Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research)
Online ISSN : 2185-6648
ISSN-L : 2185-6648
Volume 75 , Issue 6
Showing 1-29 articles out of 29 articles from the selected issue
Journal of Environmental Systems Research, Vol.47
  • Yusuke NAKATANI, Anna MIYANISHI, Shuzo NISHIDA
    2019 Volume 75 Issue 6 Pages II_1-II_6
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     To maintain a healthy circulation system in coastal areas, the inflow load balance of nutrients including nitrogen, phosphorus, and silicon must be properly controlled. This study collects and analyzes the amount of water intake and water quality data of water purification plants, which intake groundwater in the Yodo River Basin, and calculates the amount of nutrients transported via groundwater intake to quantitatively evaluate the nutrient dynamics in the basin.

     Thus, the water quality distribution characteristics of the groundwater differed among water quality items, and silicon showed high concentrations in deep wells in the lower Yodo River Basin. Additionally, 10%–15% of the amount of silicon transported through the river under ordinary water level conditions was derived from the groundwater intake at the water purification plants, which had a considerable influence on the basin-scale transport.

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  • Yotaro MITSUMATA, Seiji HASHIMOTO
    2019 Volume 75 Issue 6 Pages II_7-II_15
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     It has been pointed out that there is the significant amount of stocks of polyvinyl chloride (PVC) in our society because PVC products have long lifetime. These stocks can be seen as potential secondary resources. This study estimated Japan’s secondary PVC reserves, which was the amount of economically recyclable secondary resources out of PVC stocks in our society. The following conclusions were drawn: (1) the amount of PVC stocks as products was estimated 24 million tons in 2016 and the stocks were saturated recently because of the decrease in demand and increase in discard; (2) the amount of secondary PVC reserves were estimated 8,737 thousand tons, which corresponded to about 9 years of demand in 2016; (3) according to the secondary resource classification, secondary reserves that were supplied in a year were estimated 207 kilotons, which corresponded to about 0.2 times of demand in 2016, and the amount of PVC waste in managed landfill sites was almost equivalent to the amount of PVC stocks as products in our society.

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  • Yuki HIRUTA, Lu GAO, Shuichi ASHINA
    2019 Volume 75 Issue 6 Pages II_17-II_27
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Highly fluctuating electricity demand causes an increase in the cost of electricity supply and the consumption of fossil fuel. To find countermeasures for global warming and ways to adapt to the warming of the urban thermal environment, it is important to clarify the relationship between climatic conditions and the hourly electricity demand. We constructed regression models that estimate power consumption based on various factors such as people's activities and multiple climatic conditions in order to understand the sensitivity of hourly electricity power consumption to temperature and humidity. Through the simulation by the model built, it was found that the influence of humidity is large in the summer: The higher humidity lowers the balance point temperature and increases the rate of power consumption per 1 °C.

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  • Taira OZAKI, Hiroki ABE
    2019 Volume 75 Issue 6 Pages II_29-II_37
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The effects of climate change are already being experienced globally through more extreme weather events and the resulting impacts on people’s lives, health and wellbeing. Especially, growing proportions of older people are increasingly exposed to risks which are vulnerable to the impacts of climate change. It is necessary to provide opportunities and places for elderly people to go out to urban space more actively for health promotion. The Health Promotion Park and Meiwaike Park are neighborhood park located in Suita City and Settsu City, respectively. The purpose of this study is to clarify 1) the difference in utilization characteristics of Health Promotion Park and Meiwaike Park, 2) the relationship between exercise and heat environment in the Health Promotion Park. As a result, the main users of Meiwaike Park on weekday evenings are children, while the main users of the Health Promotion Park, including the evening of weekdays, are adults and the elderly. Many users are exercising with health playground equipment in Health Promotion Park. It was clarified that about 40% of users exercise at high risk of heatstroke.

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  • Takanori MATSUI, Ayako KAWAWAKE, Asako IWAMI, Naoki MASUHARA, Takashi ...
    2019 Volume 75 Issue 6 Pages II_39-II_47
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     To revieal the nexus of goals, targets and indicators of SDGs (Sustainable Development Goals) for achieving SDGs by 2030, we conducted a network and cluster analysis in Japanese prefecture scale using SDGs indicators, and co-occurence analysis of SDGs targets by text mining the SDGs future-cities’ planning in city scale. Based on our analytical experience of SDGs nexus, we proposed a research agenda for better progressing SDGs nexus researches; (1) visualizing the nexus of Japanese SDGs action plans scientifically and provide them to all stakeholders, (2) forming a knowledge transfer platform consists of tempospatially high resolved SDGs indicators and tailor-made recommendation systems, (3) developing tempospatially seamless SDGs indicators tracking system with bigdata and data science technology, (4) designing the lookup-logic for very easily convering conventional strategic plans to SDGs-oriented plans, (5) establishing open science platform for SDGs nexus researches by Goal 17: Partnership for the Goals.

