The aim of this study is to show prospects for the practice of and research related to estimating the amount of disaster waste. The paper looks at these issues from the viewpoint of disaster response and management. Our hope is that this can contribute to both preparedness and response for future disaster waste scenarios. A total of 23 different estimation methods were identified from our literature survey covering two academic journal databases (JDreamⅢ, CiNii). These were then categorized and analyzed for their potential role in different disaster management phases. Results reveal that the estimation methods which are currently in use or being developed have different characteristics in terms of scope, universality, and information needed for estimation. Such implications indicate a need to clearly acknowledge the applicability in these different situations. We finally propose strategies for estimating the amount of disaster waste according to the types of disasters and the phases of the disaster, keeping in mind the differences in access to information. We introduce research issues where priority must be given in order to fully realize these strategies.
Wool textile waste is composed mainly of protein that can be hydrolyzed to generate amino acids. For the purpose of recycling, wool waste is subjected to pressurized hot water treatment to convert the protein to water-soluble protein, followed by hydrolysis of the water-soluble protein using cation exchange resins as catalysts. However, the wool proteins often undergo excessive decomposition during the pressurized hot water treatment. The present study examined methods for suppressing the excessive decomposition and optimizing conditions for hydrolysis of the water-soluble proteins. The results indicate that the excessive decomposition can be suppressed by shortening the retention time using a semi-flow reactor. In addition, a high ion-exchange capacity and an increase in the resin density in the reaction vessel effectively promoted hydrolysis.
Using a laser exhaust gas analyzer installed at an incinerator outlet, the authors measured O2, H2O, and CO2 concentrations in exhaust gases. The amounts of oxidation reactions of C and H in the waste and the H2O evaporation amount were calculated from the measurement results. The amount of heat generated by the waste combustion was calculated. Furthermore, the heating value of the waste was calculated. The generated calorific value showed good agreement with the estimate based on the heat balance around the incinerator, indicating high estimation accuracy. Moreover, comparison with the analysis result showing a lower measured heating value of waste, revealing large error in conventional heating value estimation. Furthermore, because the measured heat generated by exhaust gas components can be predicted in advance of the boiler evaporation amount, combustion can be stabilized when applied to combustion control. Benefits such as increased electrical generation were confirmed from reduced fluctuation of boiler evaporation.
This paper estimates the effects of unit-based pricing on municipal solid waste in Japan from data generated by a municipal-level panel created to examine the municipal mergers known as “the big merger of Heisei.” Previous studies had used data from a pre-merger panel due to the fact that data regarding the merged municipalities had been lost following the finalization of the mergers. In order to observe the current effects of unit-based pricing on municipal solid waste after the period of the mergers, this study has created panel data using hypothetical data from merged municipalities. It was created in order to incorporate certain data that was generated before the mergers took place. Considering the effects of municipal mergers, empirical results from the created panel data show that both simple unit-pricing and two-tiered pricing programs decreased the amount of municipal solid waste after being introduced. Moreover, the restraining effects continued over a long period of time. The restraining effects are being underestimated because the effects of these municipal mergers are not being fully taken into consideration. Results also show the mergers that were a part of ‘the big merger of Heisei’ have increased the amount of municipal solid waste.
The prevention of damage to super-heater tubes due to high-temperature corrosion caused by various components in MSW is a key to the wider dissemination of waste power generation. To suppress corrosion by using additives is one type of effective method. In these methods, however, it is important to minimize the amounts of additives used, because of increasing additive costs and ash treatment amounts. In this study, for the purpose of selecting additives with high capabilities, several additives were compared and evaluated using laboratory tests that simulated the environment of an actual stoker-type waste incinerator boiler. As a result, the suppression effect of natural zeolite was found to be the highest among the tested samples. Natural zeolite was mixed in deposit ash collected from an actual plant and tested, and the suppression effect was observed to be between 5 and 25 mass-%. It was also found that zeolite captures gaseous corrosive components and acid gases. The former suggests the possibility of an even greater suppression effect when used in actual plants. The latter shows the possibility of being applicable as an acid gas treatment agent.
Reverse logistics (RL) is an important component of both corporate strategies and social systems. Corporations are expected to get more deeply involved in RL as their environmental responsibilities increase. In this paper, we review previous studies from Japan and other countries to uncover the fact that research on Japanese reverse logistics (JRL) has been inadequate, quantitatively and qualitatively, when compared with RL studies around the world. Through our study, we also found out some of the reasons behind this deficiency in accumulatedresearch : a practical need appears to be lacking, which stems from Japan′s institutional historical perspectives, the difficulties in conducting seeds study due to its unique legalities related to waste and recycling among other issues. Moreover, we generated suggestions for developing the Japanese RL (JRL) system and related research fields. One such example is to embrace the management concept to the same extent as RL systems in other countries have, as a means of expanding its scope and establishing an international RL system based on Japanese geographical characteristics. We also extracted core publications to be followed in order to build up more efficient RL research that will require the application of social network analysis in Japan for the future.
