The leading-role in food production: phosphorus rocks

Source: http://www.kuglercompany.com/crop-care/fertilizer-application

It is undeniable that phosphorus is vital for life – literally. It is an essential nutrient for all living forms since it plays an important role in DNA/RNA molecules, and is also related to cellular energy transport via ATP (i.e. the P in ATP – the molecule that carries energy around cells) [1]. Phosphorus is not found free in nature, due to its reactivity to air and many other oxygen-containing substances, but it is widely available in different minerals. Phosphorus rocks are a non-renewable resource originated from igneous rocks and marine sedimentary deposits. The widely used approach to obtain these rocks which contain a high content of phosphorus is by mining [2, 3].

Phosphorus rocks are used worldwide for many industrial applications such as detergents, food and drinks, metallurgy. However, the most important use of phosphorus rocks is for the production of phosphate fertilizers [4]. Agriculture is by large the main user of phosphorus globally, accounting for between 80-90% of the total world demand [5]. Phosphorus is one of the three macro-nutrients needed by plants to develop and grow. Together with nitrogen (N) and potassium (K) nutrients, phosphate (P) plays a leading-role in NPK fertilizers which are essential for optimal growth of crops [6]. Unfortunately, a shortfall of phosphorus in soils will result in a reduction of crop yield and can affect food production worldwide.

Phosphorus rocks reserves are being mined at growing rates due to increasing demand. According to the United Nations Food and Agriculture Organisation (FAO), the world demand for fertilisers was estimated to increase around 3 million tonnes every year [7]. The potential threat of phosphorus global limitation has been discussed since the quality of the existing rocks is declining, making the extraction more expensive. Indeed, in 2014, the European Commission declared phosphorus rock as one of the 20 critical resources from the European Union [8]. Estimation of the remaining time phosphate reserves will last are variable and contested, ranging between 100 to 600 years at current production rates [9]. Some researchers have applied Hubbert’s concept of “peak oil” to phosphorus rock mining and named as “peak phosphorus” [10, 11]. Peak phosphorus refers to the moment when production of phosphorus from mining reaches a maximum (its peak); followed by the decrease in quality of the remaining reserves, making it harder to access. Then, mining and processing will be more expensive, which will result in the supply decline and rapidly increase of the prices [5]. Additionally, phosphorus rocks reserves come from a limited number of countries, with large parts of the world, including Europe, being almost totally dependent on imports. As shown in Figure 1, Morocco holds the vast majority of global supplies of this resource, approximately 73%. China is currently in second place with only 4% [10]. This is geopolitically sensitive as Morocco currently occupies Western Sahara and controls its phosphate rock reserves, which could present significant food security risks.

Figure 1: Estimated global phosphorus reserve distribution (USGS, 2017).
Source: https://hess.copernicus.org/articles/22/5781/2018/#&gid=1&pid=1

In order to ensure phosphorus remains available for food production to future generations, the development of novel phosphorus recovery and reutilization initiatives through more sustainable wastewater systems is needed. In particular, human waste from households contributes largely to the amount of nutrients found in waste streams. Approximately, ~50% of the phosphate mass load in municipal wastewater treatment plants comes from human urine. Therefore, urine could play the new leading-role in food production worldwide and help current global demand for phosphorus. Thus, a new perspective that re-evaluates human urine as a reusable and eco-friendly resource should be established. Phosphorus recovery from human urine represents a new promising avenue, since the recaptured phosphorus from waste streams can be utilized for fertilizer production. Additionally, the development of new wastewater systems can offer a sustainable form of sanitation for 2.5 billion people in developing countries that still have no access to proper sanitation [12]. From the extraction and reuse of phosphate from wastewaters, it promotes a circular and sustainable closed-loop of nutrients. And, at the same time, it could increase phosphate availability for fertilizer production worldwide.

References

[1] Oelkers, E. H., & Valsami-Jones, E. (2008). Phosphate mineral reactivity and global sustainability. Elements, 4(2), 83-87. 79.

[2] Hosni, K., & Srasra, E. (2010). Evaluation of phosphate removal from water by calcined-LDH synthesized from the dolomite. Colloid Journal, 72(3), 423–431. 80.

[3] Phosphate rock, 2021. https://mineralseducationcoalition.org/minerals-database/phosphate-rock/ (accessed 30/06/21).

[4] Cordell, D., Drangert, J. O., & White, S. (2009). The story of phosphorus: Global food security and food for thought. Global Environmental Change, 19(2), 292–305.

