An Exploration of the Relationship between Socioeconomic and Well‐Being Variables and Household Greenhouse Gas Emissions

Identifying a sustainable rice-based cropping system via on-farm evaluation of grain yield, carbon sequestration capacity and carbon footprints in Central China

Whole-farm systems modelling of greenhouse gas emissions from pastoral suckler beef cow production systems

Carbon footprint of a conventional wastewater treatment plant: An analysis of water-energy nexus from life cycle perspective for emission reduction

Devising policies for a low carbon city requires a careful understanding of the characteristics of urban residential lifestyle and consumption. The production-based accounting approach based on top-down statistical data has a limited ability to reflect the total greenhouse gas (GHG) emissions from residential consumption. In this paper, we present a survey-based GHG emissions accounting methodology for urban residential consumption, and apply it in Xiamen City, a rapidly urbanizing coastal city in southeast China. Based on this, the main influencing factors determining residential GHG emissions at the household and community scale are identified, and the typical profiles of low, medium and high GHG emission households and communities are identified. Up to 70% of household GHG emissions are from regional and national activities that support household consumption including the supply of energy and building materials, while 17% are from urban level basic services and supplies such as sewage treatment and solid waste management, and only 13% are direct emissions from household consumption. Housing area and household size are the two main factors determining GHG emissions from residential consumption at the household scale, while average housing area and building height were the main factors at the community scale. Our results show a large disparity in GHG emissions profiles among different households, with high GHG emissions households emitting about five times more than low GHG emissions households. Emissions from high GHG emissions communities are about twice as high as from low GHG emissions communities. Our findings can contribute to better tailored and targeted policies aimed at reducing household GHG emissions, and developing low GHG emissions residential communities in China.

Well-to-wheel greenhouse gas emissions of electric versus combustion vehicles from 2018 to 2030 in the US

Analyzing greenhouse gas emissions from municipal wastewater treatment plants using pollutants parameter normalizing method：a case study of Beijing

Blame the exurbs, not the suburbs: Exploring the distribution of greenhouse gas emissions within a city region

Highlights Direct greenhouse gas (GHG) emissions were measured in a decoupled aquaponics system. Solids concentration predicted methane emissions in the clarifier system. Lower pH in the plant system increased N2O emissions. Higher fish feeding rate increased CO2 and N2O emissions in the plant production system. Roughly half of direct GHG emissions were offset by carbon uptake during plant growth. Abstract. Agricultural production systems are known to be large contributors to global greenhouse gas (GHG) emissions and many studies have focused on the mitigation of GHG emissions from open-field and other traditional crop production practices. Little attention has been given to direct emissions from non-traditional production systems such as aquaponics. Here we determine direct GHG emissions (CO2, CH4, N2O) from a pilot-scale biofloc, decoupled aquaponics facility. We also determine how emissions from unit operations differ based on a set of environmental and operational parameters e.g. temperature, feeding rate, suspended solids, plant height, water flow rate, and nitrate levels. Major unit operations included a biofloc fish tank stocked with tilapia, a solids settling clarification system, and a climate-controlled greenhouse in which cucumber plants were grown in substrate culture. The study was separated into three seasons. In the summer of 2019, different pH treatments for cucumber irrigation water were tested. In the fall of 2019 and winter of 2020, emissions from perlite versus pine bark substrates were tested during cucumber production. Measurements indicated that aerial GHG emissions in intensively aerated areas of the fish tank were 4.7 to 46.8 times higher than those in areas with low-intensity aeration. High methane emissions (up to 44.8 g m-2 d-1) from the clarification system indicated anaerobic activity. Results from plant production showed a negative relationship between pH and N2O efflux (p=0.0001) while the choice of plant growth substrate had no significant effect on direct GHG emissions. Overall, carbon sequestration in plants could offset 40% to 62% of direct GHG emissions from the aquaponics system. This study provides insight into operational parameters that affect direct GHG emissions from aquaponics systems and provides data to support life cycle assessments. Keywords: Aquaculture, Carbon dioxide, Hydroponics, Methane, Nitrous oxide.