This study focuses on the location decisions of private disposal sites for industrial waste. Using a unique dataset of industrial waste disposal sites from 1977 to 2012 in Japan and an econometric approach, we investigate trends in site selection for private industrial waste disposal locations. We also investigate the characteristics of communities that tend to locate disposal sites. Our results show that the number of disposal sites being constructed decreased after the Japanese waste disposal law revision was implemented in 1997 and 1998. In addition, we found that the introduction of an industrial waste tax and trade restrictions on industrial waste shipments tend to decrease the number construction of sites for industrial disposal.
Generally, bio-wastes have high moisture. However, they have high caloric values if they are dried. Composting is one of the traditional recycling methods for them. It uses aerobic biological reactions. The high temperature that results from self-heat generation and the aeration for oxygen supply make the product dryer than the original. This phenomenon shows that effective drying can be achieved if this process is controlled well. However, it is not easy to find optimum operational conditions, because this process is very complicated with many environmental and operational factors. In this research, a simulation program that describes this process was developed. By comparing simulated results with the results of drying experiments, the validity of the simulation program is discussed.
A numerical simulation including a municipal solid waste (MSW) combustion model and an NOX prediction model with a detailed chemical kinetics mechanism for a stoker-type MSW incinerator was developed. In this model, the waste bed layer on stoker grates was expressed as groups of waste particles using the Euler-Lagrange approach. In order to reduce the computational load, the NOX concentration was calculated using a decoupled detailed chemical (DDC) model. The model was validated by comparison with a combustion test in a small-scale incinerator. The calculation results could express the distribution of temperature, the flow pattern in the incinerator and the CO concentration at the outlet. In order to conduct NOX prediction, at least 8 species should be selected as pollutant species in the DDC model. Furthermore, accounting for 13 pollutant species gave better accuracy. These results showed the usefulness of the model.
The aim of this study is to graspthe actual redundant capacity of waste treatment plants as a means of evaluating possible disaster prevention countermeasures. Results of the study reflect the potential for waste treatment plants to serve as regional disaster response facilities. We first investigated the damage ratio for incineration plants and bulk waste treatment facilities in Japan based on combining the vector data of plant locations and information from seismic damage distributions using GIS; of main concern was the case of the great earthquakes that occurred in the Nankai trough. In the next step, we conducted a questionnaire-survey of 1,361 municipalities throughout Japan. The redundant capacity of waste incineration plants was calculated using the maximum working hours derived from this survey. Finally, we conducted a case study to evaluate the redundant capacity of incineration plants operated by municipalities after the presumed great earthquake along the Nankai trough that struck.
The feasibility of the anaerobic co-digestion of cow manure (CM) and energy crops (EC) was investigated in both batch and continuous experiments. A positive synergistic effect (about 8 %) for methane yield was observed by co-digesting CM and EC in batch experiments. Completely-mixed reactors for mono-digestion of CM and co-digestion of CM and EC (either dent corn or rice straw) were semi-continuously operated at a constant influent VS level of 10 %. The VS mixing ratio was set at 1 : 0.5 (EC/CM) in co-digestion. Stable and efficient co-digestion at hydraulic retention times (HRTs) of 30 days (mono-digestion basis) were obtained. Methane production increased by 61 % and 45 % in the dent corn co-digestion and the rice straw co-digestion, respectively, compared with the mono-digestion. At HRTs of 22.5 days (mono-digestion basis), the performance of co-digestion was also stable. Methane production increased by 57-72 % in the co-digestion reactors compared with mono-digestion. The results suggested that EC can be used as a co-substrate of CM anaerobic digestion for a significant methane production increase.
After low-level liquid radioactive wastes generated from nuclear power stations are asphalt-solidified and emplaced in drums, they are entombed in burial disposal facilities. Those radioactive wastes contain chemicals such as boron, which can cause environmental impacts aside from those of radionuclides. The leaching characteristics of radionuclides from asphalt solidified waste have been discussed in many reports. However, no study case for boron has been reported. For this study, leaching tests of 1000 days were conducted to comply with the IAEA (International Atomic Energy Agency) test method used for simulated asphalt solidified wastes. Results confirmed the leaching characteristics of chemical substances such as boron and radionuclides. Furthermore, surface and cross-sectional surface observations were conducted over time using SEM (Scanning Electron Microscope) and other analytical modes. Results revealed leaching characteristics and cross-sectional surface observations for leaching of substances from inside of the solidified waste through a rate-limiting process by which immersion water penetrates into the solidified waste by diffusion. Presumably, the leaching can be evaluated using a diffusion model. Its diffusion coefficient can be evaluated as approximately 1 × 10－15m2/s, irrespective of the species of immersion water and chemical elements (except for low solubility substances).
