Fumitake Takahashi

Tokyo Institute of Technology | TITech ·  Department of Environmental Science and Technology

This study revealed the effects of designed infographics for waste separation and the implementation of behavioral outcomes using surveys and lab-scale experiments. The designed infographics improved the waste separation behaviors of the respondents in term of subject norm, perceived behavioral control, and intention. These influential factors were...

Owing to Minamata Convention on mercury, the final disposal of mercury in environmentally safe manners will be required. Mercury disposal in landfill sites will be one of the feasible options but its environmental risk has been strongly concerned. This study built a model including hydraulic flows of rain infiltration from the top surface, unsatura...

Minamata convention on mercury requests mercury wastes landfilling in environmentally safe manners. Owing to great difficulties to form public acceptance of landfill site construction, this study focused on emotional appraisal to mercury. The author quantitatively evaluated cognitive aversions toward mercury and other harmful/hazard-like objects li...

SO2 can noticeably impact the control of high toxic selenium emissions from flue gas by CaO. Surprisingly, our experiments showed that under certain conditions, SO2 can promote selenium capture by CaO, rather than hinder it. To elucidate the underlying mechanism, a combination of theoretical calculations and experiments was conducted. Thermodynamic...

This study aims to answer why the quality of PET bottles collected from supermarkets and public waste drop-off stations waste were contrastingly high and poor, respectively. This study developed a new contingent valuation approach which requested only simple comparison of perceptive stimuli by questionnaire respondents. This approach subsequently v...

Pyrolysis of biomass offers a promising pathway to alleviate the depletion of fossil energy. Nonetheless, the high oxygen content in biomass-derived pyrolysis oil makes bio-oil a low-quality by-product and limits its commercial application. On the other hand, oil sludge (OS) is hazardous waste from the petroleum industry and is difficult for combus...

Tar generation reduction and syngas upgrading are necessary for pyrolysis of biomass in terms of feasible applications of biomass-to-energy technology. This study investigated the effects of electron injection on pyrolysis of PP and cellulose. TG-DTA results showed that electron injection promoted pyrolysis of both PP and cellulose at lower tempera...

The mathematical modeling and the experimental study employing the pilot-scale up-draft fixed bed gasifier were carried out to investigate the effect of the electron injected air on the performance of biomass gasification. The goal of the mathematical modeling was to illustrate the temperature and chemical composition fields. Moreover, the stream f...

Municipal solid waste (MSW) composting is one of the most effective strategies for MSW management but detrimental litter such as plastic and glass debris must be discarded elsewhere. Well-segregated wastes are necessary in this context. A compost bin is a waste collection tool for source separation. To date, the deployment of compost bins for sourc...

In this research paper, potassium-activated geopolymer cubes (GeoC) fabricated from waste coal fly ash with low-temperature calcination were investigated as a water softening agent. The GeoC reduced water hardness contents by adsorbing calcium (Ca2+) and magnesium (Mg2+) ions from aqueous solutions. Batch experiments were conducted to investigate t...

Comprehensive thermochemical treatment (pyroly-sis and combustion) is considered to be an efficient method for treatment of oil sludge (OS) or utilization as a heat source. However, combustion of oil sludge char (OSC), the byproduct from OS pyrolysis, is difficult and energy-consuming due to the high ash content and low heating value. In this study...

Producing clean energy from waste biomass via pyrolysis is critical in reducing dependence on fossil fuels and alleviating their environmental impacts. Inherent potassium in low energy density coconut fibers reduces bio-oil yield and compromises bio-oil quality and the integrity of reactors within which pyrolysis occurs. The effect of consecutive h...

In this research, the thermal decomposition characteristics of cellulose, polyethylene, and their mixture with electron injected air were investigated using a laboratory-scale reactor. An electron generator with a voltage of 12 V was adopted as the key part to inject the electrons into the air in order to accelerate the thermal decomposition of the...

Efficient waste separation using recycling bins designed appropriately is promising for waste recycles. This study investigated recycling bin designs, in particular color and insert slot, and quantified perceptive preferences toward designs. This study hypothesized that design preference toward recycling bins is affected by past perceptions of recy...