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  • Kazuma MURAKAMI
    2019 Volume 75 Issue 6 Pages II_49-II_57
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     This study examined the influence of the relationship with nearby residents on the decision-making processes of green curtain implementation by using structural equation modeling with questionnaire data from residents. The proposed model shows that the gratification derived from cultivation and the shading and cooling effects of green curtains increase residents’ willingness to implement green curtains next summer, while the cost awareness suppresses this willingness next summer. Furthermore, the relationship with nearby residents enhances the gratification derived from cultivation and the shielding and cooling effects but does not affect cost awareness. In the group wherein green curtains have not been implemented this summer, the gratification gained from cultivation increases their willingness to implement them next summer. In the implementation group, the shading and cooling effects increase this willingness, while the cost awareness suppresses the willingness, and the effects of shading and cooling effects dominate the effects of cost awareness.

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  • Noriaki KONDO, Katsura NAKANO, Katsuya TANAKA
    2019 Volume 75 Issue 6 Pages II_59-II_67
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     This study clarified the effect of the existence of companion animals on the evaluation of the place of residence and participation in community activities. Evaluation of the residence is at risk of bustling, environmental management and disasters, Participation in the community activities is bridging SC and bonding SC. It became clear in the SEM model that living with a companion animal or a child under the age of 15 promotes health, enhances participation in community activities, and has the effect of forming a bridging SC.

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  • Noki HAYASHI, Atsushi FUJIYAMA, Toru MATSUMOTO
    2019 Volume 75 Issue 6 Pages II_69-II_76
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The spread and expansion of waste power generation, which is a decentralized energy and stable supplier of electricity, is expected. By networking waste power generation, it is expected to reduce the amount of electricity purchased from the former general electricity utilities, the CO2 reduction effect, and the virtuous circle of the regional economy.

     The economic and environmental aspects of networking and retailing were evaluated for three waste pwer generation faculities located in Kitakyushu city, and their effectiveness was confirmed. Furthermore, for the legal inspection period of waste power generation, the optimization calculation of the scheduling that maximizes the power sales was performed, and the effectiveness was verified.

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  • Dedi Abdul HADI, Toru MATSUMOTO
    2019 Volume 75 Issue 6 Pages II_77-II_85
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Trade has been agreed as one of the economic growth factors because of its impact to several economic sectors, such as investment and information technology development; however, it also has an effect on the environment. The more goods traded the more economic activity and the bigger the impact on the environment. The preferential trade agreements have been encouraged to increase the volume of trade between the parties involved. Currently, Indonesia is involved in several free trade agreements, and it which results in a growing volume of imported goods to be used in the economic activities as reflected in the Input-Output Table. This paper attempts to analyze the impact of the implementation of preferential trade agreement schemes in Indonesia by using the Environmentally Extended Input-Output Analysis method developed by Wassily Leontif. The final calculation shows the significance of carbon emissions released from agriculture sectors.

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  • Ryusuke OTANI, Takao YAMADA, Akifumi NAKAO, Syuiti YAMAMOTO, Yugo YAMA ...
    2019 Volume 75 Issue 6 Pages II_87-II_99
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     In this study, an analysis of GHG reduction and feasibility at the thermoselect gasification and reforming furnace was carried out in order to clarify possible technologies applicable in clean steage Co., Ltd. Here we estimated possible amount of GHG reduction based on heat balance analysis. We also examined cost and benefit accompanied by implementation of the technologies. As a result, it was revealed that gas engine gave advantages in both GHG reduction and business feasibility at the thermoselect gasification and reforming furnace.