Waste layers that include plastics and similar wastes generally have extremely high rainwater permeability because they contain large voids. However, as a result of test pitting at an inert waste landfill and large column tests using specimens from landfills, it was found that some rainwater was retained on the surface of plastics for a long time and that the water seeped down very slowly. In addition, it was inferred that rainwater contributes to the settlement of waste layers that include plastics. The water retained on the surface of plastics might contribute to settlement. In addition, it can be seen that water seeping down slowly from the surface of the plastics causes the total organic carbon concentration in the water to rise in large column tests. For the large column tests and the inert waste landfill that includes plastics in the Chubu district, seepage calculations were performed with retention function equations. The amounts of water seepage could be calculated with the retention function equations.
Household food waste has become a major problem that can only be overcome through certain concrete changes in consumer behaviors. In order to significantly reduce food waste at the domestic level, food behaviors that need to be changed must first be systematically identified. In an attempt to come up with solutions for this issue, I have thoroughly examined the results and research methodologies of previous studies and in this paper I discuss the types of behaviors that result in the generation of large amounts of food waste. Many studies on food waste have been published recently, with some of the authors demonstrating that particular behaviors, such as removing edible parts during food preparation and not actively using ingredients stored in refrigerators and cupboards, inevitably produce a huge quantity of food waste. Authors also point out how consumers often decide to throw away food because of the labeled expiry dates. Finally, I recommends that it is important to fully examine what measures could be taken to change these behaviors and reduce overall food waste.
Amounts of gas, composition, thermodynamic properties, etc. of combustion gases formed from combustible MSW incineration processes are prerequisite information for system analysis to raise standards for the design, operation, and maintenance of MSW incinerators. However, it has been regarded as difficult to evaluate the representative values precisely for these quantities because of the heterogeneity of waste and corresponding fluctuations of measurements. In this study, data collected from fed-waste surveys and operational records of MSW incinerators in a Tokyo special ward district in FY2016 have been reorganized in terms of the heat balance consistency of the incineration systems. Basic parameters of the standardized combustion gas model have been established by calculating the amount of combustion gas per unit mass of waste, mean constant-pressure specific heat, specific heat content of combustion gas, composition functions, etc. Results from this study provide in-depth knowledge about actual combustion gases in addition to frameworks for further analytical modeling.
Radioactive cesium concentrations in flue gas are measured using the official analytical method stipulated by the Ministry of the Environment. Using this method, radioactive cesium is analyzed for dust collected by filters and fluids collected in impingers. Although filters are known to collect sufficient radioactive cesium in flue gas, no detailed data are available for their ability to collect ultrafine particulate matter. Therefore, this study was conducted to evaluate the official analytical method by measuring the number concentration of particles in the actual incinerator flue gas. Results demonstrate that the number concentration of ultrafine particles (particles with < 0.3 μm diameter) at the bag filter inlet is 106cm−3N, although it is 102cm−3N at the outlet of the impinger. This finding demonstrates that approximately 99.99 % of the ultrafine particles can be captured using the official analytical method. Furthermore, when the radioactive cesium in the collected particles at the outlet of the impinger was analyzed, its concentration was found to be below the limits of detection. This finding confirms that the official analytical method is appropriate for taking samples of radioactive cesium in flue gas.
To clarify the inhibition effect of swine manure compost-based char on the biological treatment of swine wastewater with NH4-N removed (NRSWW), NH4-N removal experiments and batch biological treatment experiments were performed. NH4-N removal and C/N ratios in NRSWW increased with the char addition ratio, reaching 40 % and 1.5 at a char addition ratio of 20 %, respectively. The increase in a C/N ratio was affected by TOC dissolution from the char in addition to NH4-N removal by the char. NH4-N removal by the char exhibited no inhibition of TOC removal. Biological nitrification was inhibited by NH4-N removal by the char when the char addition ratio was over 10 %. Chloride ions might be considered an inhibitor of nitrification. No accumulation of nitrate and nitrite appeared, so denitrification occurred sufficiently.
In addition to base metals such as copper and lead, precious metals such as gold and silver are contained in the molten metals of incineration residue. Based on this fact, technologies exist to concentrate and melt incineration residues to recover resources at nonferrous refining facilities. This study specifically examined this centralized reductive melting and compared resource substitution and LCCO2 with conventional uses of alternative raw materials in the cement industry and for the use of roadbed materials by aging. First, material flow analysis was conducted based on the existing literature and process data from actual operation facilities. Next, setting the base scenario as landfill disposal, we evaluated the degree to which recovered metals can be substituted for natural ore. Results show that approximately 1ton of incineration residues can provide several kilograms to several tens kilograms of copper, lead, and zinc concentrates, and approximately 1ton of gold and silver ore, using reductive melting. The LCCO2 analysis results demonstrated that greenhouse gas (GHG) emissions will be increased, but future changes in power composition and site location optimization offer the possibility of producing less GHG emissions than landfill disposal.
