jul 2019, 12:18 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
The usage of plastics has exponentially increased in our daily lives over the past 50 years because of its durability, low costs and potential for diverse applications, such as widespread use as disposable items. In this study, first, the recycling cost of plastic wastes has been estimated by using actual data taken from a recycling centre, where plastic solid wastes were collected separately. The total amount of plastic wastes recycled at the centre was approximately 695 tonnes. The operating cost of plastics separation at the recycling centre, the transport of plastic wastes, labouring, maintenance, electricity, insurance and chemical costs were taken into consideration in the cost evaluation. Accordingly, the unit cost of recycling was calculated as US$0.40 kg−1 of plastic waste. This cost was compared with the predicted plastic recycling cost in the same region using statistical values. The predicted recycling cost was estimated based on assuming segregated collection by the municipalities of all PSW in municipal solid waste. Then the resulting unit cost of recycling was found to be US$0.25 kg−1 of plastic waste. In addition, the recycling costs were also evaluated including the revenue from the sales of recycled plastic granular. According to the evaluated total cost of plastic recycling, it can be concluded that mechanical recycling of plastics can only be an economical option if the recovery of plastics is improved.
3 Jul 2019, 12:17 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
The outstanding pace of technological development around the world coupled with increasing population and rapid urbanization have brought along an ever-increasing demand for healthcare services. This trend results in an increasing amount and variety of medical wastes. Accordingly, the issue of effective collection, transportation and disposal of medical wastes, specifically in large cities, has become a critical concern from the viewpoint of urban logistics and holds great importance in terms of safety. This study aims to determine the safety of hospitals in their medical waste management function. The study involves the determination of medical waste management steps, establishment of a hierarchical structure, and weighting of the criteria within the established hierarchical structure by means of the analytic hierarchy process method. Afterwards, the extent to which these criteria are adopted in hospitals was evaluated by the medical waste management officers of those hospitals, and safety scores were obtained for each hospital by associating the results with the weighted values obtained by the analytic hierarchy process method. The model proposed for medical waste management problems encountered by healthcare institutions in Istanbul was implemented for a specific region of Istanbul province, and the obtained results were analyzed. Evaluation of the opinions of the healthcare officials for determination of the medical waste management safety scores showed that the “collection” criterion has significantly higher importance than the “temporary storage” and “transportation” criteria. “The effect on hospital personnel” sub-criterion of the “collection” criterion had the highest score. This revealed the importance of the collection process that takes place between storage and transportation, for evaluating the human waste-based risks.
3 Jul 2019, 12:16 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
Healthcare waste encompasses a significant quantity of hazardous substances. Poor healthcare waste management can result in serious environmental and human health risks. Asian developing countries are densely populated, and some are highly resource constrained. These countries commonly fail to practice appropriate healthcare waste management. Moreover, facilities in these countries extensively lack proper waste segregation, collection, safe storage, transportation, and disposal. This mini-review recapitulates key issues of healthcare waste management confronting Asian developing countries. Regulations, legislation, and policies are found to be recent, and their implementation varies from one another. Variation in waste generation rate is common. Contradictory methods of waste measurement used by researchers leave these variations questionable. The absence of waste management training programmes roots ignorance among staff and handlers, which leads to unsafe waste handling and causes different health risks. Unsafe and illegal recycling of hazardous waste is a threat to human health, also landfilling is often confused with open dumping, causing environmental damage. Outdated incineration plants need to be replaced with autoclaving, steam sterilisation, and comparatively reasonable new practice of pyrolysis to avoid the emission of toxic gases. The significance of proper healthcare waste management cannot be ignored, especially in Asian developing countries; substantial improvements are required in order to protect the environment and human health from serious risks.
3 Jul 2019, 12:16 am
Waste Management & Research
Waste Management &Research, Ahead of Print.
The treatment and disposal of industrial waste has become a critical economic and environmental issue with the ever-increasing rates of its generation. Industries in India, as major players in building the economy and GDP, expel about 7.4 million tons of hazardous waste annually, out of which around 3.98 million tons are recyclable for resource or energy recovery. India’s scenario in the usage of alternative fuel and raw material is less than 1%, which reflects a huge quantum of hazardous waste for potential usage in alternative fuel and raw material. The Netherlands, with around 83% of total hazardous waste, is the highest user of hazardous waste as alternative fuel and raw material in cement kilns. Uncontrolled waste management degrades land, ground water and air quality, leading to health risks to humans, animals and the ecosystem. Presently, industrial waste in most cases is disposed to landfills after incineration, without utilizing the full potential of the wastes through recirculation. The present study analyzed the current situation of the treatment facilities for attaining a sustainable management system using waste as alternative fuel and raw material for the disposal of hazardous waste. Through the alternative fuel and raw material concept, hazardous wastes can be used as a substitute for fossil fuels and/or raw material in a few types of industries. This will surely enhance the efficient recirculation of industrial wastes. This paper presents the overall view of Indian hazardous-waste generating industries, their locations, the potential of wastes as alternate sources of fuel to other industries, the use of alternative fuel and raw material by cement industries and applicable regulatory requirements.
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.