Low agricultural productivity and electricity shortages continue to plague Africa. Brewer's spent grain (BSG) as a food source and precursor for biochar production via hydrothermal carbonization (HTC) can offer solutions. HTC involves the artificial coalification of biomass by direct injection of steam in a pressurized vessel to produce an upgraded...

The improvement of waste separation is of great interest in mitigating problems related to municipal solid waste (MSW) management. Trash bins are commonly used for waste separation at source. Thus, appropriate trash bin designs are promising to improve waste collection and separation performance. This study investigated the effect of trash bin desi...

Crude bio-oil was upgraded using in situ and ex situ catalysts (Ni2Fe3, ZSM-5, and Ni2Fe3/ZSM-5) in order to reduce the bio-oil oxygen content. The Ni2Fe3 catalyst powder was specifically designed for this research using materials' simulations, and it showed good activity in improving the bio-oil quality by increasing the heating value. Furthermore...

Many organizations in the world are interested in waste management problems and their potential solutions. In order to solve these problems, a Japanese venture company has developed an innovative thermal decomposer for organic wastes called ERCM (Earth-Resource-Ceramic-Machine). The ERCM reactor employs electron injected air to promote the thermal...

Porous geopolymers have been extensively developed as adsorbent materials for wastewater treatment. Display of a good mechanical strength on porous adsorbent would indicate an effective practicality in applications. In this work, we prepare geopolymeric cubes from coal fly ash by potassium-activation at different ratios of silicate: hydroxide, all...

The influence of inherent tire char ash during co-gasification with coconut hydrochar prepared at different intensities was investigated by thermogravimetric analysis to ascertain the extent to which synergistic interaction, reactivity, and activation energy reduction were altered. High-ash tire tread (TT) and low-ash sidewall (SW) both exhibited e...

Coal fly ash (FA) utilization as water retention agent to ameliorate soil is attractive in arid/semi-arid area. FA amendment was expected to make void pore networks in soil better for water retention. The purpose of this study is to investigate FA amendment effect on weight-based water holding capacity (WHC) and evaporation mitigation capacity (EMC...

Micro-scale correlation analysis was applied to estimate metal speciation and the matrix in municipal solid waste incineration (MSWI) fly ash in this study. The results showed that dominant metal speciation and the bonding states with fly ash matrix are different in individual fly ash particle. Micro-scale correlation analysis also suggests metal b...

Although municipal solid waste incineration fly ash are fine particles and a priori considered as homogeneous, they have complicated structures inside their bodies. This study quantitatively investigated two categories of heterogeneity of fly ash produced from a fluidized bed combustor. They are the heterogeneity of a single fly ash particle body (...

The heterogeneity of waste tyre pyrolytic char associated with ash composition and distribution is explored to understand the effect of ash on gasification. In this paper, high-ash tyre tread (TT) and low-ash sidewall (SW) were separated to study gasification kinetics and the influence of ash on char physico-chemical morphological evolution during...

Hydrothermal carbonization (HTC) is a promising technology for converting high moisture municipal solid waste (MSW) to a safe low-chlorine hydrochar. The key objective is to assess the economic viability of an HTC based MSW management system in Zimbabwe. Previous studies have only used deterministic estimates of hydrochar production costs disregard...

This study investigated the effects of setting conditions of trash bins on waste collection, separation efficiency, and incorrect disposal. Tested trash bins are for combustible wastes, PET bottles, cans, and glass bottles. Monitoring results were analyzed by statistical tests to distinguish real effects and experimental errors. The distance to tra...

Many municipalities in Japan have collected PET bottles as recyclable waste since 1980s. When caps are removed from bottles, it reduces collection and transportation costs because bottles can be easily compressed by collection trucks. However, PET bottles collected from recycling bins are usually capped and include other materials. This study desig...

Internet video sharing has been used by scholars for two main purposes. First, it is for informal scholarly communication including teaching and academic conferences. Second, it is for engagement tool by contemporary society. Renewable energy technology has also been utilizing internet video sharing technology for those purposes. It is a promotiona...

