Environmental and Energy Assessment of Biomass Residues to Biochar as Fuel: A Brief Review with Recommendations for Future Bioenergy Systems

This study explores the environmental and energy benefits of biomass residues, including crop residues and agricultural waste, for the production of renewable energy in the form of biochar as fuel, in order to offer recommendations for policy makers, by reviewing information regarding the key environmental issues associated with the implementation of the systems. The highest environmental benefits for biochar-to-fuel systems were most observed in reduction of global warming potentials (i.e., carbon abatement), particularly for those integrated with combined heat and power technology, or for those incorporating electricity offsets from biochar combustion and co-firing. But all of these practices come at the cost of hidden environmental burdens, such as elevations in eutrophication, acidification, carcinogens and ecotoxicity impacts, as a consequence from land use change, additional infrastructure requirement or additional fertilizer application connected to biochar production or post-treatment. Other notable challenges, including regional availability of biomass residues, improper management of the residues, limited economic incentives, low energy efficiency and synergies, as well as mistreating adverse impacts from indirect land use change, were discussed. This suggests the flexibility to adjust the biomass-biochar ratio to optimize desired energy yields, carbon abatement and environmental beneficial objectives. Comprehensive analysis of the trade-offs between energy yields, carbon abatement and other associated environmental impacts is therefore recommended for future studies. Future studies in this field are also advised to explore the solution and to develop methodologies capable of quantifying the impacts and other equally relevant trade-offs, to better reflect the changes in real-world trends for decision making

Spatiotemporal impact of COVID-19 on Taiwan air quality in the absence of a lockdown: Influence of urban public transportation use and meteorological conditions

The unprecedented outbreak of COVID-19 significantly improved the atmospheric environment for lockdown-imposed regions; however, scant evidence exists on its impacts on regions without lockdown. A novel research framework is proposed to evaluate the long-term monthly spatiotemporal impact of COVID-19 on Taiwan air quality through different statistical analyses, including geostatistical analysis, change detection analysis and identification of nonattainment pollutant occurrence between the average mean air pollutant concentrations from 2018–2019 and 2020, considering both meteorological and public transportation impacts. Contrary to lockdown-imposed regions, insignificant or worsened air quality conditions were observed at the beginning of COVID-19, but a delayed improvement occurred after April in Taiwan. The annual mean concentrations of PM10, PM2.5, SO2, NO2, CO and O3 in 2020 were reduced by 24%, 18%, 15%, 9.6%, 7.4% and 1.3%, respectively (relative to 2018–2019), and the overall occurrence frequency of nonattainment air pollutants declined by over 30%. Backward stepwise regression models for each air pollutant were successfully constructed utilizing 12 meteorological parameters (R2 > 0.8 except for SO2) to simulate the meteorological normalized business-as-usual concentration. The hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) model simulated the fate of air pollutants (e.g., local emissions or transboundary pollution) for anomalous months. The changes in different public transportation usage volumes (e.g., roadway, railway, air, and waterway) moderately reduced air pollution, particularly CO and NO2. Reduced public transportation use had a more significant impact than meteorology on air quality improvement in Taiwan, highlighting the importance of proper public transportation management for air pollution control and paving a new path for sustainable air quality management even in the absence of a lockdown

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Reconstructing nutrient criteria for source water areas using reference conditions

Nutrient concentrations are of concern in most watershed areas that serve as source water for public drinking water due to the high cost of nutrient removal treatment. Yet all nutrients criteria for source watersheds in Taiwan are identical for quality standards and the specific conditions of each source watershed were not considered. Nutrient RCs estimated by statistical methods and land disturbance modeling were applied to the Tamsui River in Taiwan. The results were then used to evaluate the nutrient status of Taipei Water Source Domain, which is located near the upstream portion of Tamsui River. The estimated RCs of NH3-N, TP, and Total N were 0.03–0.04, 0.019 to 0.036, and 1.22–1.50 mg L−1, respectively. Comparing with current criteria of NH3-N (0.1 mg L−1), the estimated reference conditions are lower and the criteria could be stricter to maintain sufficient water quality. However, the reference condition of TP estimated by the disturbance modeling (0.03 mg L−1) is higher than current criteria (0.02 mg L−1), leading to a possible loosening adjustment

A review on microwave pyrolysis of lignocellulosic biomass

AbstractThis article briefly reviews the technique of lignocellulosic biomass pyrolysis by using microwave heating. Lignocellulosic biomass, such as crops, wood, agricultural and forestry residues, is a major biomass resource and has been recognized as a sustainable feedstock for the production of bioenergy and green materials. Microwave heating can be better than conventional heating because of various advantages. Hot spots, which form under microwave irradiation, would have significant influence on the yield and characteristics of microwave processing products. The solid products of microwave pyrolysis at proper microwave power levels can have high heating values and specific surface areas with higher gas and solid yields but lower liquid yield than conventional pyrolysis. By using microwave pyrolysis, almost half of lignocellulosic biomass can be converted into gas product, which is mainly composed of H2, CH4, CO, and CO2, with more bioenergy because of its high H2 and CO yields. The addition of proper catalysts provides substantial influence on the product selectivity of microwave pyrolysis. The gas and liquid yields as well as the heating performance of microwave pyrolysis can be dramatically promoted by adding catalysts. The activation energy and pre-exponential factor of microwave pyrolysis are much lower than those of conventional pyrolysis, revealing that the reaction kinetics for the two methods could be different. According to various advantages, microwave pyrolysis of lignocellulosic biomass can be a promising bioenergy technique