[5] Tirado, R., & Allsopp, M. (2012). Phosphorus in agriculture: problems and solutions. Greenpeace Research Laboratories Technical Report (Review), 2.

[6] NPK: What is it and why is it so important?, 2021.  https://www.agrocares.com/2020/11/02/npk-what-is-it-and-why-is-it-so-important/ (accessed 30/06/21).

[7] FAO, 2017. World Fertilizer Trends and Outlook to 2020. Food and Agriculture Organization of the United Nations (FAO), p. 66. http://www.fao.org/3/a-i6895e.pdf (accessed 30/06/21)

[8] European Commission (2014). Press Release: 20 Critical Raw Materials – Major Challenge for EU Industry. http://europa.eu/rapid/press-release_IP-14-599_en.htm (accessed 30/06/21)

[9] Van Kauwenbergh, S. J (2010). World Phosphate Rock Reserves and Resources. Technical Bulletin IFDC-T-75.

[10] Cordell, D., & White, S. (2013). Sustainable phosphorus measures: strategies and technologies for achieving phosphorus security. Agronomy, 3(1), 86-116.

[11] Ashley, K., Cordell, D., & Mavinic, D. (2011). A brief history of phosphorus: from the philosopher’s stone to nutrient recovery and reuse. Chemosphere, 84(6), 737-746.

[12] Rollinson, A. N., Jones, J., Dupont, V., & Twigg, M. V. (2011). Urea as a hydrogen carrier: A perspective on its potential for safe, sustainable and long-term energy supply. Energy and Environmental Science, 4(4), 1216–1224.

Towards Smart and Resilient Cities

T

he World’s inhabitants moving from rural areas to cities are in continuous increase. Cities with high inefficient transportation systems and poorly designed buildings, and with high consumption of quantities of fossil fuels and high levels of greenhouse gases emission, are headed to an inevitable collapse. In response, smart cities can replace today’s carbon-consuming urbanism with a new sustainable one. Thanks to the integration of information and communication technology (ICT) and various physical devices connected to the IoT (Internet of things) network, transportation systems, and buildings can be developed towards greater sustainability and resilience [1].

Smart cities aim to improve efficiency, equity, and quality of life by using collected data from different types of electronic methods and sensor with the purpose of improving and optimizing the operations and the management across the city, such as traffic congestion, energy usage, water supply networks, waste, and air quality. In the smart city concept, the community interacts directly with the city infrastructures and services, giving a contribution to the data collected and develop a real-time response which also prepares the city to respond quickly to challenges. Thanks to the use of ICT, the empowerment of citizens is largely emphasized to create a widespread sense of social cohesion, awareness of the relevant issues, and active support of the citizens.

Climate change, water scarcity, and growing waste are three of the main environmental issues challenging in contemporary cities. The resilient city concept aims to increase the quality of life by absorbing and adapting any heterogeneous stress factor and guaranteeing citizens’ safety. Consequently, the integration of the two concepts, as shown in Figure 1, improves simultaneously and synergically the whole city concept. Mitigation strategies combined with adaptation strategies are key to counterbalance possible catastrophic impacts and to absorb the effects of hazards through adaptation and transformation.

Figure 1. Smart and resilient city value chain [2].

To achieve the goals of smart and resilient cities, electrical infrastructures, called smart grid, have a key role in the energy transition. Important objectives of smart grids are the implementation of renewable energy technologies to power entire urban areas, achieving net-zero carbon dioxide emissions, decentralizing power, water, and waste in small-scale systems, endorsing green infrastructure, moving from liner to circular systems, increasing communication among cities and regions in a bidirectional way, and finally achieving “electrification” which refers to transportation supplemented by electric vehicles. Figure 2 shows the expected structural changes from a traditional to a smart system in energy management, made possible by the increased use of digital tools.

Figure 2. Characteristics of a traditional system versus a smart system [3].

To promote the smart and resilient concept, the European Commission has launched the European Innovation Partnership for Smart Cities and Communities (EIP-SCC), with the aim to support the energy production, distribution, transportation, and digital technologies and to improve services while reducing energy, as well as greenhouse gas emissions and resource waste [4,5].

