Contributions of Chemical Engineering to Sustainability

While aiming to end hunger, food safety is essential to food security. This should be sought at the different levels of the food processing chain to guarantee that food reaches consumers free of contaminants. There are many potential points of food contamination with spoilage-prompt, opportunist, or pathogenic organisms, as well as chemical substances or hazards during food processing. Focusing on food microbial safety at post harvesting stage, many different emergent techniques have been studied for food preservation with varying degrees of processing. Low-pressure ultraviolet light (UV-LP), ultraviolet light-emitting diodes (UV-LEDs), and pulsed light (PL) treatments are non-thermal technologies that use ultraviolet radiation in different arrangements and electromagnetic wavelengths for the inactivation of microorganisms in food systems. Even though each of them has advantages and disadvantages in their large-scale application for processing liquid foods, several studies have demonstrated the potential of these technologies to replace traditional pasteurization treatments. Their effectiveness depends on the characteristics of the sample matrix and the optimization of the operating parameters. Moreover, the effect of equipment configuration on the treatment effectiveness and the synergistic effect among UV radiation when combined with thermal and non-thermal treatments has been recognized. Novel equipment designs and the implementation of regulation for industry regulations of these treatments promise to be an efficient technology for liquid food processing, which can help meeting the 2030 agenda’s goal of diminuish population’s malnutrion.

The Food and Agriculture Organization of the United Nations (FAO/UN) estimates that the world’s population will exceed 9.1 billion people by 2050. The food demand required for this population is looming as a gigantic challenge. The sufficiency of foods rich in high biological value proteins will be a priority due to their importance in the proper physical and mental development of people. In this scenario, entomophagy, the consumption of insects as a nutrient source, is a viable food alternative that is well aligned with the principle of sustainability. Edible insects, as an unconventional food source, offer a unique opportunity to address the pressing issues of food security and environmental conservation, as their breeding offers significant advantages such as low space and time requirements, independence from cereals for feeding, lower CO₂ emissions, and lower water and land use for growth. In addition, there is a growing interest in their techno-functional properties in order to use them as food ingredients. Moreover, their beneficial effects on consumer health derived from various components make insect breeding an efficient and sustainable option. This chapter critically reviews the opportunities offered by insect consumption to ensure food sufficiency, highlighting their nutritional benefits, positive effects on consumer health, and additional applications in the food industry, thereby positioning edible insects as a unique and multifaceted solution to address the pressing issues of food security and environmental conservation.

Emerging global trends, such as rapid urbanization and climate change, put further pressure on already scarce water resources. Water and sanitation utilities, as important service providers, play a key role to “ensure availability and sustainable management of water and sanitation for all”, Goal 6 of the United Nations Sustainable Development Goals (SDG 6). To help achieve SDG 6, water utilities need to increase their productivity and become more efficient. This will require tapping into new approaches, technologies, and solutions to meet emerging needs. Consequently, the role of chemical engineers in the water and wastewater treatment field is becoming more critical, as their expertise is needed to develop materials, technologies and design multistep processes required to treat water from complex streams and sources. In this chapter, we present a review on recent advancements in technologies for wastewater treatment. Research trends and innovation in physical, chemical, and biological processes for wastewater treatment are discussed. Current gaps and barriers are also identified. Moreover, the contribution of chemical engineers to the generation of knowledge in the field is evaluated. While chemical engineers have consistently contributed to the improvement of water and wastewater treatment processes, other disciplines are contributing in greater proportion to clean water and sanitation research. However, chemical engineering research seeking technological strategies to improve sanitation and water quality can be an essential component in the efforts to reach SDG 6.

There is a considerable variety of research on microalgae-based wastewater treatment systems (MWWTS). This chapter discusses the diverse microbial associations that have been applied to MWWTS as well as the role of other biological players, such as zooplankton and viruses. Although microalgal-bacterial associations are widely studied, others such as microalgal-fungal are now receiving increasing attention. The metabolisms of photosynthetic microalgae and aerobic bacteria complement each other, increasing the overall efficiency of MWWTS. Statistical meta-analyses of the literature data indicate that microalgal-bacterial and microalgae-only wastewater treatment systems remove significantly different percentages of COD (paired t-test, t₂₁ = 4.138, P < 0.001), TN (paired t-test, t₁₀ = 3.61, P = 0.004), and TP (paired t-test, t₁₅ = 2.37, P = 0.031). Meanwhile, microalgae and fungi are readily pelletized and accumulate large amounts of lipids, which can be used for biofuel production. On the other hand, zooplankton and viruses can also be present in MWWTS, interacting with the implemented consortia. The presence of zooplankton communities can compromise MWWTS; however, several zooplankton control techniques have been studied and are effective at optimizing the MWWTS process. Regarding aquatic viruses in MWWTS, more research should be conducted given the roles of virioplankton and their interactions with microalgae in naturally occurring water bodies. Independently of the important roles of different organisms (aerobic-anaerobic) on wastewater treatment, the presence of other microorganisms such as microalgae improves different wastewater treatment processes. Thus, more research is needed on the use of different microalgae, bacteria and fungi species to enhance the removal of different pollutants (including toxic and persistent compounds) and micronutrients, while providing oxygen to the system and consuming CO₂, reducing the need for mechanical aeration and fixing CO₂ from the environment.

