Internalisation of environmental costs of decentralised nitrogen fertilisers production.

Purpose: Ammonia (NH3) production is an energy-intensive process that is concentrated in a few countries at large-scale plants, mainly using the Haber-Bosch (HB) process. Local plants next to farmers can reduce environmental impacts, as well as reduce storage, shortage risks, and price volatility of fertilisers. Since local NH3 production is not cost-effective, we analyse how internalisation of environmental impacts into economic analyses could help to promote novel technologies for NH3 synthesis when supplied with renewable energy. Methods: Mini-HB plants working at high pressure and temperature, as well as novel alternatives based on plasma reactors working at ambient conditions and using electricity from renewable sources, have been recently proposed for decentralised NH3 production. To evaluate the environmental performances of these alternative and traditional NH3 pathways, a life cycle assessment was performed to quantify the reduced emissions in each production process and the impacts of by-product utilisation, such as steam, oxygen, or carbon black. Different scales of storage and transportation, fuelled by traditional energy sources, were modelled to quantify the impacts of the simplified NH3 supply chains. A review of monetary valuation coefficients was performed to internalise the life cycle environmental impacts into the techno-economic analyses of NH3 production in Australia. Results and discussion: Most of the estimated environmental costs were due to the carbon emissions of conventional plants and thermal plasma plants because of the use of fossil-based electricity. However, the high external costs associated with the photochemical oxidant formation and particulate matter affected the thermal plasma and non-thermal plasma (NTP) plants, costing in total 9,500 and 4,200 $/t NH3, respectively, due to the impacts of solar panels manufacturing. In contrast, electrolyser-HB plants obtained rates of 114 $/t NH3 because of the high energy efficiency and oxygen sales. In the future scenario for NTP-based plants, this alternative could also be competitive with rates of 222 $/t NH3. Additionally, the estimated total external costs for the conventional NH3 industry in Australia amounted to about US$5 billion per year. Conclusions: Electrolyser-HB plants could be cost-effective in the short term due to the energy efficiency of HB processes. However, the HB process has reached its efficiency limits, while the NTP process still has room for improvement, as well as its production costs are lower at smaller scales. In addition, if monetised environmental costs are analysed for a whole industry, public administrations could be prompted to invest the expected savings in the promotion of these novel technologies. Supplementary Information: The online version contains supplementary material available at 10.1007/s11367-023-02187-5.

Comparative life cycle assessment for the manufacture of bio-detergents.

The increasing consumption of cleaning products deteriorates water resources due to harmful components such as phosphorus (P) and nitrogen (N) compounds, oils, bleach, and acids, typical compounds in traditional detergents. The use of biodegradable detergents as an environmentally friendly alternative has been proposed in different regions. In Colombia, resolution 1770/2018 sets a minimum biodegradability rate of 60% for the surfactants present in liquid detergents, which would reduce to a similar extent the impacts on water after their use. However, the environmental impacts of the supply chain of these detergents and their raw materials have not been evaluated so far. This study presents an environmental life cycle assessment of petroleum-based liquid detergents and a comparison to traditional solid detergents, based on the ISO 14040 standard and the ReCiPe-2016 impacts assessment method. A novel bio-detergent containing anionic plant-based surfactants was proposed in this analysis. The impacts of packaging and the distribution of the product to consumers were also considered. Raw materials contributed to 91% of the total of 314 g of CO2 eq generated per liter of liquid detergent, where the production of fatty alcohol sulfate and PET packaging shared 78.8% and 12.2% of the total impact, respectively. It was also determined that 5.4 L of water are consumed and 0.09 g of P eq and 0.1 g of N eq are emitted per liter of detergent. This liquid detergent presented better environmental performance than traditional detergents in all the impact categories, except for the fossil resource scarcity category. The evaluated detergent would significantly mitigate the generation of negative effects on ecosystems. Moreover, the substitution of PET for HDPE packaging could reduce the impacts on freshwater eutrophication by 10%, although the carbon footprint can slightly increase, which could be compensated due to its higher recyclability rate. In contrast, the proposed bio-detergent would not have significant benefits and would negatively affect water consumption and land use in its supply chain.

Comprehensive Water Footprint of a University Campus in Colombia: Impact of Wastewater Treatment Modeling.

Protection of water resources implies the responsible consumption, and the return of this resource with the best physicochemical conditions. In organizations, water is consumed both directly in their facilities and indirectly in the products or services acquired for their operation, requiring a water accounting based on the life cycle perspective. This study aims to assess the comprehensive water footprint of the main campus of the Technological University of Pereira (Colombia), based on the ISO 14046:2014 standard, and analyze the influence of wastewater treatment. Impacts on water scarcity were evaluated using the AWARE method, while the impacts on human health and ecosystems were evaluated using the ReCiPe method. Specific modeling of the wastewater treatment plants on campus was conducted. A total of 102,670 m3.y-1 of water scarcity was accounted for. Water consumption per person was 17.8 m3 of which 86.2% corresponded to indirect activities. Similarly, indirect activities were responsible for more than 98% of the impacts on human health and ecosystems, where more than 95% were due to infrastructure construction and 2% due to electricity consumption. Although the wastewater treatment on campus reduced the impact on ecosystems by 14%, if a tertiary treatment was added, these impacts would have a 40% of additional reduction. Efforts in recycling programs were also quantified in 712 m3 of avoided water scarcity for secondary users. The findings suggest focusing actions on sustainable construction and purchases to improve water management in organizations.