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  • Mineo TSURUMAKI, Seigo HASHIMOTO, Yugo YAMAMOTO, Noboru YOSHIDA, Shunk ...
    2019 Volume 75 Issue 6 Pages II_101-II_112
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The Great East Japan Earthquake has affected many human waste treatment plants causing serious problems in the treatment of night soil and sludge. Therefore, it is necessary to consider the way of wide-area support for Nankai Trough earthquake that may be caused extensive damage. However, the possibility of wide area support in such a situation has not been studied so far. In this study, Wakayama Prefecture was considered as a target area, and quantitative and qualitative changes in human waste and sludge after the earthquake, and the necessity of wide area treatment corresponding to the situation were examined. The amount of human waste and sludge discharged during the period until 120 days after the disaster was examined. As a result, it was clear that it cannot be treated only by the facilities in the prefecture and support from the Kinki area in a wider area is needed. It was also made clear that there is a period in which 70% or more consumption of the margin of treatment are required and that there is a need for coordination with support for other damaged areas.

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  • Toyohiko NAKAKUBO, Mutsumi SUTO, Saki SANO, Masahiro OTAKI
    2019 Volume 75 Issue 6 Pages II_113-II_123
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The purpose of this study is systematizing emergency water supply planning concepts where a liver's adaptability to disaster-affected environment is included as a planning factor. Toward quantifying the adaptability, we designed water-related living activities based on different types of quality of life (QOL) standards for each end-use. Through the questionnaire survey, the percentages of selected activities in each enduse and in each term were aggregated, and then we set water demand rates and disaster supplies demand rates. The next step was estimating demands for water and disaster supplies in each term following a water failure under a case study targeted for a scenario earthquake: Southern Ibaraki Prefecture Earthquake. Based on the estimated results, we considered the emergency water supply plan collaborated with preparedness of disaster supplies.

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  • Taira OZAKI, Ryoya IKEDA
    2019 Volume 75 Issue 6 Pages II_125-II_134
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Recently, pluvial flood disasters will increase due to the influence of climate change caused by global warming in Japan. Japan’s financial condition is not good. Due to these constraints, it is necessary to develop a method to determine the priority area for flood control. According to IPCC’s Fifth Assessment Report, Risk of climate-related impacts results from the interaction of climate-related hazards with the vulnerability and exposure of human and natural systems. In this study, we develop a method to assess the urban flood risk based on the IPCC’s risk concept, and discuss its effectiveness and limitations.

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  • Riku OYAMA, Tatsuro SATO, Hidetaka ICHIYANAGI, Hironori HAYASHI, Tomok ...
    2019 Volume 75 Issue 6 Pages II_135-II_141
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Micro-hydropower, as a hopeful decentralised renewable energy, is expected to be introduced in various parts of Japan. Micro-hydropower has been considered to have a small environmental load, but since a water abstraction reach exists, it is necessary to evaluate the impact on the river ecosystem correctly. In this study, the influence of water abstraction by micro hydropower was quantitatively evaluated for each habitat type of mountain streams using benthos as a sensitive index. As a result of field investigation, in the Kaji River, the influence on the benthic animal population, the number of taxonomic groups, and the community structure by water abstraction were not statistically recognised in all mountain stream habitats. In the Kamo River, the number of benthic animals and the number of taxonomic groups decreased in the water abstraction reach in some habitats, including step, cascade, rapid and stagnation.

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  • Kenta FUKUSAKI, Fumitaka MESAKI, Yo MIYAKE
    2019 Volume 75 Issue 6 Pages II_143-II_149
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     This study aimed to clarify the response of invertebrate assemblages to flood disturbance in lowland stream s. We established 12 study sites in the Dogo Plain, Ehime Prefecture, southwestern Japan, and conducted survey on stream invertebrates and habitat characteristics before and after a flood event. As a result, while invertebrate density decreased in all study sites, taxon richess appeared to increase in three sites after the flood event. Our community structure analysis showed that tolerant taxa originally dominated in those sites, but intolerant taxa increased after the flooding. The relationship between catchment feature and the change rate of taxon richness implied that the increase in taxon richness can be attributed to new colonization by intolerant taxa during the flood from upstream, clear water segment located in mountain area.

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  • Kenshi BABA, Asako IWAMI, Eri AMANUMA
    2019 Volume 75 Issue 6 Pages II_151-II_159
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     We applied the online deliberation experiment to the issue of climate change adaptation in disaster risk reduction (DRR) and analyzed the change of the cognition and preference of the experiment participants who live in disaster affected areas by questionnaire data of before and after deliberation and by text mining of discourse. The main results are as follows; i) during the deliberation, a wide range of topics were discussed and converged to adaptation options over time, ii) health damage and wind and flood damage were rated high before and after the experiment as climate change risk, and especially water shortage and deterioration of water was got rated high after the experiment, and iii) the self-help measures among climate change adaptation in DRR were got understanding of the experiment participants though transformative measures including evacuation for a long time faced negative responses.

