リサイクルと廃棄物管理の進歩

Waste electrical and electronic equipment (WEEE) is an important secondary source of valuable metals. Particularly discarded printed circuit boards (PCB) contain high concentrations of valuable metals, varying greatly among the type of board, the manufacture year, source device, and utilized PCB production technology. Chemical hydrometallurgical processing is an efficient method to selectively extract and subsequently recover metals from discarded polymetallic PCB. In this work, we propose a two-step process to extract copper (Cu) and gold (Au) from a discarded high-grade telecom server PCB. The boards contained 262.4 and 0.320 mg/g Cu and Au, respectively, which constituted the 98.1% of the total value of metals. The metal extraction process was optimized using Response Surface Methodology (RSM) by central composite design (CCD). The optimized process parameters showed that 3.92 M sulphuric acid, 3.93 M Hydrogen peroxide, 6.98% (w/v) pulp density and 3.7 hours contact time, and 0.038 M Copper sulphate, 0.3 M 0.38 M Ammonium Hydroxide, 10.76% pulp density (w/v) 6.73 hours were optimal for the maximal extraction of Cu and Au, respectively. At optimal conditions, 99.2% and 92.2% of Cu and Au, respectively, were extracted from the discarded PCB.

Expanded and extruded polystyrene (EPS and XPS) belong to the most often used insulation materials and with respect to this application-both material have been equipped with the brominated flame retardant hexabromocyclododecane (HBCDD) for more than 50 years. After HBCDD had been identified as a substance of very high concern, it was set under control of the Stockholm Convention and the European Reach legislation. In consequence, the use of HBCDD in insulation materials is currently phased out and waste insulation material made of HBCDD equipped EPS or XPS cannot further be subjected to state-of-the art mechanical recycling. However, as the majority of the formerly produced HBCDD equipped EPS and XPS is still in use as insulation material, more sophisticated recycling approaches are currently investigated. This study investigates a solvent based recycling process, which dissolves polystyrene from insulation waste and eliminates not only insoluble waste components but also co-dissolved HBCDD. The study investigates the efficiency of HBCDD removal as well as mechanical properties of recycled PS produced by this process.

This paper presents an examining household participation in 3Rs waste practice and the reasons of nonparticipant residents in 3Rs waste practice of the Region One Municipality of Tehran, Iran, and provide suggestions for improving the MSWM system through formulation of local 3Rs waste strategies, particularly on separation at source and recycling activities of the residents of Region One Municipality of Tehran, Iran which will help to promote the sustainable waste management. A household survey using a self-completing questionnaire was done in Region One Municipality of Tehran. A sample of 486 households participated in the household survey. The study revealed that only 26% of the households take part in waste reduction activities and 20% in practice reuse and 29% in separation at source. The traffic lights coding system model for ranking performance 3Rs-Reduce, reuse, and recycle, the participation rate of households in the case study area in 3R performance ranked between low/medium categories. Overall, survey results in the case study area about barriers to household’s participation in 3Rs waste practice are categorised under the three main categorise, behavioural, awareness and situational barriers.

Among the variables that could influence the citizens’ sense of a healthy environment, odor emissions play an important role, as they deeply affect the human life quality and psycho-physical wellness. An odor is a mixture of light and small molecules that are able to stimulate an anatomical response in the human olfactory system. Sensory analyses by odor panels are important in defining odorous nuisances. Biodegradable mist can be applied to liquid or solid waste, as a surface treatment, by incorporation, or dosing during processing.

As the limits of urbanization are extending to far flying areas in Addis Ababa, Sandefa Sanitary Landfill site has been established since December 2015. The new Sandefa Sanitary Landfill site is located about 35 km from Addis Ababa city and 5 km South-West of Lagedadi Dam, at North-Eastern side of Addis Ababa in Oromia Region, Finfine Zuria special zone, Bereh Woreda, in Ele Kebele close to a town called ‘Laga Tafo’. However, the new municipal solid waste landfill leachate is causing a great concern to the communities settled around. The main objective of this study is assessing the applicability of BioMist in removing the Odor from landfill leachate at specified environmental conditions. In order to come up with realistic solution, field observation, field measurement and experimental/sample analysis standard method is employed. The result showed that BioMist is effective in removing bad odor and improving water quality at lower concentration.