Banana residues remain untapped for substantial thermochemical energy conversion. In this study, lab-scale production of hydrochar from banana leaves (BL) by hydrothermal treatment (HT) for solid fuel combustion was investigated. The HT was conducted at 180, 200 and 220 °C for 30 min, resulting in an energy yield of up to 94.0%. The fuel properties...

Elemental mercury (Hg0) is widely used by Artisanal and small-scale gold miners (ASGMs) to extract gold from ore. Due to the unavailability of appropriate waste disposal facilities, Hg0-rich amalgamation tailings are often discharged into nearby aquatic systems where the Hg0 droplets settle in bottom sediment and sediment-water interfaces. Hg0 diss...

Conventional methods to produce sludge activated carbon require high-energy due to high ‎moisture content and poor dewaterability of the wet sludge. Recently hydrothermal ‎carbonization (HTC) has been emerged as a promising thermo-chemical wet biowaste ‎conversion technology for the valorization by converting these precursors into high value-‎added...

Globally, Landfill is still the most common method for waste disposal. In most developing countries, the landfill has received municipal waste without going through any separation, even intermediate treatment. Landfill sites have become hidden treasure full of resources. Jatibarang Landfill in Semarang City, Indonesia has been operated since 1992 a...

Public understanding on biomass energy has been considered as an important factor in the implementation of biomass energy technology. However, there have been a few literatures that have demonstrated public understandability and reaction toward information on the utilization of biomass waste into energy especially for electricity generation. This p...

This study firstly investigated elemental heterogeneity of municipal solid waste incineration (MSWI) fly ash particles. Two types of heterogeneities were measured quantitatively focusing on three structural components of fly ash particles. They are internal heterogeneity of individual fly ash particles (intra-particle heterogeneity) and inter-parti...

The vast increase of municipal solid waste (MSW) generated in Zimbabwe coupled with a severe energy crisis have made waste-to-energy technology more attractive and necessary. Coal-alternative solid fuel production from MSW though hydrothermal carbonization can play a critical role to improve both waste management and energy supply. Moreover, MSW co...

There is no proper intermediate treatment for municipal solid waste in Indonesia before dumped in a landfill. Most of the Indonesian dumpsite already over capacity and need intensive treatment. This study examines Jatibarang Dumpsite in Semarang City, Indonesia to assess the material recovery potential for solid fuel. After excavation obtained mate...

Brewer’s spent grain (BSG) has the potential to contribute to the supply of energy in Africa, as concern for clean and sustainable energy grows. The synthesis of biocoal from BSG via an artificial coalification process, hydrothermal carbonization (HTC), is preferred amongst other thermal conversion techniques as HTC is capable of handling high mois...

Thermochemical waste to energy technology could efficiently tackle waste management problem, but it could emit dangerous pollutant if the quality of the feedstock is bad and standard operating condition was not met. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) methodology was used to assess the quality of refuse material for solid fuel...

Application of acid in HTC process has been confirmed to have effect on hydrochar properties related to its adsorption capacity. Woody materials (tree branches) were used to investigate the relation of nitric acid addition in HTC process on the hydrochar surface properties and its adsorption mechanism toward cadmium in water solution. Tree branches...

Hydrochar prepared from the hydrothermal liquefaction of microalgae is characterized and investigated for copper removal from aqueous solution. Two hydrochars were prepared at 210 °C (HD210) and 250 °C (HD250). The effect of the initial solution pH, the initial Cu(II) concentration, the contact time, and the temperature will be investigated. Accord...

Geological site owned by Indonesia is very diverse, so it should be optimally utilized. In a geo-heritage or geo-park region has some geological sites. Parangtritis area is a famous as one of the beach tourism in Yogyakarta. Parangtritis region has morphology of coastal plain at the south, karst hills in the east, intrusion hills in the north and a...

DI Yogyakarta is the largest student and tourism city in Indonesia that produces 2,953 tons of waste per day. Increasing waste generation is not matched with adequate landfill sites. Landfill mining and utilization of excavated waste is a method that can be used to overcome the problems in the landfill. Combustible waste could be used as renewable...

