Greenhouse gas emissions from biogenic waste treatment: options and uncertainty

A simplified life cycle assessment was conducted to estimate greenhouse gas (GHG) emissions and energy production from each component of biogenic waste treated in an open dumping site, and by composting, anaerobic digestion, and incineration employed with additional options. The impact of uncertainties and sensitivities of the parameters in the treatment methods were investigated. We conducted a sensitivity analysis to identify the most sensitive parameters, and we discussed the relationship between uncertainty and sensitivity. Our results revealed that the moisture content of food waste and the biomass-derived carbon and methane concentration of the landfill gas of biogenic waste subjected to open dumping are the most sensitive parameters across all the treatment methods. The net GHG emissions from food waste treated in an open dumping site ranged over ten times (0.30 ? 3.67 Gg CO₂ eq/Gg). In addition, by employing additional options for the open dumping site, including soil cover, a landfill gas collection system, shifting to a semi-aerobic condition, and energy conservation by using a gas engine, we found that the net GHG emissions could be reduced by 10, 27.9, 37.4 %, and up to 56.7 %, respectively. Shifting to a semi-aerobic system is the most effective method for reducing GHG emissions, followed by landfill gas collection.     

Isolation and characterization of 3-nitrophenol-degrading bacteria associated with rhizosphere of Spirodela polyrrhiza

Introduction

The accelerated biodegradation of 3-nitrophenol (3-NP) in the rhizosphere of giant duckweed (Spirodela polyrrhiza) was investigated.

Materials and methods

Biodegradation of 3-nitrophenol in the rhizosphere of a floating aquatic plant, S. polyrrhiza, was investigated by using three river water samples supplemented with 10?mg?l^?1 of 3-NP. Isolation and enrichment culture of 3-NP-degrading bacteria were performed in basal salts medium containing 3-NP (50?mg?l^?1). The isolated strains were physiologically and phylogenetically characterized by using an API20NE kit and 16S rRNA gene sequencing.

Results and discussion

Accelerated removal of 3-NP (100%) was observed in river water samples with S. polyrrhiza compared with their removal in plant-free river water. Also, 3-NP persisted in an autoclaved solution with aseptic plants, suggesting that the accelerated 3-NP removal resulted largely from degradation by bacteria inhabiting the plant rather than from adsorption and uptake by the plant. We successfully isolated six and four strains of 3-NP-degrading bacteria from the roots of S. polyrrhiza and plant-free river water, respectively. Phylogenetic analysis based on 16S rRNA gene divided the 3-NP-degrading bacteria into two taxonomic groups: the genera Pseudomonas and Cupriavidus. The strains belonging to the genus Cupriavidus were only isolated from the roots of duckweed. All strains isolated from the roots utilized 3-NP (0.5?mM) as a sole carbon and energy source, indicating that they could have contributed to the accelerated degradation of 3-NP in the rhizosphere of S. polyrrhiza.

Conclusions

The rhizoremediation using S. polyrrhiza and its rhizosphere bacteria can be an effective strategy for cleaning up the 3-NP-contaminated surface waters.     

Mutagenicity of anaerobic fenitrothion metabolites after aerobic biodegradation

Previous studies have revealed that the mutagenicity of fenitrothion increases during anaerobic biodegradation, suggesting that this insecticide's mutagenicity could effectively increase after it pollutes anaerobic environments such as lake sediments. To investigate possible changes to the mutagenicity of fenitrothion under aerobic conditions after it had already been increased by anaerobic biodegradation, batch incubation cultures were maintained under aerobic conditions. The mutagenicity, which had increased during anaerobic biodegradation, decreased under aerobic conditions with aerobic or facultative bacteria, but did not disappear completely in 22 days. In contrast, it did not change under aerobic conditions without bacteria or under continued anaerobic conditions. These observations suggest that the mutagenicity of anaerobically metabolized fenitrothion would not necessarily decrease after it arrives in an aerobic environment: this would depend on the presence of suitable bacteria. Therefore, fenitrothion-derived mutagenic compounds may pollute the water environment, including our drinking water sources, after accidental pollution of aerobic waters. Although amino-fenitrothion generated during anaerobic biodegradation of fenitrothion was the principal mutagen, non-trivial contributions of other, unidentified metabolites to the mutagenicity were also observed.     