Due to the low cost, accessibility, and low greenhouse gas emissions associated with the use of biomass to produce energy and bioproducts, it has become a promising alternative to the industry. The bioprocesses in the biorefinery concept framework as a route the biomass valorization, present a main advantage of reducing fossil fuel dependency. In this context, this chapter presents a review of the current situation of biomass. Also, the public policies that are being implemented in Latin American countries around the use of biomass and the implementation of bioprocesses and biorefineries are described and analyzed. Biorefineries schemes based on rice straw and rice husk are proposed and analyzed (Scenario 1: rice straw fermentation – rice husk pyrolysis and Scenario 2: rice husk fermentation and rice straw pyrolysis). Both assessed scenarios were feasible. The economic margins were 9.22%, and 24.62% for scenarios 1 and 2, respectively. The pyrolysis process subsidizes the fermentation process and improves the biorefineries’ economic performance. Biorefineries as sustainable productive models contribute to meeting the Sustainable Development Goals (SDG's) 7, 8, 9, and 13. The biorefineries as sustainable productive models contribute to meeting the SDG and the materialization of addressing the current economic system to a bioeconomy.

Desalination techniques, especially solar water distillation, present a viable solution for tackling freshwater scarcity and purifying contaminated water. However, the limited output of solar stills is a challenge for their broad application. To improve solar stills’ efficiency, various enhancements have been tested, such as employing interfacial vapor generation and phase change materials. This chapter discusses the evolution of a double-sloped solar still enhanced with these materials to boost water production. The study concentrates on a specific endeavor to create an affordable, sustainable solar desalination system in Guanajuato, in line with Sustainable Development Goals 6 and 7. By refining the evaporation system with porous and absorbent substances like cellulose combined with Biochar and polymer, notable progress in interfacial vapor generation was made. Testing various materials in a prototype showed that integrating a phase change material and interfacial vapor generation material significantly increased the production rate to up to 5.84 L/day of drinkable water. This research aids in advancing sustainable solar desalination technologies, which are crucial for addressing global water scarcity, particularly in sun-rich areas like Guanajuato.

Cocoa beans and coffee husks, abundant and calorific biomass resources, hold significant promise. Fast pyrolysis offers a pathway to extract high-value products from these sources. Leveraging biomass aligns with UN Sustainable Development Goals, promoting health, sanitation, and clean water by curbing landfill waste, while also facilitating affordable clean energy from pyrolysis by-products. This approach contributes to a circular economy, fostering industry innovation and infrastructure development in developing nations, ultimately reducing poverty. This study employs Aspen Plus software to simulate steady-state circulating fluidized bed pyrolysis of cocoa bean and coffee husks, comparing bio-oil yield and composition across four scenarios. Examining cellulose, lignin, ash, and moisture content for each biomass feedstock, the research reveals the significance of the cellulose-to-lignin ratio in bio-oil yield. Coffee husks emerge as more promising than cocoa bean husks due to enhanced levoglucosan formation. Furthermore, environmental impact assessments using OPEN LCA software, aligned with ISO 14040 and 14044 standards, demonstrate that higher yields result in lower CO₂eq emissions. This multifaceted approach underscores the potential of these biomass resources in advancing sustainable development and mitigating environmental impact.

Continuous release of polluting emissions to environment and consumption of raw materials at high rate are inevitable consequences of increasing demand for goods and services due to perpetual population rise, which may compromise the natural resources for the future generations. This concern has triggered the need to develop more sustainable processes (Schöggl et al., 2020). Such processes require modifications in the category and magnitude of the raw materials and utilities used, in the prevention and minimization of all types of polluting emissions, and in the manufacture of the required products without negatively affecting the economic, environmental, and social benefits. These sustainable considerations should be included in the planning at all stages of the industrial supply chain (e.g., product source, manufacturing plant, distribution, and disposal). Integrating sustainability in the design of processes contributes to the prevention and minimization of negative aspects in the topic of sustainability, instead of making corrective and costly modifications (Jiménez-González et al., 2012). However, one of the difficulties in quantifying the sustainability of the process lies in establishing the correct procedure to achieve better sustainability performance. Therefore, developing indicators capable of evaluating the sustainability of chemical processes becomes crucial for decision-making and progressing towards sustainable development. These indicators must have the ability to integrate complex process operations and transport phenomena into a manageable amount of quantitative information that is easy to analyze and evaluate. The sustainability approach is highly recognized as a useful tool at any scale of the processes, i.e., unit operation, process design, company, supply chain, and etc.