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  • Motoko KOSUGI, Kenshi BABA, Mitsuru TANAKA
    2019 Volume 75 Issue 6 Pages II_161-II_167
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The aim of this study is to consider effective information provision measures to promote understanding and action on climate change risk. We conducted a focus group interview for the purpose of clarify the contents of the providing information according to each target who are divided by the attitude toward global warming. As a result, it shown that people who are realize and warn of the risk of global warming have scientific knowledge on the mechanism and effects of global warming, however they doesn’t know about mitigation and adaptation measures. Therefore, it is important to provid information about the connection of effect and countermeasures. Skeptical people obtain skeptical information on global warming from non-conventional media and tools, which might disrupts understanding of global warming and supresses countermeasures. The importance of providing scientific knowledge from reliable sources for them was suggested. People with low interest do not realize global warming and it is difficult for them to feel reality of global warming by information provision. It was suggested that it is important to consider the policy to promote action by providing informaiton about adaptation measures as individual response to effects such as heat and flood.

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  • Yusuke UENO, Yuka MAEDA, Keiichi HASEGAWA, Shinsuke NANZAKI, Shouko FU ...
    2019 Volume 75 Issue 6 Pages II_169-II_176
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     In Japan, with the age of population decline, vacant land and vacant houses are increasing throughout the country. Therefore, when considering future urban planning, there is a need for measures to effectively utilize vacant land as green infrastructure and to convert it into a sustainable and harmonious city. However, the needs of citizens are likely to differ depending on age and lifestyle. In this study, we conducted a large-scale questionnaire survey in Moriya city, Ibaraki prefecture, and clarified the difference in the public's awareness of green space according to the attributes of the respondents. As a result of this study, it was found that the needs for green space are different depending on the age, parenting experience and household income.

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  • Keisuke TAKAHASHI, Kazuei ISHI, Hirohide AGA, Masahiro SATO, Satoru OC ...
    2019 Volume 75 Issue 6 Pages II_177-II_188
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Long-term waste management systems where energy recovered from waste is utilized in regional recycling symbiosis and/or new value is created are required. This study examined waste management scenarios from long-term point of view, focusing on Furano living area which has already shared waste treatment facilities. As a result, for burnable waste, if there is an enough heat demand, a RDF process is effective in terms of cost, energy recovery and GHG emission reduction, but if a heat demand is not expected, consignment to an incineration facility with power generation is effective even considering the increase in the transportation distance. For kitchen waste, the introduction of methane fermentation increases costs but is effective in terms of energy and GHG.

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  • Hafizhul KHAIR, Indriyani RACHMAN, Toru MATSUMOTO
    2019 Volume 75 Issue 6 Pages II_189-II_196
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Indonesia initiated “Waste-free Indonesia 2020” campaign, one of the implementations to reach the goal is through solid waste bank programs. The Government encourages the growth of solid waste banks nationwide. Adopting a bank system, the solid waste bank is a community-based activity to facilitate people in solid waste recycling. With this system, the community deposits waste and earns money. The objective of this study is to assess the environment and the economy of solid waste bank activities as a part of municipal solid waste management in Indonesia. The study analyses the effectiveness of solid waste bank management to become environmentally and economically. This study uses a life cycle assessment method to estimate the environmental impact by using CO2 as an evaluation indicator. The economic performance was determined by measuring the cost and benefit of the solid waste bank activity. Researchers expect that the solid waste bank is an environmentally friendly and low-cost activity to enhance the recycling rate in Indonesia. This study found that solid waste bank could save 37.73 tonnes CO2 eq. per year and contribute 7 million rupiahs per year as external benefits. The results of this study are expected to help the waste bank to improve its system and can be used as necessary information for policymakers to recognize and integrate waste banks into municipal solid waste management systems.

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  • Shingo ADACHI, Yasuhiro ARAI, Akira KOIZUMI, Shinsuke TAKAHASHI, Takes ...
    2019 Volume 75 Issue 6 Pages II_197-II_208
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     In water systems, service reservoirs enable transmission flows to be smoothed by buffering temporal variation of water usage with changing their levels. Skilled operators balance between the variation ranges of levels of service reservoirs and the smoothing of transmission flows. In this study, we propose an operation scheduling method which replicates the balance by learning from the operation records. We analyzed the level records of service reservoirs in a real system and described the effect of characteristics of the reservoirs on the histograms and the quantiles of the records. Based on the analysis, we formulated an operation scheduling model of intake and distribution pumps which minimizes deviations of reservoir levels from their usual ranges, computed by quantiles of level records of service reservoirs. In a case study, the proposed method computed operation schedules which replicated the balance between the variation ranges of levels of service reservoirs and the smoothing of flows exhibited in the operation records. In addition, it is suggested that the proposed method could reduce the violation of a service reservoir compared with current operators.

