Journal of Material Cycles and Waste Management

Remanufacturing retired auto parts with high added value can save various resources and provide good environmental benefits. This paper uses GREET2021 software to analyze and calculate the energy consumption of the life cycle, the primary energy consumption in each stage, quantify the emission of greenhouse gas and standard pollutants of a small internal combustion engine (ICE) passenger car with remanufacturing starter, and conducts a comparison study with a small ICE passenger car equipped with a new starter based on life cycle assessment. Results show that a small ICE passenger car with a remanufacturing starter consumes 40 kJ less energy per 100 km, emits 0.2 g less CO2, and emits 0.005 g less PM2.5 and PM10 than a small ICE passenger car with a new starter. The uncertainty analysis shows the fuel production phase has the highest uncertainty of 67.6% for CO2 emissions over the life cycle of passenger cars. The sensitivity analysis shows that a small ICE passenger car with remanufacturing starter is less sensitive in terms of life cycle energy consumption, primary energy consumption, and major pollutant emissions.

The present study conducted lead sorption experiments using wood ash to elucidate its capacity and mechanisms of lead removal, to evaluate the recovery of lead removed by wood ash and the reuse of wood ash residue left after lead recovery. The maximum lead removal capacity of wood ash was 3.08 mmol g−1, which was higher than previously reported values. An X-ray diffraction analysis showed that the lead phase removed by wood ash was mainly hydrocerussite probably resulting from the sequential reactions of wood ash with lead ions, dissolution of carbonate ions from wood ash, precipitation of cerussite reacting with lead ions and then alteration to hydrocerussite from cerussite. In addition to the precipitation of hydrocerussite, lead sorption by the acid-insoluble matter in wood ash was also evident. The percentage of lead removed by wood ash in pH 2 solution was very low at 17 %, whereas that at pH 6 was 99 %. Almost all lead removed by wood ash was easily recovered using 0.1 M HNO3, and the residue remaining after lead recovery was able to remove lead repeatedly at rates of 13–22 mg g−1.

The sludge from a steel processing unit bearing zinc, lead, iron, and manganese was solidified with ordinary Portland cement. The waste was stabilized in the specimens with a waste/binder ratio range of 0.16–4.0. On the basis of the available leaching and unconfined compressive strength, the performance of the solidified/stabilized waste was compared for different numbers of curing days. It was found that curing up to 28 days resulted in a performance improvement, as shown by less leaching of heavy metals and the increased unconfined compressive strength of the specimen. The treatment effectiveness of the solidification/stabilization process was assessed for the metals Pb, Zn, Fe, and Mn, and was found to be 89%, 95%, 74%, and 90%, respectively, for an optimum ratio of 4.0 after 28 days of curing.

The potential of replacing fruit and vegetable wastes (FVW) as remarkable sources of environmentally offensive biomass in metropolises with organic fraction of municipal solid waste (OFMSW) on biogas production was investigated. Components of OFMSW as a source separated MSW were prepared in 5 categories of fat and protein, starch, cellulose, fruit, and vegetable waste. Experiments were carried out in four FVW/OFMSW replacement ratios (wet basis) of 0, 15, 30 and 45% at two total solid (TS) concentrations of 8% and 15% at 37 °C. Main results indicated that co-digestion is favorable at lower TS content (8% TS) and higher FVW/OFMSW ratios up to 30%. Although methane yield did not improve significantly for these substitution ratios, the concentration of methane in the biogas enhanced up to 68% and about 92% of volatile solids’ removal achieved. Kinetics study, based on lag phase of Gompetz model, indicated process rapidity increased proportionally to the FVW replacement ratios. Dedication up to 30% of feedstock capacity of ongoing OFMSW biogas plants in metropolises with FVW can suggest more revenue for plants through lowering HRT, increasing biodegradability of substrate, removing undesirable gas and supplying water needed for anaerobic digestion.

Việc chuyển hóa đồng thời các nguyên liệu kết hợp trong môi trường yếm khí cải thiện sản lượng biogas nhờ vào sự cân bằng tốt hơn của các chất dinh dưỡng trong môi trường tiêu hóa. Một lựa chọn phù hợp để nâng cao sản lượng biogas từ quá trình tiêu hóa yếm khí chất thải rắn đô thị là việc chuyển hóa đồng cùng với các vật liệu lignocellulosic. Sự khai thác ngày càng tăng của cây sậy khổng lồ trong một số lĩnh vực công nghiệp đã thúc đẩy một cuộc khảo sát sơ bộ về việc chuyển hóa đồng thời của sậy khổng lồ bị phát nổ hơi nước và phần hữu cơ của chất thải rắn đô thị (OFMSW). Quá trình tiêu hóa yếm khí được thực hiện ở 37 °C, trong chế độ hoạt động theo mẻ. Khối lượng biogas được sản xuất và các biểu đồ nồng độ - thời gian của axit béo bay hơi đã được phân tích cho các tỷ lệ ban đầu khác nhau của nguyên liệu kết hợp. Tất cả các hỗn hợp đều hoạt động tốt hơn so với nguyên liệu đơn lẻ. Sản lượng biogas tối ưu đạt được với việc chuyển hóa đồng của một hỗn hợp chứa 75% OFMSW và 25% cây sậy khổng lồ, sản xuất ra 236 mL CH4/g VS với mức tăng 1.5 lần so với quá trình tiêu hóa OFMSW đơn lẻ.

