Hydrogen economy


he global energy demand is expected to grow significatively in the next decades, driven by economic and population growth.1However, our current energy sector is heavily reliant on fossil-base energy carriers, such as coal, oil and natural gas.

The indiscriminate use of these resources, with consequent emission of green house gases (GHG), is the primary cause for the alarming increase in world’s temperature. In 2021, energy-related carbon dioxide (CO2 – one of the main GHG) emissions reached 36.3 billion tons (6% of the total CO2 emissions), setting a new record, the highest ever.2

In response to this threat of climate change, the Paris Agreement set the goal of limiting the global warming to 2 degrees above the pre-industrial level. A key player in this energy transition is green hydrogen. In fact, a renewed interest in hydrogen, already under the radar as potential alternative energy carrier many years, has surged in the last five years to meet the Paris Agreement. The production of green hydrogen from water electrolysis might also represent a more accessible energy carrier, contrary to a fossil-fuel-based society where inequal distribution of resources and geopolitical instability repeatedly threaten the worldwide stability of the current energy system.

As such, the European Union (EU) has recently set ambitious goals for the next decades aiming to increase the current yearly hydrogen production of about 100 MW, to 40 GW ( ̴ 10 million tons) in 2030.3

Green hydrogen production technologies are currently available at different level of maturity. Alkaline electrolysers (TRL – technology readiness level – 9) and polymer electrolyte membrane electrolysers (TRL 8), and  represent the most promising technology to be used on a large scale in the coming years.4 Other promising technologies are solid oxide electrolysis (TRL 6), natural gas reforming with CO2 capture (TRL 8), biomethane reforming with CO2 capture (TRL 8), low temperature biomass gasification (TRL 7) and high temperature biomass gasification (TRL 6).4 The reported costs for these technologies are presented in Figure 1. Other alternative hydrogen production technologies are also being developed.5,6

Figure 1. Reported costs ranges for upcoming hydrogen production technologies.4

Even we have several technologies which we could be using nowadays as seen in Figure 1, the technological cost needs and related challenges prevent its implementation. For example, the use of alkaline and polymer electrolysis is challenged by the availability of low carbon electricity and as well as its high costs while the implementation of natural gas or biomethane reforming with CO2 capture is challenged by the fugitive methane emissions from the natural gas supply, and the availability of a CO2 transport and storage infrastructure.7,8

Hydrogen has been for long time considered as a promising future green energy carrier, but technological and socio-economical barriers did not allow the H2 economy to be deployed at large scale. Will the next decades be finally the years in which we will witness a full take off of green hydrogen technologies supporting the transition towards a carbon neutral energy system?

We really hope so…

Recent news of interest:

  • European Commission’s Clean Hydrogen Partnership (CHP) has launched a call of proposals offering €300.5m of grants “to support projects that boost renewable hydrogen production, reduce its costs, develop its storage and distribution solutions, and stimulate the use of low carbon hydrogen in hard to abate sectors, such as energy intensive industries, aviation or heavy duty transport”.: Source: https://www.clean-hydrogen.europa.eu/apply-funding/call-proposals-2022/call-proposals-2022_en

  • In the Netherlands, the growth fund programe GroenvermogenNL announced that they will receive extra €500m adding to the existing €338m to: “accelerate the production and use of green hydrogen and related technology in various industrial chains, such as chemistry, kerosene, steel or fertilizer”. Source: https://www.groenvermogennl.org/en/news/500-miljoen-extra-voor-groene-waterstof-en-chemie-via-groenvermogennl


1. IRENA, Global Energy Transformation: A roadmap to 2050, International Renewable Energy Agency, 2018, Abu Dhabi.

2. International Energu Agency (IEA) 2021: “https://www.iea.org/news/global-co2-emissions-rebounded-to-their-highest-level-in-history-in-2021”

3.European-Commission, A hydrogen strategy for a climate-neutral Europe. COM(2020) 2020, 301 final.

4.Van der Spek, M.;  Banet, C.;  Bauer, C.;  Gabrielli, P.;  Goldthorpe, W.;  Mazzotti, M.;  Munkejord, S. T.;  Røkke, N. A.;  Shah, N.;  Sunny, N.;  Sutter, D.;  Trusler, J. M.; Gazzani, M., Perspective on the hydrogen economy as a pathway to reach net-zero CO2 emissions in Europe. Energy & Environmental Science 2022, 15 (3), 1034-1077.

5.Rioja-Cabanillas, A.;  Valdesueiro, D.;  Fernández-Ibáñez, P.; Byrne, J. A., Hydrogen from wastewater by photocatalytic and photoelectrochemical treatment. Journal of Physics: Energy 2020, 3 (1), 012006.

