Reuse is a good way to prolong product life and reduce environmental impact due to production. When the whole product cannot be reused, reuse of components might be the option. Mobile phone is a product in which technological progresses are made every year. Components of mobile phones often have high qualities. Such components may have good functionalities after the lives of the phones themselves. This paper focuses on mobile phone components and tries to find the feasibility of reuse. Because of the functionality of the component, the paper selects liquid crystal display (LCD) as the target of reuse. Firstly, disassemble experiments are carried out to clarify disassemble time and bottlenecks of dismantling. Secondly, design improvements to enhance disassemblability are discussed. Then, by comparing LCDs of mobile phones with target products, technological feasibility is examined. Finally, the paper concludes component reuse of LCD can be feasible by implementing design for disassembly.

Recently, fossil fuel depletion and global warming have become serious problems in the world. In order to solve these problems, renewable energy has attracted much attention. Here, a microalga, Euglena gracilis (E.gracilis), was focused on as a renewable biomass energy source. In our idea, E. gracilis biomass produced using nutrients in wastewater is mixed with sewage sludge, and anaerobically digested for methane recovery. It is considered that microorganisms and suspended solids in wastewater may have a negative impact against the growth of E. gracilis. Accordingly, their effect on the growth of E. gracilis was discussed in this research. Three types of culture media, supernatant fluid of wastewater, suspended solids-free wastewater, and suspended solids and microorganisms-free wastewater, were used for the cultivation test. The culturing conditions were a temperature of 25°C and photosynthetically active radiation of 98.2 μmol/(m 2 ·s). As a result, E. gracilis was able to increase in wastewater, though both microorganisms and suspended solids gave a negative influence. Since the negative effect of suspended solids was stronger than that of microorganisms, an introduction of a pre-removal process of suspended solids would be favored for the microalgal biomass production in wastewater.

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According to the widespread of EEE, run-out of certain materials so-called critical metals have become a big anxiety. Functionalities of EEE required from consumers are becoming high year by year, and such critical metals are necessary to enhance functionalities. Thus, the key of product development is to reduce the metal consumption and achieve high functionalities. In other words, high resource efficiency is the key of sustainable production. This paper proposes an index to evaluate resource efficiency of small-sized EEE. The index has value of the product based on the functionality, product reusability, and component reusability, as the numerator. And it has the total amount of environmental impact due to material consumption measured by TMR (total material requirement) minus recoverable environmental impact as the denominator. Through the case studies on mobile phones, the paper concludes that the proposed index will be useful in evaluating resource efficiency of EEE.

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