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Macroalgae can be grown in industrial waste water to sequester metals and the resulting biomass used for biotechnological applications. We have previously cultivated the freshwater macroalga Oedogonium at a coal-fired power station to treat a metal-contaminated effluent from that facility. We then produced biochar from this biomass and determined the suitability of both the biomass and the biochar for soil amelioration. The dried biomass of Oedogonium cultivated in the waste water contained several elements for which there are terrestrial biosolids criteria (As, Cd, Cr, Cu, Pb, Ni, Se and Zn) and leached significant amounts of these elements into solution. Here, we demonstrate that these biomass leachates impair the germination and growth of radishes as a model crop. However, the biochar produced from this same biomass leaches negligible amounts of metal into solution and the leachates support high germination and growth of radishes. Biochar produced at 750 °C leaches the least metal and has the highest recalcitrant C content. When this biochar is added to a low-quality soil it improves the retention of nutrients (N, P, Ca, Mg, K and Mo) from fertilizer in the soil and the growth of radishes by 35-40%. Radishes grown in the soils amended with the biochar have equal or lower metal contents than radishes grown in soil without biochar, but much higher concentrations of essential trace elements (Mo) and macro nutrients (P, K, Ca and Mg). The cultivation of macroalgae is an effective waste water bioremediation technology that also produces biomass that can be used as a feedstock for conversion to biochar for soil amelioration.

Direct mineral carbonation (MC) is used to mitigate carbon dioxide (CO2) emissions. This method has the great advantages of reducing the amount of industrial residues and creating valuable materials by incorporating CO2. Waste gypsum, industrial waste including flue gas desulfurization (FGD) gypsum (25.27–53.40 wt% of CaO), and phosphogypsum (30.50–39.06 wt% of CaO) can be used for direct MC (conversion rate up to 96%). Mineral carbonation converts waste gypsum into calcium carbonate (CaCO3), which can be recycled during desulfurization. Furthermore, ammonium sulfate ((NH4)2SO4), which is used as a fertilizer, can be prepared as a by-product when the carbonation reaction is performed using ammonia (NH3) as a base. In this study, recent progress in the carbonation kinetics and preparation of CaCO3 using FGD gypsum and phosphogypsum with NH3 was investigated. Temperature, CO2 partial pressure, CO2 flow rate, and NH3 concentration were reviewed as factors affecting carbonation kinetics and efficiency. The factors influencing the polymorphs of the prepared CaCO3 were also reviewed and summarized. A state-of-the-art bench-scale plant study was also proposed. In addition, economic feasibility was investigated based on a bench-scale study to analyze the future applicability of this technology.

Biogas is one of the most attractive renewable resources due to its ability to convert waste into energy. Biogas is produced during an anaerobic digestion process from different organic waste resources with a combination of mainly CH4 (~50 mol/mol), CO2 (~15 mol/mol), and some trace gasses. The percentage of these trace gases is related to operating conditions and feedstocks. Due to the impurities of the trace gases, raw biogas has to be cleaned before use for many applications. Therefore, the cleaning, upgrading, and utilization of biogas has become an important topic that has been widely studied in recent years. In this review, raw biogas components are investigated in relation to feedstock resources. Then, using recent developments, it describes the cleaning methods that have been used to eliminate unwanted components in biogas. Additionally, the upgrading processes are systematically reviewed according to their technology, recovery range, and state of the art methods in this area, regarding obtaining biomethane from biogas. Furthermore, these upgrading methods have been comprehensively reviewed and compared with each other in terms of electricity consumption and methane losses. This comparison revealed that amine scrubbing is one the most promising methods in terms of methane losses and the energy demand of the system. In the section on biogas utilization, raw biogas and biomethane have been assessed with recently available data from the literature according to their usage areas and methods. It seems that biogas can be used as a biofuel to produce energy via CHP and fuel cells with high efficiency. Moreover, it is able to be utilized in an internal combustion engine which reduces exhaust emissions by using biofuels. Lastly, chemical production such as biomethanol, bioethanol, and higher alcohols are in the development stage for utilization of biogas and are discussed in depth. This review reveals that most biogas utilization approaches are in their early stages. The gaps that require further investigations in the field have been identified and highlighted for future research.

Abstract The accuracy of predictive models (also known as mechanistic or causal models) of animal responses to climate change depends on properly incorporating the principles of heat transfer and thermoregulation into those models. Regrettably, proper incorporation of these principles is not always evident. We have revisited the relevant principles of thermal physiology and analysed how they have been applied in predictive models of large mammals, which are particularly vulnerable, to climate change. We considered dry heat exchange, evaporative heat transfer, the thermoneutral zone and homeothermy, and we examined the roles of size and shape in the thermal physiology of large mammals. We report on the following misconceptions in influential predictive models: underestimation of the role of radiant heat transfer, misassignment of the role and misunderstanding of the sustainability of evaporative cooling, misinterpretation of the thermoneutral zone as a zone of thermal tolerance or as a zone of sustainable energetics, confusion of upper critical temperature and critical thermal maximum, overestimation of the metabolic energy cost of evaporative cooling, failure to appreciate that the current advantages of size and shape will become disadvantageous as climate change advances, misassumptions about skin temperature and, lastly, misconceptions about the relationship between body core temperature and its variability with body mass in large mammals. Not all misconceptions invalidate the models, but we believe that preventing inappropriate assumptions from propagating will improve model accuracy, especially as models progress beyond their current typically static format to include genetic and epigenetic adaptation that can result in phenotypic plasticity.