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  • Kohei HASEGAWA, Yasuhiro ARAI, Akira KOIZUMI
    2019 Volume 75 Issue 6 Pages II_209-II_218
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Water Distribution Systems (WDS) are designed with some surplus capacity to meet firefighting needs as well as daily water supply. However, water companies have often overpaid the cost needed for firefighting capacity despite official specification because there are no theoretical bases to clarify cost allocation between water companies and fire departments. To better quantify additional costs derived from firefighting capacity in WDS design, this paper proposes Island Model Genetic Algorithm to internalize hydraulic simulation under fire flow. The proposed model is applied to a realistic gravity-fed WDS as a numerical experiment. The results showed that the proposed model can design WDS more accurately measuring firefighting capacity and cost allocation in a reasonable time with the support of parallelization. The generalized and rapid model proposed in this study is expected to be further applied to various WDSs.

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  • Youngwook NAM, Yasunari FUJIMOTO, Yasuhiro ARAI, Takaharu KUNIZANE, Ak ...
    2019 Volume 75 Issue 6 Pages II_219-II_230
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Leakage of water pipelines lead to regional water reduction and outages, secondary damage such as water supply shortage and road collapse. Monitoring using sensors and networks is expected for on-line leak detection, because it enables automatic measurement and transmission to the server. In this study, we focus on the difference of deterministic properties between the background noise and the water leak sound. Furthermore, we used chaos analysis to determine background noise and water leak sound by quantifying the deterministic property, and demonstrate about the difference depending on the pipe type also. The data used in the experiment are the actual background noise and water leak sound measured on an outdoor test course. In order to visualize the characteristics of the water leak sound, it is necessary to convert time series data into geometrical data. After checking whether it is a stochastic data or not, the sound is determined based on the strength of the deterministic property. From the result, the deterministic property of the leak sound is stronger than the background noise, it is clarified that the deterministic property is a useful index for leak detection.

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  • Takaharu KUNIZANE, Akira KOIZUMI, Yasuhiro ARAI, Kodai ARAI, Masakazu ...
    2019 Volume 75 Issue 6 Pages II_231-II_238
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     The ageing of the water distribution systems has recently become a significant issue in Japan. Majority of the water pipelines are buried underground and cannot be visually inspected, which increases the difficulty of pipeline maintenance. The poor pipeline conditions only become apparent after the occurrence of a water quality incident or leakage. Therefore, in-pipe endoscope cameras have attracted considerable attention because they are one of the few non-excavation methods that can be used to diagnose the condition of a buried pipeline directly without cutting off the water supply

     In this study, we analysed the data obtained from the in-pipe camera inspections conducted over the past 15 years, including samples of both the ductile iron pipes and the cast iron pipes. We verified the images of the pipe interiors from the in-pipe camera inspections and assigned scores of S through D to each pipeline with respect to the following five categories: rust status; adhesion of substances to the inner surface; status of the inner coating; sediment and suspended matter. We further classified the pipelines with scores of S and A as ‘Good’ group and those with scores of C and D as ‘Bad’ group.

     We conducted factor analysis using Hayashi’s second method of quantification to clarify the relations among the deterioration in the pipe, the evaluation scores, the basic information about the pipeline and the water quality data. Our analysis revealed a very high rate of accurate classification (82.1%). Based on the category score, the status of the inner coating was observed to have the most influence on the deterioration of the pipe; we also confirmed that the water quality factors, such as the manganese concentration in raw water and the pH as well as the hardness of the purified water, affected the pipe deterioration.

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  • Yoshihiro YOKOYAMA, Akihiko FUJII, Yuuya GOTOU, Yuuichi MOCHIZUKI, Tad ...
    2019 Volume 75 Issue 6 Pages II_239-II_246
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     We studied the effect of sewerage treatment water discharge that let processing relieve on nutrient such as dissolved inorganic nitrogen (DIN) concentrations in the Nori cultivation grounds, Ariake Bay, Japan. We examined the contribution of the DIN concentrations in the Nori cultivation grounds discharged from sewerage treatment plants by using a mass transfer model that considered advection and diffusion.