Features of fatal injuries in older cyclists in vehicle–bicycle accidents in Japan

Objective: The purpose of this study was to identify and better understand the features of fatal injuries in cyclists aged 75 years and over involved in collisions with either hood- or van-type vehicles.

Methods: This study investigated the fatal injuries of cyclists aged 75 years old and over by analyzing accident data. We focused on the body regions to which the fatal injury occurred using vehicle–bicycle accident data from the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. Using data from 2009 to 2013, we examined the frequency of fatally injured body region by gender, age, and actual vehicle travel speed. We investigated any significant differences in distributions of fatal injuries by body region for cyclists aged 75 years and over using chi-square tests to compare with cyclists in other age groups. We also investigated the cause of fatal head injuries, such as impact with a road surface or vehicle.

Results: The results indicated that head injuries were the most common cause of fatalities among the study group. At low vehicle travel speeds for both hood- and van-type vehicles, fatalities were most likely to be the result of head impacts against the road surface.

The percentage of fatalities following hip injuries was significantly higher for cyclists aged 75 years and over than for those aged 65–74 or 13–59 in impacts with hood-type vehicles. It was also higher for women than men in the over-75 age group in impacts with these vehicles.

Conclusions: For cyclists aged 75 years and over, wearing a helmet may be helpful to prevent head injuries in vehicle-to-cyclist accidents. It may also be helpful to introduce some safety measures to prevent hip injuries, given the higher level of fatalities following hip injury among all cyclists aged 75 and over, particularly women.     

Establishment of unit generation rates of building debris in Kathmandu Valley,Nepal, after the Gorkha earthquake

Journal of Material Cycles and Waste Management - Significant quantities of building waste were generated from collapsed residential and dilapidated buildings as a result of the disastrous Gorkha...     

Airborne hydrophilic microplastics in cloud water at high altitudes and their role in cloud formation

Microplastic pollution is occurring in most ecosystem, yet their presence in high altitude clouds and their influence on cloud formation and climate change are poorly known. Here we analyzed microplastics in cloud water sampled at the summits of Japan mountains at 1300–3776 m altitude by attenuated total reflection imaging and micro-Fourier transform infrared spectroscopy. We observed nine microplastics including polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyamide 6, polycarbonate, ethylene–propylene copolymer or polyethylene–polypropylene alloy, polyurethane, and epoxy resin. Microplastic were fragmented, with mean concentrations ranging from 6.7 to 13.9 pieces per liter, and with Feret diameters ranging from 7.1 to 94.6 μm. Microplastics bearing hydrophilic groups such as carbonyl and/or hydroxyl groups were abundant, suggesting that they might have acted as condensation nuclei of cloud ice and water. Overall, our finding suggest that high-altitude microplastics cloud influence cloud formation and, in turn, might modify the climate.

     

Growth inhibition and formation of morphologically abnormal cells of <Emphasis Type="Italic">Akashiwo sanguinea</Emphasis> (Hirasaka) G. Hansen et Moestrup by cell contact with <Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis> Margalef

We investigated the growth interaction between Cochlodinium polykrikoides and Akashiwo sanguinea using bi-algal cultures. When cultured together, morphologically abnormal cells of A. sanguinea appeared and the growth of A. sanguinea notably decreased. When C. polykrikoides and A. sanguinea were cultured separately in inner and outer wells separated by a membrane with a pore size of 3 μm, neither species showed suppressed growth and no morphologically abnormal cells of A. sanguinea were observed. Furthermore, filtrates from C. polykrikoides cultures did not affect the cell morphology or the growth of A. sanguinea. When the abnormal cells of A. sanguinea were transferred from bi-algal cultures into fresh medium and cultured as a mono-algal culture, cells recovered their normal morphology and multiplied. Therefore, the growth inhibition and formation of morphologically abnormal cells of A. sanguinea would be induced by constant cell contact with C. polykrikoides.     