Climate-smart livestock production at landscape level in Kenya

A plant-wide wastewater treatment plant model for carbon and energy footprint: Model application and scenario analysis

Reply to L Aleksandrowicz et al.

Greenhouse gas (GHG) arising from the treatment of domestic sewage in the developed world is known to contribute to GHG emissions in the atmosphere – principally carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Accounting protocols exist that allow development of emissions inventories on a geographic, utility, or facility-specific basis using uniform methodologies and assumptions. This thesis develops new, improved methodologies for estimating direct GHG emissions sources from: 1) Sewer CH4, 2) Anthropogenic CO2 from methanol use for nutrient removal, and 3) CH4 from incomplete digester gas combustion. The significance of these GHG sources is estimated herein on a national scale for centralized wastewater treatment in the United States (US). Current GHG-emissions-inventorying protocols consistently ignore sewer CH4.However, by the methods in this thesis, sewer CH4 is estimated to represent between 26% and 35% of DC Water’s and more than 54% of centralized-wastewater-related direct GHG emissions in the US. A new sewer CH4 methodology developed in this thesis uses sewer hydraulic models at average flow rates to classify pipe segments as either gravity or surcharged sewers. CH4 generation in surcharged segments is derived using a prior forcemain algorithm while gravity sewers are modelled using a new algorithm. After method verification using exhaust-CH4 mass fluxes from an odour-control fan evacuating air from a regional sewer, the methodology is applied to the entire DC Water (Washington, DC - US) collection system to estimate utility-wide sewer CH4 emissions, which are found to be substantial.Similarly, until recently, GHG-accounting protocols also ignored CO2 emissions attributable to methanol addition for nutrient removal. As most methanol is derived from natural gas, its carbon represents an anthropogenic CO2 emission when released. In this thesis, a site-specific method is developed for DC Water and used to determine that methanol CO2 represents 40% and 60% of DC Water’s direct GHG emissions, before and after anaerobic-digestion upgrades, respectively. When applied to the US treated wastewater flows, considering likely effluent-nitrogen requirements and presence of and/or lack of digestion that would influence methanol use, methanol CO2 is estimated to account for nearly 12% of the country’s centralized-wastewater-treatment GHG emissions.A new method is also developed to account for fugitive CH4 from digester-gas combustion based on a specific end uses of the biogas. This method contrasts with current protocols which uniformly suggest that 1 to 2% of all produced digester gas is vented to the atmosphere (whether through incomplete combustion or simply leakage is unclear). Use of the new methodology could, depending on the biogas-use technologies in operation, more accurately replace a 1% protocol-based estimation of 4,200 MT CO2e/year for DC Water with emission rates ranging from 60 to over 21,000 MT CO2e/year. Accordingly, current protocol-based simplifications are shown to result in an actual 70-time overestimation for DC Water or a possible 5-times underestimation for the poorest-efficiency biogas-combustion devices: conventional, candle-stick flares.As the final subject of this thesis, electricity use, which comprises the largest portion of centralized-treatment GHG emissions inventories, is reviewed. GHG emissions from electricity consumption occur at the power plant, and their make-up and carbon intensity is a function of how that plant produces electricity. While local electricity carbon intensity is normally beyond the control of the wastewater utility, how much is purchased is largely under its control. Aeration-blower and total-plant power consumption over one or two years for 13 large to very-large facilities in New York City (NY - US) are correlated to average flow and total-oxygen-demand loading and removal to evaluate electricity-use metrics. Additionally, the local carbon intensity of power is shown to dramatically impact the magnitude of GHG emissions and to have surprising effects on an example “sustainability-enhancing” upgrade.This research discusses these improved GHG-accounting methodologies and evaluates their significance using large-scale utility process and GHG data. When combined, application of new sewer CH4 and methanol CO2 methods herein would roughly triple direct GHG emissions attributed to an industry that already represents a significant GHG source and energy consumer. An improved understanding of emissions intensity and the significance of various emissions sources would allow an already proactive wastewater industry to better target or incorporate intervention strategies that mitigate GHG emissions. This thesis offers these improved methodologies while providing evidence that: 1) GHG accounting science is far from fully understood; 2) additional research is warranted; so that 3) the industry’s understanding and GHG emissions baselines are accurate and thereby support almost-certain eventual regulation.