With the increase in global energy consumption, concern for the environment and material resources, it is imperative that the industry seeks continuous improvement of processes. The aviation sector influences this issue by the growing need for its use impacting the global economy. During 2017, more than 4.1 billion passengers and 539 million metric tons were transported, which represents about 35% of global trade by value. Besides, the number of passengers is expected to double by 2036, increasing jet fuel consumption, hence the need to implement a viable alternative to replace them in a sustainable way and with a sustainable process. There are some routes for the production of bio jet fuel, for example, hydro processing of fatty acids and esters (HEFA), (Wang et al., 2020) however its application on an industrial scale is not entirely feasible due to the direct competition with arable land. On the other hand, it is possible to start from alcohols for the production of biojet fuel through the ATJ process (Alcohol-to-jet, ATJ) which was recently certified in April 2016 by ASTM. The ATJ process consists of 4 stages starting from ethanol, (i) dehydration, (ii) oligomerization, (iii) hydrogenation, and (iv) purification. The ATJ route has bioethanol as a raw material, which has lignocellulosic agroindustrial waste as a precursor raw material that does not require additional water or long times to obtain it. However, one of the disadvantages is that it is a relatively expensive process and is still not sufficiently competitive in the market, compared to the conventional jetfuel production process. The process of obtaining biojet has been previously studied by several authors; however, it is a process with a wide field for improvement. Process intensification is a philosophy that attempts to generate better results, reducing the use of equipment, energy, resources, etc. In this sense, the use of PI strategies seems to be a promising alternative to generate a more competitive biojet production processes compared to the conventional biojet production process. The goal of this work was to design an intensified process to produce biojet fuel from Mexican lignocellulosic biomass having alcohols as intermediates. The process was modeled considering an intensified process for pretreatment/hydrolysis/fermentation/purification for the biomass-ethanol process. Also, a reactive distillation-based process for dehydration/oligomerization/hydrogenation/distillation was considered. Once designed, the entire process was optimized by employing the stochastic method of Differential Evolution with Tabu List to minimize the total annual cost and the ecoindicator-99 as objective functions to evaluate the sustainability of the process. The results show that savings of 20% in the total annual cost and a reduction of 18% in ecoindicator-99 in comparison with conventional production of biojet.

This chapter focuses on the development of a supply chain for the production of bio-jet fuel via the ATJ route, using agricultural waste from Mexico as the raw material. The objective of this study is to evaluate the feasibility and sustainability of producing biojet-fuel via this route. Economic, environmental, and social aspects were considered as objective functions to evaluate the sustainability of the process. These metrics consist of the maximization of profit, the minimization of environmental impact as measured by the Eco-indicator 99, and the equitable distribution of resources, to evaluate economic, environmental al social aspect respectively. Through comprehensive analysis, it was determined that the optimal design of the supply chain necessitates an annual financial incentive of $485 million to reach the breakeven point. Furthermore, the projected environmental impact is estimated to be 17,502 million points per year. A detailed economic analysis reveals specific areas within the ATJ process that require enhancements to ensure economic viability and cost reduction in alignment with the selling price of conventional biojet fuel. Notably, the pretreatment and sugar conversion to ethanol stages are identified as the primary bottlenecks that affect the economic feasibility of the overall process. These findings provide valuable insights into the essential improvements and cost reductions necessary to establish a sustainable and economically viable biojet-fuel production process. This findings provide valuable information in order implement this technology on an industrial scale and to address some of the goals of the 2030 Agenda, such as objectives 6, 7, 9, 12, and 13.