We conducted geotechnical surveys and evaluations for the adjustment of final disposal site problems that have been identified from the perspective of safety, including risk management. There have been several landslides around this final disposal site. At this final disposal site, we carried out surveys of groundwater level, ground displacement and geophysical prospecting from the point of view of mechanical stability. As a result, we showed that we can properly grasp the size and situation of landfilled waste with geological engineering methods. Moreover, landslides around this final disposal site are stabilized, but, if old waste from the Showa period (1975-1989) were cut out, destabilization could cause landslides. Further, the possibility exists that waste layers could also be destabilized when large earthquakes occur because there are many waste layers with high moisture content in this site. Thus, it is necessary to leave the old waste, which forms holding embankments and to drain internal water from this site.
Oil-water separation of cutting drainage using a spiral cross flow with ceramic filter was conducted. Hollow ceramic filter (1.2μm and 2.5μm openings) with a spiral rod was used as a separation membrane. In the separation experiment, water separation from real cutting drainage, which contained water, mineral oil, detergent and cutting dust, was conducted, and the effect of separation conditions, including emulsion rate, filter opening, and emulsion type, on the separation rate and separation ratio was evaluated. As results, the spiral cross flow using a ceramic filter had the capability to separate water from cutting drainage, and the oil ratio in the separated water was less than 1% regardless of the separation conditions and emulsion types. The separation ratio over the treatment time remained constant at a high value regardless of the separation time. As FT-IR analysis of the filtrate, mineral oil components and water in the cutting drainage were completely separated by the ceramic filter. Water soluble components, such as fatty acid, on the other hand, could not be separated by the ceramic filter.
In Japan, most combustible wastes are incinerated. Due to the need to reduce fossil fuel consumption used for incineration and the necessity to utilize kitchen waste as biomass, there is a growing demand for technology to separate kitchen waste from combustible waste and to utilize it as an energy source. In this research, a Mechanical-Biological Treatment (MBT) system, which is a technology combining mechanical sorting and methane fermentation, was developed and sorting and fermentation tests were conducted using municipal waste. The results showed that it is possible to separate kitchen waste as fermentable material from combustible waste with high accuracy by means of shredding and screening, and that 150Nm3 of biogas per ton of fermentable material can be stably produced by mesophilic methane fermentation of the recovered fermentable material. In addition, the lower calorific value of combustible material after separating kitchen waste improved by 1.7times compared to before separation, indicating that this is effective as a high-efficiency incineration and fuelization technology.
From the viewpoint of waste reduction and effective utilization of resources, collection and recycling of papermaking raw materials from used paper products is of utmost importance. For various reasons, however, pulp that is extracted from disposable diapers is almost never recycled. In response to this, we have been working to develop a technology that collects safe, fine pulp from used disposable diapers for adults. The system sterilizes and disinfects using an ozone treatment process. In our research, a flow scheme consisting of residual protein analysis, element analysis, analysis of residual organic chemical substances and analysis of chlorine compounds has been constructed in order to evaluate the safety in the chemical aspect of pulp obtained by recycling used disposable diapers. The flow scheme has been applied to recycled pulp from diapers actually obtained through ozone treatment and we are now able to confirm that this recycled, ozone-treated pulp conforms to public standards for hygienic raw materials.
In order to clarify the effect of wastewater recovered from swine production on the simultaneous recovery of ammonia, phosphate and potassium, a recovery experiment was carried out using six kinds of primary treatment water obtained from three hog farms in September and November. The compositions of the recovered materials were also investigated. The remaining concentrations of nitrogen, phosphate, potassium and magnesium could be predicted by previously reported methods. The prediction accuracy ranged from half to double the observed concentrations. Under conditions where the observed remaining concentrations of phosphorus were less than 16 mg/L, nitrogen recovery was over 96 %, but the maximum potassium recovery was 67 %. Net phosphorus recovery was over 40 % indicating that more could be recovered more than required to meet wastewater standards. The average nitrogen, phosphate, potassium and magnesium contents in the recovered materials were 19, 19, 3.4 % and 1.4 %, respectively. For these components, more than 80 % of the content was citric acid-soluble. MgNH4PO4・H2O was identified in recovered materials, but others were not. The phosphorus contained in recovered materials was 39 % as MAP, 6 % as MPP and 55 % as other compounds.