Shortly after the March 11th earthquake and tsunami in eastern Japan, a Task Team for Disaster Waste Management and Reconstruction was established within the Japan Society of Material Cycles and Waste Management (JSMCWM). One of the major tasks undertaken by the team was to create a manual entitled, Strategies for Separation and Treatment of Disaster Waste. In this paper, this JSMCWM manual is introduced, followed by a review of existing guidelines for disaster waste management in various countries. We identify useful guidelines created by international agencies, national and local governments. The JSMCWM manual adds our new experiences, especially characterized by a huge scale of disaster and tsunami information, to the existing knowledge with an emphasis on separation and subsequent treatment options. It should be desirable to share our knowledge and experiences, not only domestically but also with other countries in the world, especially regions that could be affected by large earthquake and tsunami events.

Although fly ash, as used for supplementary cementitious material in Portland cement concrete, can reduce the heat of hydration and suppress the expansion caused by alkali-silica reaction (ASR), the early strength development of the concrete tends to be lower. On the other hand, it is known that the strength development can be improved using cement clinker as the aggregate for concrete (CL). However, there is a risk of ASR in using CL due to the alkali leaching from the CL. Therefore, the combined use of fly ash and CL may have a synergistic effect. Based on these considerations, we examined the effect of using fly ash and CL in combination on the internal temperature of mortar, strength development, and ASR. We demonstrate that the combined use of CL and fly ash results in good strength development as well as suppressing the internal temperature. In addition, when the binder was only ordinary Portland cement (OPC), the combination of CL and ASR reactive aggregate enabled reducing the expansion caused by ASR compared to the combination of limestone aggregate (LS) and ASR reactive aggregate. However, the higher the replacement ratio of fly ash for OPC, the lower its ASR suppression effect.

The paper presents the results on the analysis of non-hazardous waste generation characteristics and recycling practices in Saskatchewan (SK) and Manitoba (MB) using the biennial waste reports published by Statistic Canada. The objectives are to examine the waste generation rates from both residential and non-residential sources from 1998 to 2010, and to evaluate the effectiveness of their recycling programs and regulations. In spite of the many similarities between the provinces, MB on average generated 17.5 % more residential waste than SK, and about 15 % less non-residential waste than SK during the study period. It appears that MB waste generation characteristics were very different from SK and the rest of Canada. The amount of MSW generation in MB was, to a certain degree, independent from the economic factors. Assuming status quos conditions, the linear models predicted that the per capita MSW generations in MB would be about 33 % lower than SK in 2020. Data from this study suggest that (1) curbside recycling programs and (2) pay-as-you-throw collection systems may be important factors for increasing diversion rate in SK. It is also found that the non-residential waste generation in Canada was substantially larger than the residential waste generation during the 13-year period.

Anaerobic digestion is known to eliminate many kinds of microorganisms in livestock wastes. In this study, the quantitative changes of Pseudomonas species during mesophilic and thermophilic anaerobic digestions were investigated with focus on P. aeruginosa and P. fluorescens, which are known as a pathogen and a plant growth-promoting rhizobacterium, respectively. Furthermore, quantitative changes in antimicrobial-resistant Pseudomonas species against cefazolin were also investigated as a representative of antimicrobial resistance in dairy farms. The quantitative measurement of Pseudomonas species was performed by a plating method with modified Pseudomonas-selective agar medium. The colonies on the agar plates were classified into three groups by their colour development and constitutional fluorescence, and the group to which P. aeruginosa and P. fluorescens belong was confirmed by colony PCR using species-specific primers. The results revealed that while the number of total Pseudomonas decreased, the number of fluorescent Pseudomonas including P. fluorescens increased after anaerobic digestion. The abundance of cefazolin-resistant Pseudomonas also decreased, and no P. aeruginosa could be detected in any samples. These results suggested that the digestate has benefits such as the absence of pathogenic risks led by the Pseudomonas species and is expected to have a plant growth-promoting effect facilitated by fluorescent Pseudomonas.