6.Sazali, N., Emerging technologies by hydrogen: A review. International Journal of Hydrogen Energy 2020, 45 (38), 18753-18771.

7.Parkinson, B.;  Balcombe, P.;  Speirs, J. F.;  Hawkes, A. D.; Hellgardt, K., Levelized cost of CO2 mitigation from hydrogen production routes. Energy & Environmental Science 2019, 12 (1), 19-40.

8. Lane, J., Greig, C. & Garnett, A. Uncertain storage prospects create a conundrum for carbon capture and storage ambitions. Nat. Clim. Chang. 2021 11, 925–936.

The REWATERGY experience (part 2)

Raffaella Pizzichetti


first moved out from my comfort zone at the age of 16, when I dipped myself in an exciting and strong experience of 10 months abroad, in the USA, very far from home. I grew up enormously in this adventure. I met amazing people that will always occupy an important place in my heart, no matter the distance. I learned to live in a completely different environment, with different habits and traditions, and communicate in a language that was unknown to me at the beginning. My second journey started right after high school, at the age of 18, when I moved to Turin for my studies. This time the emotions were even more intense. I was moving away from home for an unknown time, and I was starting a new chapter of my life with no pillars supporting me, far from family and friends. It was my new challenge. Starting from zero in an estranged house with unknown people, but soon I was already surrounded by new friends and joyful events. There were tough moments, of course, but the juice was worth the squeeze. A new adventure started when I won the scholarship for the Double Degree Master Programme between the Polytechnic of Turin and the Royal Institute of Technology in Stockholm in Chemical and Sustainable Processes Engineering.

This time new challenges to face, a third language to learn, another culture to embrace, and intense weather conditions to live in. Nevertheless, it was another amazing experience. The broad international environment around me was the key to my personal and educational growth. It made me more creative and open-minded and helped my promptness and flexibility. As this last journey was coming to an end, I was not ready to go back home yet. I was curious and ready to explore a bit more of the world, keep learning from the other cultures and exciting environments. REWATERGY offered me this opportunity, full of training events and secondments around Europe with 36 months equally split into two different countries. Other than this, the project offered me the opportunity to gain experience in both academia and industry, enhancing my career prospects through the PhD on the very topic I am passionate about, the water-energy nexus, addressing climate change challenges and embracing a circular economy concept. Soon, I found myself packing again and getting ready for Madrid, my first destination. I started the project in a very cheerful atmosphere in the GIQA group at Rey Juan Carlos University. Then, I had the chance to meet the rest of the consortium in our first meeting in Cambridge and get to know better the other ESRs in our first training in Belfast. Unfortunately, the COVID-19 pandemic changed many aspects of the project and created new challenges – different and, in some respects, more difficult than those already expected. My time in Madrid concluded successfully, with highs and lows, and about 6 months ago I moved to my second destination, Cork. Starting new in another city, in another country, in this “different world” with social restrictions, has been tough. However, thanks to supportive friends and colleagues, I am making my way through the worst moments and enjoying all the good that this project is offering me.

Adriana Rioja


he first half of the REWATERGY programme is over. It was almost 2 years ago, when I decided to leave my job as Battery Engineer in Netherlands and join REWATERGY programme. This programme presented me with the opportunity of doing a doctorate while still being in contact with industry, as well as pursuing my interest in electrochemical research applied to energy and sustainability. It has been 18 months of fast-growing experiences, which I think have really contributed to both personal and professional development. My first placement of the REWATERGY programme was at Ulster University in Belfast. Even though I had already been in Northern Ireland doing an exchange at high school, the only thing I could remember from that time was how much it rained and that I barely could understand any English with Northern Irish accent. Therefore, I prepared myself mentally for a lot of rain and to not understand much of the English. Fortunately, my understanding of the accent greatly improved, but it still took me some weeks to clearly understand some of my colleagues and supervisor. From my first days in Belfast, I felt the hospitality and kindness of the people around me, which contributed to making me feel welcome and have very nice time. After travelling a bit around, it made me remember how beautiful NI is filled with amazing landscapes, beaches, cliffs forests and hills. Moreover, I really enjoyed Belfast’s atmosphere, particularly the nightlife, filled with traditional pubs, where you can enjoy live music. Unfortunately, after six months of my arrival in NI, the whole world was hit by the global pandemic of COVID-19. This impacted, to different extent, both the personal and professional life of many people. For me personally it was also a challenging time, as I saw Belfast quickly transformed into a ghost town. I had to deal with being away from my family, as well as completely changing the way of working, as we had almost no access to the university for 1 full year. Fortunately, I had the luck of sharing these difficult moments with a small group of friends. I hope to have the opportunity to return to Northern Ireland sometime in the future and keep exploring its amazing nature and atmosphere. Most memorable moments from the first part of this experience include: meeting all my colleagues at Ulster University, returning to do experiments in a laboratory, the meeting held in Cambridge where we met everyone involved in REWATERGY, the training courses in Belfast with all the ESR, my friends cooking amazing traditional food from their countries, daytrips exploring NI and evenings listening to live Irish music in the pubs. Now already settled at my second placement at the company Delft-IMP in Netherlands, I am hoping to fill the next months with new memories and experiences which would make me grow further both personally and professionally.

