Effect of Ornamental Stone Waste Incorporation on the Rheology, Hydration, Microstructure, and CO2 Emissions of Ordinary Portland Cement

The ornamental stone industry generates large amounts of waste thus creating environmental and human health hazards. Thus, pastes with 0–30 wt.% ornamental stone waste (OSW) incorporated into ordinary Portland cement (OPC) were produced and their rheological properties, hydration kinetics, and mechanical properties were evaluated. The CO2 equivalent emissions related to the pastes production were estimated for each composition. The results showed that the paste with 10 wt.% of OSW exhibited similar yield stress compared to the plain OPC paste, while pastes with 20 and 30 wt.% displayed reduced yield stresses up to 15%. OSW slightly enhanced the hydration kinetics compared to plain OPC, increasing the main heat flow peak and 90-h cumulative heat values. The incorporation of OSW reduced the 1-, 3-, and 28-days compressive strength of the pastes. Water absorption results agreed with the 28 days compressive strength results, indicating that OSW increased the volume of permeable voids. Finally, OSW incorporation progressively reduced the CO2 emission per m3 of OPC paste, reaching a 31% reduction for the highest 30 wt.% OSW content. Overall, incorporating up to 10 wt.% with OSW led to pastes with comparable fresh and hardened properties as comported to plain OPC paste.

Rice quality and its impacts on food security and sustainability in Bangladesh

Rice market efficiency is important for food security in countries where rice is a staple. We assess the impact of rice quality on rice prices, food security, and environmental sustainability in Bangladesh. We find that while price varies as expected for most quality attributes, it is unaffected by a broken percentage below 24.9 percent. This reveals a potential inefficiency, considering the average 5 percent broken rate observed in the market. An increase in the broken rate of milled rice within the limits supported by our findings can, ceteris paribus, increase rice rations by 4.66 million a year, or conversely, yield the current number of rice rations using 170.79 thousand fewer hectares and cutting emissions by 1.48 million metric tons of CO2 equivalent. Thus, producing rice based on quality assessment can improve food security and its sustainability.

Internalizing CO2-Equivalent Emissions Issued From Agricultural Activities

The aim of this article is to consider the market-based instruments, such as the ETS system, for the internalization of the CO2-equivalent emissions issued from the agricultural sector. We use a hypothetical market valuation of the emissions and we extend the analysis to the optional pricing with double barriers. According to our results, the purpose of attaining the levels of carbon emissions recommended by the French public authorities, with a level of reductions down by 50.00% in 2030, could be successful would the terminal range of optional prices stand between 76.35 and 89.56 Eur.

Sustainable Consumer Behavior and Food Marketing

The global food system accounts for emissions amounting up to 18 Gt CO2 equivalent per year, representing 34% of total GHG emissions [...]

Study of Biogas Production from Organic Waste through the Implementation of Biodigestors

Biogas is considered as a gaseous tributary of the anaerobic digestion of agro-industrial waste, a boiler, it can be burned in combustion engines to generate electricity and heat through cogeneration. Biodigesters responsible for producing energy with a content of 1 m3 of biogas (60% CH4 and 40% CO2) equivalent to 6 kWh / m3. It undergoes a purification its composition will depend not only on the technology used for the process but also on the treated substrate. Its methane composition varies between 50 and 70% and present between 30 and 40% CO2 and less than 5% hydrogen (H2) and other gases. The calorific value of biogas is associated with the composition of the methane it has. Biogas is a very versatile source of energy, it can be transformed into thermal energy through the use of process eliminating hydrogen sulfide and other contaminants from the membranes, it can be used as fuel, purifying and adding the necessary additives, it can be transformed into biomethane, a compound with characteristics very similar to natural gas. Biogas can be used as an electricity generator or as a heat producer if both sources of energy are generated, we speak of a cogeneration process, the electricity produced by generation can be injected into the electricity grid or consumed by the industry that generates the waste.