     As a result, we observed an increase in the DIN supply in the Nori cultivation grounds caused by relieving the sewerage treatment in front of these grounds during the winter season. We particularly calculated that the contribution ratio of the DIN concentrations rose from 10% to 20% during the winter season, although there were little rain and limited supply of DIN loads from local rivers. Furthermore, we found that the DIN concentration of the Nori cultivation grounds, which is located in the south of Saga Prefecture, rose by 4% owing to sewerage treatment water discharge, which flowed into the western sea area in Saga Prefecture.

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  • Takahiro MICHIURA, Akifumi NAKAO, Yugo YAMAMOTO, Noboru YOSHIDA
    2019 Volume 75 Issue 6 Pages II_247-II_259
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     In this study, GHG reduction and business feasibility were evaluated in consideration of selecting a heat source for sewage sludge fuelization, as a case study in Kitakyushu city. Here, proposed 4 heat sources for drying sewage sludge were the followings: digestion gas (case1); waste heat in a cement factory (case2); combustion heat of municipal waste (case3); and biogas from municipal waste (case4). As a result, it was revealed that case2 brought about the greatest GHG reduction and business feasibility. In addition, several important viewpoints were discussed in utilizing heat sources and renewable energy derived from sewage sludge.

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  • Yuta NASU, Akifumi NAKAO, Syuiti YAMAMOTO, Yugo YAMAMOTO, Mineo TSURUM ...
    2019 Volume 75 Issue 6 Pages II_261-II_271
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     This research aims to examine and contribute relevant information for future municipal disaster waste disposal plans. To this end, we collected the domestic waste disposal plans in each prefecture and examined the per unit generation rate (PUGR) and estimation methods used in each plan. Five PUGRs were observed and their characteristics were identified. Some local governments were also revealed to be inconsistent in the use of assumed disasters and/or the intended purposes of the PUGRs. Furthermore, we estimated the amount of disaster waste generation using the PUGR of the Disaster Waste Disposal Guidelines for Wakayama Prefecture as a case study. We examined the influence of PUGR on each item in the existing plan of the Wakayama Prefecture. In conclusion, we discussed the importance and influence of PUGRs on waste disposal plans.

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  • Ryosuke DOAMI, Takao YAMADA, Akifumi NAKAO, Syuiti YAMAMOTO, Noboru YO ...
    2019 Volume 75 Issue 6 Pages II_273-II_284
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     This study aimed to evaluate feasibility of facility renewal for aging municipal waste incineration plants under declining population, as a case study at Sensyu area in Osaka prefecture. In this study, we considered various driving factors, such as changes in charged cost to the local governments, uncertainty in population change, changes in renewal period, downsizing facility scale, and so on. In addition, perspectives for future facility maintenance were discussed in local areas with increasing waste treatment costs under population decline. As a result, it was revealed that periodical fundamental facility improvement contributes to reduce maintenance costs in mid and long term. Moreover, the study also revealed various enhancing strategies to reduce waste treatment costs, such as wide-area treatment by collaboration among local governments, increasing actual operation days than those in the operation plan, in addition to the periodical facility improvement, etc.

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  • Ganbold ENKHMUNKH, Eiji YAMASUE, Alessio MIATTO, Hiroki TANIKAWA
    2019 Volume 75 Issue 6 Pages II_285-II_290
    Published: 2019
    Released: March 16, 2020
    JOURNAL FREE ACCESS

     Mining, husbandry, and construction activities are consuming a large amount of natural resources. These processes have multiple impacts on the environment, including the excavation of large areas. This research focuses on gold mining in Mongolia, and aims (1) to identify the gold mining activities and allocated them on a map, and (2) to quantify the material flows related to gold mining. Statistical datasets, sourced by the Mineral Resources of Mongolia and the National Statistical Office of Mongolia, were used to account for domestic extraction. Two methods were used for mapping mining activities: firstly, the degraded areas were identified through a geographic information system (GIS) software; secondly, the domestic extraction of gold mining was estimated by the standardized method of material flow accounting. Results indicate the Mongolian gold mining activities exploited 9,812 ha of land across 18 different provinces. In addition, 745,300 m3 of soil was excavated to produce 132 tons of gold in 2007-2017. Particularly, during this period 100.8 tonnes of green gold was extracted which means the gold extraction that does not include any chemical process and just washing soil to obtain gold. "Green Gold" is recognized as less environmental impact by the European market.

     This study will be beneficial to the Mongolian government to better understand the environmental burden related to the gold mining activities in the country.

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