Indonesia has the largest geothermal potential in the world. However, the utilization has not optimal yet. Wayang Windu Power Plant is two phase geothermal system, where 100% of the separated brine is reinjected through an injection well 14 km away from the plant. The energy from the brine can be utilized before reinjection, such as for direct use,...

We investigated the effect of ultrasonic pretreatment on the bio-oil yield and heating value in the low-temperature hydrothermal liquefaction (HTL) of microalgae. HTL is one of the thermochemical processes for bio-oil production. However, the high pressure of the process is one of the main challenges for commercialization. On the other hand, a decr...

Preparation of sludge-based activated carbon (SBAC) required to the carbonization step followed by the activation process. The conventional carbonization method such as pyrolysis needs to use high energy due to high moisture and poor water dewaterability of wet sludge. Recently, the hydrothermal carbonization (HTC) as a promising wet biomass conver...

Impacts of secondary generated minerals on mineralogical and physical immobilization of toxic elements were investigated for chelate-treated air pollution control (APC) fly ash of a municipal solid waste incinerator. Scanning electron microscope (SEM) observation showed that ettringite was generated after the moistening treatment with/without chela...

Landfilling remains the predominant component in the waste management hierarchy of most developing nations. The adoption of emerging waste management technologies and the use of recycling or composting is still in its infancy. Among several inadequacies of current waste management practices in Zimbabwe is the absence of sanitary disposal of municip...

Artisanal and Small-scale Gold Mining (ASGM) activities employing the mercury amal-gamationtechnique have resulted in a significant drop in the quality of water from Ngwabalozi River, Zimbabwe. Mercury levels as high as 0.31 mg L-1have been reported in its waters and the low river pH (pH 3) favors proliferation of microorganisms responsible for met...

The environmental concerns for treating cyanide-containing wastewater via adsorption technology has been advancing which resulting in the need for a robust yet simple method. Synthetic zeolite was used as a suitable adsorbent for cyanide removal due to its excellent surface properties. In this study, the modification of zeolite was made by iron dop...

Since the early 90s, many researchers have tried to improve the life cycle of Tetra Pak products by improving the recycling process for Tetra Pak waste. In this paper, a novel method is proposed in which a hydrothermal process is utilized to produce solid fuel and recover the aluminum and polyethylene composites. The experiment was done at the thre...

Crop residues and animal dung can contribute a significant portion to the biomass available for conversion to biofuels in Zimbabwe. This paper will extend a quantitative methodology involving the use of probability distributions to rigorously address uncertainty in the quantification of this biomass. The results of 100 000 Monte Carlo simulations u...

Improving public understanding and awareness is often considered as one of key factor on the waste-to-energy implementation. In order to improve awareness on plastic separation from household waste, an education and public outreach activity has been initiated by involving the development of pyrolysis technology for producing liquid oil. The technol...

This paper investigated the feasibility of a low-cost and highly effective tar removal technique using venturi oil scrubber enhancing the absorption surface area by producing microbubbles for tar removal in biomass pyrolysis/gasification processes. The basic experiment was carried out by utilizing a laboratory-scale fixed bed pyrolyzer, and then th...

Bio-based fertilizers are currently gaining interest as a method for reducing the use of chemical fertilizers and as a means for safe disposal of biomass waste. Feathers, which are an abundantly available biomass and have a high N content, are a potential source of fertilizer nutrients. In this study, chicken feathers were subjected to hydrothermal...

In this study, Tetra Brik from Tetra Pak Company was used to produce solid fuel. Tetra Brik consists of paper, LDPE, and Aluminum arranged in 6 different layers. Aluminum should be recovered to obtain high-quality solid fuel. Hydrothermal treatment was used to separate aluminum from the solid fuel. Temperature and time were controlled and observed...

To improve the life cycle of Tetra Pak product, many researchers has tried to improve the recycling process of Tetra Pak waste since the early 90s. In this paper, a novel method by utilizing the hydrothermal process to produces solid fuel and recover the composite of aluminum and polyethylene. The experiment was done in the three level variations o...