Assessment of air pollution in Nagasaki City: determination of polycyclic aromatic hydrocarbons and their nitrated derivatives, and some metals

Air pollutants such as polycyclic aromatic hydrocarbons (PAHs), their nitrated derivatives (NPAHs), and some metals on airborne particles in Nagasaki city, Japan were determined over a period of 12 months by high-performance liquid chromatography with chemiluminescence, fluorescence and flameless atomic absorption spectrometry. The average concentrations (range) were 18.24 (4.07-41.54) ng/m3 for total PAHs, 0.91 (0.23-4.10) pg/m3 for NPAHs, 7.95 (1.71-16.31) ng/m3 for Pb, 11.56 (3.35-24.96) ng/m3 for Mn and 3.79 (0.97-14.71) ng/m3 for Ni (n = 136). The toxic equivalency factors adjusted concentration of total PAHs determined in Nagasaki city area was 2.33 ng/m3. Concentrations of total PAHs and NPAHs in winter were higher than those in summer. In a weekly variations study, total PAHs and NPAHs concentrations, as well as traffic volume showed a similar tendency with all values higher during weekdays and lower at the weekend. The correlation coefficients between total PAHs or NPAHs and traffic volume were 0.781 and 0.818, respectively. These results suggested that one of the main sources for NPAHs and PAHs in a city area might be motor vehicles.     

Multi-component behavior of fixed-bed adsorption of dioxins by activated carbon fiber

The multi-component behavior of fixed-bed adsorption of dioxins (DXNs) was examined through detailed analyses of the concentration profiles of isomers in fixed-bed activated carbon fiber (ACF). Regularities in both adsorption rates and strengths were clarified. (1) The rate of transfer in the adsorption of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCCDs/DFs) tends to increase with decreasing number of chlorine substituents. Axial dispersion also tends to increase with a decreasing number of chlorine substituents under our experimental conditions. (2) Homologues with the same number of chlorine substituents in PCDDs/DFs have similar adsorption strengths. The adsorption strength of PCDD/DF isomers is probably greater than that of co-planar polychlorinated biphenyls (co-PCB) isomers when the number of chlorine substituents is identical. (3) The adsorption strength of isomers depends on their molecular structure. In PCDDs/DFs the toxic isomers, all of which have vicinal chlorine substituents at the 2, 3, 7 and 8 positions, are relatively strong. It is clear, especially in TeCDDs, that isomers with vicinal chlorine substituents are stronger than isomers without. In co-PCBs, isomers without chlorine substituents at ortho positions are stronger than those with, and (4) A close analogy exists between the adsorption strength order for ACF and the elution order in gas chromatography (GC).     

Analysis of car-to-bicycle approach patterns for developing active safety devices

Objective: To reduce the severity of injuries and the number of cyclist deaths in traffic accidents, active safety devices providing cyclist detection are considered to be effective countermeasures. The features of car-to-bicycle collisions need to be known in detail to develop such safety devices.

Methods: The study investigated near-miss situations captured by drive recorders installed in passenger cars. Because similarities in the approach patterns between near-miss incidents and real-world fatal cyclist accidents in Japan were confirmed, we analyzed the 229 near-miss incident data via video capturing bicycles crossing the road in front of forward-moving cars. Using a video frame captured by a drive recorder, the time to collision (TTC) was calculated from the car's velocity and the distance between the car and bicycle at the moment when the bicycle initially appeared.

Results: The average TTC in the cases where bicycles emerged from behind obstructions was shorter than that in the cases where drivers had unobstructed views of the bicycles. In comparing the TTC of car-to-bicycle near-miss incidents to the previously obtained results of car-to-pedestrian near-miss incidents, it was determined that the average TTC in car-to-bicycle near-miss incidents was significantly longer than that in car-to-pedestrian near-miss incidents.

Conclusions: When considering the TTC in the test protocol of evaluation for safety performance of active safety devices, we propose individual TTCs for evaluation of cyclist and pedestrian detections, respectively. In the test protocols, the following 2 scenarios should be employed: bicycle emerging from behind an unobstructed view and bicycle emerging from behind obstructions.