Bervie Braes is a 750 m long, and up to 55 m high, coastal slope above a residential area and harbour in Stonehaven, Scotland, with a history of instability mostly associated with the road traversing the slope. This paper outlines the most probable causes of the instability on the slope and details the hazards that had to be taken into account during the design and construction of stabilisation measures. The hazards associated with hydrology in terms of future potential change in rainfall patterns and intensity, but also in terms of providing adequate drainage capacity and flows, were juxtaposed against the geotechnical hazards of shallow landslips and erosion near the surface, as well as deep-seated landslides on the slope. Owing to the complex nature of the hazards and the need for longer life expectancy of the design, the soil nailing option was combined with eco-engineering strategies to provide resilience for a changing climate. A risk-based approach considering the number of lives at danger during a catastrophic failure was adopted when deciding on the priority of the areas of the slope to be stabilised. The sustainability of the design solution and the construction methods were constantly monitored and re-appraised throughout the project.

AbstractTropical glacier melt provides valuable water to surrounding communities, but climate change is projected to cause the demise of many of these glaciers within the coming century. Understanding the future of tropical glaciers requires a detailed record of their thicknesses and volumes, which is currently lacking in the Northern Andes. We calculate present-day (2015–2021) ice-thicknesses for all glaciers in Colombia and Ecuador using six different methods, and combine these into multi-model ensemble mean ice thickness and volume maps. We compare our results against available field-based measurements, and show that current ice volumes in Ecuador and Colombia are 2.49 ± 0.25 km3and 1.68 ± 0.24 km3respectively. We detected no motion on any remaining ice in Venezuela. The overall ice volume in the region, 4.17 ± 0.35 km3, is half of the previous best estimate of 8.11 km3. These data can be used to better evaluate the status and distribution of water resources, as input for models of future glacier change, and to assess regional geohazards associated with ice-clad volcanoes.

Abstract Fuel cell technology has undergone extensive research and development in the past 20 years. Even though it has not yet made a commercial breakthrough, it is still seen as a promising enabling technology for emissions reduction. The high electrical efficiency (Powell et al., 2012, “Demonstration of a Highly Efficient Solid Oxide Fuel Cell Power System Using Adiabatic Steam Reforming and Anode Gas Recirculation,” J. Power Sources, 205, pp. 377–384; Föger and Payne, 2014, “Ceramic Fuel Cells BlueGen—Market Introduction Experience,” 11th European SOFC & SOE Forum 2014, Lucerne, Switzerland, Paper No. A0503; and Payne et al., 2009, “Generating Electricity at 60% Electrical Efficiency From 1-2 kWe SOFC Products,” ECS Trans., 25(2), pp. 231–240) of an solid oxide fuel cell (SOFC)-based fuel cell system and the ability to operate on renewable fuels make it an ideal platform for transition from fossil-fuel dependency to a sustainable world relying on renewable energy, by reducing emissions during the transition period where fossil fuels including natural gas remain a major source of energy. Key technical hurdles to commercialization are cost, life, and reliability. Despite significant advances in all areas of the technology cost and durability targets (Papageorgopoulos, 2012, “Fuel Cells, 2012 Annual Merit Review and Peer Evaluation Meeting,” U.S. Department of Energy, Washington, DC, accessed May 14, 2012, http://www.hydrogen.energy.gov/pdfs/review12/fc_plenary_papageorgopoulos_2012_o.pdf) have not been met. The major contribution to cost comes from tailor-made balance of plant (BoP) components as SOFC-based systems cannot be optimized functionally with off-the shelf commercial items, and cost targets for BoP and stack cannot be met without volume manufacturing (Föger, 2008, “Materials Basics for Fuel Cells,” Materials for Fuel Cells, M. Gasik ed., Woodhead Publishing, Cambridge, UK, pp. 6–63). Reliability issues range from stack degradation and mechanical failure and BoP component failure to grid-interface issues in a grid-connected distributed generation system. Resolving some of these issues are a key to the commercial viability of SOFC-based microcombined heat and power (CHP) systems. This paper highlights some of the technical and practical challenges facing developers of SOFC-based products.

Efforts to protect tropical ecosystems aim at implementing biological corridors across the national territory of Costa Rica. However, potential near-future climate change challenges the effectiveness of such conservation measures. For this purpose, we developed near-future climate change scenarios at high spatial resolution using open-access global data from the Copernicus Climate Data Store (CDS). These projections resulted from downscaling (to a 1km2 national grid) and quantile-mapping bias-correction of the Essential Climate Variables Global Circulation Model (ECV_GCM) ensemble mean from the CDS using a moderate Representative Concentration Pathway 4.5 (RCP4.5). Projections were evaluated with limited local station data and applied to generate future ecosystem indicators (Holdridge Life Zones, HLZs). We show significantly increasing temperatures of 2.6°C with a spatial variability of ± 0.4°C for Costa Rica until 2040 with local differences (higher temperatures projected for the southern Costa Rican Caribbean). The future mean annual precipitation showed slightly wetter conditions (120 ± 43 mm/year) and most prominently in the Costa Rican Caribbean and south Pacific, but no significant drying in the north of Costa Rica by 2040. The bias-corrected climate data were aggregated to decadal and 30-year average (1971–2040) life zone ecosystem indicators that could potentially show ecosystem shifts. Changes in the life zones are most likely due to warmer temperatures and to a lesser extent caused by projected wetter conditions. Shifts are more likely to occur at higher elevations with a potential loss of the sub-tropical rainforest ecosystem. The projections support diminishing tropical dry forests and slightly increasing tropical rain and wet forests in the biological corridors of the driest and wettest regions, respectively. A countrywide spatial uniformity of dominating tropical moist forests (increase from 24% to 49%) at the expense of other HLZs was projected by 2040.