The structural transition to a service economy has clearly contributed to decreasing direct (or territorial) greenhouse gas emissions. Nevertheless, the role of this structural transition on direct greenhouse gas emissions is not well understood quantitatively. This study applied the additive decomposition method and decomposed the change in CO2 emissions from domestic industries into five components: changes in the overall scale of the economy, changes in the industrial composition of the various economic sectors, energy intensity changes, changes in import composition, and changes in the import scale. The decomposition results show that during the 15-year period from 1990 to 2005, structural change effects under the domestic technology assumption (which include industrial composition effects, import scale effects, and import composition effects) totaled −35 Mt CO2, or 3 % of total CO2 emissions in 1990. It is concluded that the CO2 reduction due to the transition to a service economy was not negligible during 1990–2005 and that the structural transition to a service economy was much more important than the material dependence of service industries. JEL Classification: O14, O44, Q56.

The decarbonisation of the construction sector is critical to meet national and international climate goals. Literature gives many examples of measures for the reduction of greenhouse gas (GHG) emissions from buildings. However, few studies investigate the trade-offs between potentially conflicting GHG emission reduction measures or the affordability of these measures. Ydalir is a Zero Emission Neighbourhood (ZEN) pilot area in the Norwegian research centre for Zero Emission Neighbourhoods in smart cities. One of the major challenges Ydalir faces is how to reduce GHG emissions from the neighbourhood towards a net zero emission building (nZEB). Additional challenges include retaining social, environmental, and economical sustainability for both the project developer and building owners and avoid suboptimal solutions. This paper investigates the trade-offs between energy efficiency and material use for two scenarios. The scenarios are a Norwegian building code scenario and a passive house scenario. The analysis ascertains total energy demand, whole life cycle GHG emissions, and cost assessment for two housing units within Ydalir Torg. The results show lower total GHG emissions and lower GHG emissions from operational energy use in the passive house scenario, and an increase in GHG emissions from the production phase due to thicker levels of insulation. The cost assessment shows increased investment costs for the project developer in the passive house scenario, despite lower operational costs for the building owner. Total GHG emission payback times for the passive house scenario are at 18 - 19 years. Cost payback time varies between 10 - 37 years. This paper is useful for practitioners that wish to balance GHG emission reduction requirements between operational energy use, material use and affordability.

Polyethylene film mulch (PM) is a kind of widely used technology to improve crop yields worldwide; however, because of a problem related with plastic residual pollution, it has gradually been replaced by biodegradable plastic film mulch (BDP). Although BDP has helped to solve the plastic residual pollution, its consequences in terms of greenhouse gas (GHG) emissions have rarely been revealed. Related knowledge is important for forming low-carbon development strategies for the plastic industry and agriculture. The objective of this study is to evaluate the influence of BDP on GHG emissions at different stages of its life cycle, and determine whether replacing polyethylene (PE) film with BDP film is a helpful way to reduce national GHG emissions. The results of this study suggest that the application of BDP improved the GHG emissions associated with agricultural inputs, but induced lower GHG emissions at the growing stage and the waste disposal stage, and resulted in lower total area-scale GHG emissions. Compared to the no mulch (NM) cultivation system, the yield-scale carbon footprint was reduced in both the PM and BDP cultivation systems, which meant that both PM and BDP produced lower GHG emissions than NM for the production of the same amount of grain. It was concluded that BDP is not only a measure to control the problem of plastic residue pollution in agriculture, but it can also mitigate the GHG emissions.