Low public understanding on biomass energy is suspected as one of causes of slow progress of biomass energy application. This paper presents an adoption of rapid appraisal method for comprehension assessment of online information of biomass energy. The method consists of quantitative measure of written information by a standardized readability test...

In this study, Tetra Brik from Tetra Pak Company was used to produce solid fuel. Tetra Brik consists of paper, LDPE, and Aluminum arranged in 6 different layers. Aluminum should be recovered to obtain high-quality solid fuel. Hydrothermal treatment was used to separate aluminum from the solid fuel. Temperature and time were controlled and observed...

The major challenge of biomass gasification technologies is the control of the tar concentration to acceptable level for each downstream application in order to prevent clogging and fouling problems. Low cost and high efficiency tar removal by combining a venturi scrubber and absorbent regeneration was proposed in order to enhance and maintain the...

Waste management contributes to renewable energy such as biodiesel production from processes of various types of biomass including vegetable oils, animal fats, and waste of edible oil. Successful waste management effort is influenced by people concern about benefit of waste management including for renewable energy from biomass. It involves their u...

In this study, Newlands coal, spirulina microalgae samples and mixtures of them were gasified in a fixed-bed downdraft reactor by CO2 at the atmospheric pressure and in the temperature range of 950-1000 ºC. The effects of the reaction temperature, the CO2 partial pressure and the blending ratio on the syngas yield were studied. Results showed that...

Recently, biomass utilization is regarded as a promising waste-to-energy technology, especially pyrolysis and gasification. However, for implementing in advanced applications such as internal combustion engines, the cleanliness of synthesis gas should be highly taken into consideration because tar contained in synthesis gas causes blocking and foul...

A new method to analyze metal species in municipal solid waste incineration (MSWI) fly ash employing correlation analysis of elemental distribution line profiles was investigated. Titanium species in chelatetreated MSWI fly ash were estimated by this method. After treatments of fly ash by leaching experiments with different solvents, it showed that...

Simulation using a mercury environmental fate model is useful and usually required to estimate mercury environmental risk. Because environmental fate of mercury species depends on physical, chemical, biological reactions, models include many parameters. In addition, some parameters like biomagnification factor are reported in several orders of magn...

In this study, Newlands coal char and spirulina algae char were prepared separately in a fixed bed reactor with a pyrolysis temperature of 1000 ºC. The isothermal CO2 co-gasification experiment was done using a thermogravimetric analyzer in the temperature range of 800–1000 ºC. The volumetric model (VM), the shrinking core model (SCM), the random p...

This study aimed to evaluate the life cycle energy consumption of microalgae-to-biodiesel with low temperature hydrothermal treatment (HTT) as an oil extraction method. The scope covered all stages in the life cycle from microalgae cultivation, microalgae harvesting, HTT, and transesterification. In order to clarify the energy consumption and the m...

Bottom ash is an inevitable by-product from municipal solid waste (MSW) incineration plants. Recycling it as additives for cement production is a promising disposal method. However, the heavy metals and chlorine are the main limiting factors because of the potential environmental risks and corrosion of cement kilns. Therefore, investigating heavy m...

The pyrolysis of oil sludge with addition of oil sludge ash, Al2O3, Fe2O3, CaO and SiO2 was carried out under inert condition employing a stirred tank reactor to investigate the catalytic effect of metal oxides on the oil product quality. Thermogravimetric scale experiments were conducted for searching the optimal reaction temperature. The reaction...

Renewable energy-related information in the Indonesian language (Bahasa Indonesia) is nowadays easily accessible on the internet and seeking information from the internet has become the second highest activity of Indonesian netizens. This paper aims to examine the readability of biomass energy-related information that is retrieved from the internet...

A pyrolysis study of oil sludge with and without oil sludge ash and quartz sand as solid heat carriers was conducted using a laboratory-scale reactor and thermogravimetric analyzer. The effects of the pyrolysis temperature and solid heat carrier on the product distribution and oil quality were investigated. The results of the oil sludge ash additio...