In smart cities, circular economy is a key concept. Our global consumption is exceeding the capacity of the planet to regenerate, and because of this, it is important to shift from a linear to a closed-loop system. The main idea is to minimise the use of resource inputs and the creation of waste by reusing, repairing, and recycling. Waste materials and energy are input for other processes. The circular model has to be employed in every industrial sector, in the economic, social, and environmental production and consumption. An example of the circular economy application is the recovery of nutrients and the production of bioplastics from daily processed wastewater streams. Also, the scarcity of water is already a serious problem and many territories have been affected by water shortages, which are destined to worsen as a result of climate change [6]. Therefore, the need to encourage the use of alternative sources of water and the reuse of wastewater. Furthermore, the need to focus on the sustainable use of natural resources, the fostering of environmental remediation, the improvement and enhancement of ecosystems, the management and protection of water and air quality, the monitoring of the response to environmental threats for human health.

In the face of climate change, it is important to develop solutions, technologies, and financial response to possible impacts. A key asset of smart and resilient cities is the dynamic interplay of learning capacity, persistence, adaptability, and transformability across multiple scales, as shown in Figure 3 [7,8]. The model is structured as a cyclical process characterized by three different stages connected through a feedback loop: strategies’ definition, implementation, and management. Along the process, there are different periods: short, medium, and long term. In the short term, strategies are orientated to improve cities’ capacities to climate-related impacts by increasing systems’ persistence. In the medium term, cities enhance their capacity to deal with unexpected impacts by improving systems’ adaptability. In the long term, strategies should drive the urban transition towards the prevention of future climate-related impacts by improving cities’ transformability.

Figure 3. The conceptual model for building up smart and resilient cities in the face of climate-related challenges [9].

The capacity of continuous and dynamic learning is crucial for the smart and resilient city concept. Learning capacity can be improved using several approaches such as networking, the ability to connect people and devices for exchanging data and information, monitoring, to detect conditions of urban system, knowledge, to elaborate the information, memory, to learn from past events and predict possible future scenarios, and collaboration and participation, to involve people in the decision-making process [9].

To conclude, it is important to move towards smart and resilient cities for both our safety and the one of our Planet. The aim is to live in a city capable to optimize and interconnect the components that characterize the urban systems by taking advantages of the modern technologies and the big data available. A creative city able to reinvent a new equilibrium against destabilizing external stresses and to adapt to new circumstances.

References:

[1]        R. Chapman, Resilient Cities: Responding to Peak Oil and Climate Change, Journal of Urban Design. 17 (2012) 301–303. https://doi.org/10.1080/13574809.2012.666179.

[2]        A. Visvizi, C. Mazzucelli, M. Lytras, Towards an ICTs’ enabled integrated framework for resilient urban systems, Journal of Science and Technology Policy Management. 8 (2017) 227–242. https://doi.org/10.1108/JSTPM-05-2017-0020.

[3]        Bartz/Stockmar, Smart Grid – Staying big or getting smaller, (2018). https://commons.wikimedia.org/wiki/File:Staying_big_or_getting_smaller.jpg (accessed April 2, 2021).

[4]        European Commission, Energy and smart cities, (2020). https://ec.europa.eu/energy/topics/technology-and-innovation/energy-and-smart-cities_en?redir=1 (accessed April 2, 2021).

[5]        European Commission, Analysing the potential for wide scale roll out of integrated Smart Cities and Communities solutions, (2016). https://smart-cities-marketplace.ec.europa.eu/sites/default/files/SCC Solution 80 Best Practice Examples.pdf (accessed April 5, 2021).

[6]        ENEA, Circular management of water resources, (2021). https://www.fondazionesvilupposostenibile.org/gruppo-di-lavoro-per-la-gestione-circolare-delle-risorse-idriche/ (accessed April 3, 2021).

[7]        C. Folke, S.R. Carpenter, B. Walker, M. Scheffer, T. Chapin, J. Rockström, Resilience thinking: Integrating resilience, adaptability and transformability, Ecology and Society. 15 (2010). https://doi.org/10.5751/ES-03610-150420.

[8]        S. Davoudi, E. Brooks, A. Mehmood, Evolutionary Resilience and Strategies for Climate Adaptation, Planning Practice and Research. 28 (2013) 307–322. https://doi.org/10.1080/02697459.2013.787695.

[9]        R. Papa, A. Galderisi, M.C.. Vigo Majello, E. Saretta, Smart and Resilient Cities. A Systemic Approach for Developing cross-sectoral strategies in the face of climate change, TeMA Journal of Land Use, Mobility and Environment. 1 (2015) 1–49. https://doi.org/10.6092/1970-9870/2883.