Integrated Cycles for Urban Biomass as a Strategy to Promote a CO2-Neutral Society—A Feasibility Study

The integration of closed biomass cycles into residential buildings enables efficient resource utilization and avoids the transport of biowaste. In our scenario called Integrated Cycles for Urban Biomass (ICU), biowaste is degraded on-site into biogas that is converted into heat and electricity. Nitrification processes upgrade the liquid fermentation residues to refined fertilizer, which can be used subsequently in house-internal gardens to produce fresh food for residents. Our research aims to assess the ICU scenario regarding produced amounts of biogas and food, saved CO2 emissions and costs, and social–cultural aspects. Therefore, a model-based feasibility study was performed assuming a building with 100 residents. The calculations show that the ICU concept produces 21% of the annual power (electrical and heat) consumption from the accumulated biowaste and up to 7.6 t of the fresh mass of lettuce per year in a 70 m2 professional hydroponic production area. Furthermore, it saves 6468 kg CO2-equivalent (CO2-eq) per year. While the ICU concept is technically feasible, it becomes economically feasible for large-scale implementations and higher food prices. Overall, this study demonstrates that the ICU implementation can be a worthwhile contribution towards a sustainable CO2-neutral society and decrease the demand for agricultural land.

Guest Editorial: The Engineering Approach to Carbon-Emissions Management

Every engineer and manager knows that you can only improve performance that you measure and track. That is why we have key performance indicators (KPIs). Similarly, we can only optimize what we can predict. If we really want to lower carbon emissions, we will need to implement a consistent method of measuring and tracking the right data. There are challenges in improving what we track because tracking comes from so many sources. We need to work on optimizing what we predict if we are going to start making high-value decisions around emissions. Carbon emissions occur during all phases of the hydrocarbon extraction industry right through to the final use of the product. We call the total life cycle of emissions “well to wheels.” SPE members are generally focused on one phase of the carbon emissions. The largest contribution is the combustion and use of produced oil, from refinery to wheels. This is typically about 350–400 kg of CO2 equivalent per barrel. We use CO2 equivalent to include the greenhouse-gas (GHG) impact of methane. Then, there is the energy and carbon expenditure of producing that hydrocarbon, well to refinery. This includes drilling, completions, production, and transportation. Carbon emissions from the wells to refinery vary from less than 25 kg to more than 300 kg CO2 equivalent per barrel, aver-aging about 100. Flaring and fugitive emissions are generally the largest contributors to these emissions. Environmental, social, and governance (ESG) activism is driving changes in behavior for public investors, private investors, lenders, and management teams. When will the measuring be done? Who will set the industry standards? How will the model be developed? Carbon emissions from shale production vary dramatically and are also driven by flaring and fugitives. While flaring is preferable to venting, most low-volume flares are inefficient. Operators flare for a variety of reasons including lack of pipeline capacity, upsets, and low value for natural gas. Fugitive emissions also enter the equation. Fugitive emissions are any leakage or irregular release to the atmosphere of natural gas. This can be caused by human error, mechanical operations (such as pneumatic actuators), or faulty equipment. Fugitive emissions and flaring both factor into the well-to-reservoir carbon footprint. Many operators already report the carbon intensity of their activities, usually prior-year activities. Carbon intensity is the carbon emissions per unit of energy or per barrel. A variety of regulatory bodies and others argue the definitions of such reporting. We are arguing for reporting estimated carbon intensity of reserves.

CO₂-equivalence metrics for surface albedo change based on the radiative forcing concept: a critical review

Management of Earth's surface albedo is increasingly viewed as an important climate change mitigation strategy both on (Seneviratne et al., 2018) and off (Field et al., 2018; Kravitz et al., 2018) the land. Assessing the impact of a surface albedo change involves employing a measure like radiative forcing (RF) which can be challenging to digest for decision-makers who deal in the currency of CO2-equivalent emissions. As a result, many researchers express albedo change (Δα) RFs in terms of their CO2-equivalent effects, despite the lack of a standard method for doing so, such as there is for emissions of well-mixed greenhouse gases (WMGHGs; e.g., IPCC AR5, Myhre et al., 2013). A major challenge for converting Δα RFs into their CO2-equivalent effects in a manner consistent with current IPCC emission metric approaches stems from the lack of a universal time dependency following the perturbation (perturbation “lifetime”). Here, we review existing methodologies based on the RF concept with the goal of highlighting the context(s) in which the resulting CO2-equivalent metrics may or may not have merit. To our knowledge this is the first review dedicated entirely to the topic since the first CO2-eq. metric for Δα surfaced 20 years ago. We find that, although there are some methods that sufficiently address the time-dependency issue, none address or sufficiently account for the spatial disparity between the climate response to CO2 emissions and Δα – a major critique of Δα metrics based on the RF concept (Jones et al., 2013). We conclude that considerable research efforts are needed to build consensus surrounding the RF “efficacy” of various surface forcing types associated with Δα (e.g., crop change, forest harvest), and the degree to which these are sensitive to the spatial pattern, extent, and magnitude of the underlying surface forcings.