Bioenergy with carbon capture and storage (BECCS) is projected to be essential in the global warming mitigation strategy. However, BECCS systems are still in early development. Chemical engineering provides the knowledge for theoretically and experimentally testing innovative technologies to achieve an efficient commercial deployment. Here, a theoretical UK-based BECCS decentralized system producing hydrogen from wooden residue was evaluated using process system engineering methodology to estimate process efficiencies, supply chain environmental impacts, and sustainability performances. The assessment stages involved feedstock evaluation, technology review, process modelling and simulation, lifecycle assessment, and sustainability indicator modelling. The methodology employed revealed that utilizing UK’s domestic wooden residue could yield 1.5 to 8.1 GWh p.a. of fuel hydrogen, while offsetting −1.8 to −3.7 MtCO₂ annually, depending on the selected process configuration. Relying solely on these resources and technology would not be sufficient to meet the UK’s carbon offsetting and low-carbon hydrogen generation targets. The system had positive sustainability effects from sustainable feedstock utilization, emission reductions, and renewable energy supply (SDGs 3, 8, 11, 12, 13). Negative impacts on SDGs 7 and 9 due to higher energy prices and insufficient infrastructure were found. These studies are crucial for informing policymakers to effectively plan the low-carbon energy transition.

Carbon dioxide (CO₂) emissions contribute to important impacts in climate change and global warming. The concentration of this gas has increased up to 400 ppm in the last years. The most contributing sectors to the CO₂ accumulation in the atmosphere are the manufacturing and energy industries. The most important effect of CO₂ releases is the constant increase of the global temperature of the Earth. The United Nations have stablished the Sustainable Development Goals (SDGs) as a strategy to improve the sustainability of society involving different issues such as poverty and human well-being, sustainable production and consumption, and natural resource use. Specifically, CO₂ capture, storage, and utilization (CCSU) technologies contribute to the accomplishment of the SDG12 “Responsible consumption and production” and the SDG13 “Climate action”. International organizations have joined and are committed to measure greenhouse gases concentrations and to operate with neutral emissions according to the SDGs by avoiding the Earth warming and ocean acidification. Within the Carbon Capture and Storage (CCS) existing technologies to utilize CO₂, post-combustion capture, pre-combustion capture, and oxyfuel combustion have been studied to achieve a clean production. The CO₂ can be destined for valorization alternatives at different production scales to produce dimethyl carbonate (DMC), sodium bicarbonate (SB), and glycerol carbonate (GC). Moreover, the CO₂ can also be destined as gasifying agent to obtain cold gas rich in carbon monoxide and methane. Regarding the emerging interest to capture and upgrade CO₂ and the use of renewable resources (i.e., biomass) to obtain value-added products and energy vectors, this chapter aims to provide a review of the existing alternatives concerning to CO₂ capture and utilization. In addition, this chapter analyzes the routes of CO₂ transformation and the possible integration with existing biomass upgrading processes in the Colombian context. For this, two study cases are presented. The first study case involves the emitted CO₂ upgrading after biogas obtaining and combustion in the starch extraction process using cassava as raw material. The second study case considers the emitted CO₂ upgrading from molasses fermentation and sugarcane bagasse combustion in the bioethanol production process. Technical, economic, and environmental performance of the implementation of CO₂ valorization to produce DMC and SB was assessed. The results for both study cases show that the obtaining of DMC by the direct synthesis of CO₂ and methanol is the most suitable option to be implemented since this product has a high economic value, low capital investment, and high rate of return. As conclusions, post-combustion capture is the most straightforward technology for application in industrial plants. Besides that, the utilization of CO₂ in integrated processes allows the mitigation of greenhouse gases emissions and contributes to an energetically viable production of high value-added products.

Phosphorus causes nutrient pollution in lentic water systems, which act as a reservoir of phosphorus since it is stored within the sediments of these waterbodies. The effects of phosphorus pollution include harmful algal bloom events, hypoxia of waterbodies, and impairment of drinking water sources. Therefore, phosphorus removal or recovery systems must be deployed at point source releases like wastewater treatment plant (WWTP) effluents to mitigate these harmful effects. The economies of scale significantly impact the costs of phosphorus removal, resulting in considerably higher costs in areas where the predominant population structure are small and dispersed towns. Additionally, these areas’ average per capita income is generally lower than significant cities and their metropolitan areas. Therefore, the economic impact of requiring phosphorus removal systems to meet water quality criteria in local communities is crucial information to be considered in designing adequate incentive policies for supporting such water pollution control and prevention efforts. In this work, we assess the costs of preventing and controlling phosphorus releases from WWTP effluents in local communities, accounting for the economies of scale and income distribution throughout the contiguous United States by considering open data sources. The fraction of the average annual income the users would need to allocate to cover the cost of phosphorus removal in the absence of potential governmental incentives ranges from 0.002% to 2.5%. In terms of annual costs per household, the cost of phosphorus removal is strongly influenced by the economies of scale, ranging from 10$/year for the more populated counties favored by the economies of scale to thousands of dollars for those WWTPs serving less populated areas. The results obtained constitute a valuable source of information for designing fair policies that promote an equitable contribution of each community to the control and prevention of nutrient pollution.