Although developed countries are currently producing large amounts of electronic waste (e-waste), the rate at which e-waste production is growing in developing countries is a major concern. The unsafe disposal of this e-waste is a growing problem and the environmental effects and human health hazards are very serious. A plan needs to be established to address this issue and in order to avoid these environmental and health consequences. This paper addresses the causes resulting in the exportation of e-waste to developing countries, the environmental and health effects resulting from this disposal, and possible mitigation strategies to address this growing environmental justice issue. Several recommendations are proposed. First, instead of trying to abolish the informal sector within these developing countries, it would be beneficial to take advantage of the collection network that the informal recycling sector has created. An incentive system will most likely be needed in order to establish the connection between the informal and formal recycling sectors. The informal recyclers will then be more willing to bring their collected e-waste to the formal facilities where it will be treated properly. Lastly, manufacturers and producers need to become more involved by implementing more successful take-back systems for their electronic devices so that they will be recycled properly at formal facilities that will mitigate the negative environmental and health impacts.

As the world’s population is growing exponentially, more and more resources are needed to meet the demand. The earth does not have an infinite amount of resources and natural reserves are on a trend towards depletion. In fact, about half of the world’s copper and other metal stocks have been mined. A solution that would help to slow the mining of virgin materials is urban mining. This is the concept of extracting valuable materials from existing infrastructure, landfills, and the dissipation of them into the environment. This would allow an increased demand for metals to be met without having to mine additional virgin materials. There are many different types and processes that can be used to collect materials, especially metals. These types include secondary mining, landfill mining, hibernation mining, dissipation mining, and in-use mining. Although there are challenges associated with urban mining, there are many benefits to continue to expand. Future research will help to improve these processes.

Waste is defined as a disposed material that is unwanted in some place or that has no value in the eyes of its producer. It is generated amply in industry, transportation, agriculture, tourism, food sector etc., in the process of production or service. These materials are distinguished from the concept “garbage” due to their economic and environmental value. It is necessary to decrease wastage at its source, and to re-gain and re-use or dispose the inevitable wastage in the manner least harmful to the environment

Economic and environmental crises appear to increasingly come from similar exogenous origins, such as market failures, and endogenous sources, such as poor management of scarce natural resources. Notably, the establishment of PNRS (National Policy of Solid Waste) in Brazil led to the development of reverse logistics (RL) practices for various economic sectors, particularly electrical and electronic equipment. This paper focuses on this question and presents a quantitative evaluation of possible economic results that could be obtained using Game Theory in a negotiation between electronic manufacturers and a cooperative of collectors/recyclers of waste electrical and electronic equipment (WEEE). This article shows that there is a possibility of eliminating market failures and improving the management of resources to obtain optimal WEEE management through the implementation of Economic Game Theory along with the Coase Theorem. The discussion highlights the importance of choosing WEEE management tools in Brazil, including criteria for potentially negotiating between economic agents associated with waste.

Participation of consumers in any domestic waste recycling program is vital for its success. Many developing countries are starting domestic waste recycling programs but little is known on the attitude or behavior of consumers toward this issue. This presents a hurdle to the success of such programs. This paper addresses consumers’ attitude and behavior toward domestic waste recycling in the United Arab Emirates (UAE). A specially tailored questionnaire was randomly distributing to a sample of one thousand consumers in UAE asking them a multitude of questions on their attitude, behavior and practices in relation to domestic waste recycling. Results indicate that only a small percentage of people actually participate in recycling even though they are aware of the deteriorating environmental quality and acknowledging that recycling preserves resources and protects the environment. Results also show that this difference between consumers’ attitude and practices might be due to some obstacles including lack of recycling bins and the long distance needed to reach those bins. Finally, some practical solutions to improve consumers’ participation in recycling in UAE are given.