From water purification to gas mask filters: the wide…


ith a total sales of 617 million euros in 2020 worldwide, the BRITA Company produces water jugs, kettles and tap attachments integrated with disposable filters. The filters, which contain activated carbon and ion-exchange resin, have the goal to remove substances that may impair taste, to reduce the carbonate hardness (limescale) as well as copper and lead [1]. This process that is performed daily on drinking water at home, is called adsorption. This phenomenon is a separation process involving the selective transfer of solutes (adsorbates) in a fluid phase to the surface of a solid (adsorbent). Through adsorption, small particles or dissolved contaminants in water can be removed. However, adsorption should not be confused with absorption, in which particles penetrate into another substance, just like a sponge that soaks in liquids. While adsorption describes the enrichment of absorbates onto the surface of an adsorbent, absorption is defined as a transfer of a substance from one bulk phase to another bulk phase [2]. The substance is enriched within the receiving phase and not only on its surface, as it can be seen in Figure 1. The dissolution of gases in liquids is a typical example of absorption.

Figure 1: Schematic representation of: (a) adsorption and (b) absorption processes.

The commonly used material for water treatment through adsorption is activated carbon. This adsorbent is a carbonized and chemically activated material through oxygen treatment, that results in millions of tiny pores between carbon atoms opening up. This highly porous material presents surface area values usually between 500–1500 m2/g and can be used in a powdered or granular form. Due to its active adsorption sites, high surface area, porous structure, surface reactivity, inertness, and thermal stability, this material is a popular choice among adsorbent materials applied industrially [3].

Besides water purification, the adsorption technique has many other applications. Some of them are included in our daily life, such as applying silica or aluminium gels in packaging to remove moisture and control humidity. Others are used industrially, such as the removal of undesirable colouring matter. Adsorbent materials can remove colours from solutions by adsorbing coloured impurities. As shown in Figure 2, Tourmaline, a naturally-occurring borosilicate mineral, was successfully used to remove red dye [4]. Other industrial applications includes the separation of noble gases, where the difference in the degree of adsorption in the adsorbent materials allows to separate a gas mixture; and chromatographic analysis based on selective adsorption to separate a mixture. For example, in column chromatography, a long and wide vertical tube is filled with a suitable adsorbent, and the solution of the mixture is poured from the top and then collected one by one from the bottom [5].

Figure 2: adsorption of diazo dye DR23 onto powdered tourmaline.
Source: https://doi.org/10.1016/j.arabjc.2016.04.010

Another popular use of the adsorption principle is for gas masks. To filter out harmful gases such as methane, chlorine and sulphur dioxide, the gas mask filters are made with adsorbent materials (usually with activated carbon) to purify the air. From the inlet of the gas mask, the air flows through a particulate filter, followed by an adsorbent filter, and then through another particulate filter, which traps charcoal dust, according to Figure 3 [6].

Figure 3: typical disposable filter cartridge for a respirator.
Source: https://science.howstuffworks.com/gas-mask2.htm


[1] BRITA – key facts & figures, 2022. https://www.brita.co.uk/facts-figures (accessed 13/01/2022)

[2] Worch, E. (2021). Adsorption technology in water treatment. de Gruyter.

[3] Soni, R., Bhardwaj, S., & Shukla, D. P. (2020). Various water-treatment technologies for inorganic contaminants: current status and future aspects. In Inorganic Pollutants in Water (pp. 273-295). Elsevier.

[4] Liu, N., Wang, H., Weng, C. H., & Hwang, C. C. (2018). Adsorption characteristics of Direct Red 23 azo dye onto powdered tourmaline. Arabian journal of chemistry, 11(8), 1281-1291.

[5] Application of Adsorption: Definition and Examples, 2022. https://www.embibe.com/exams/application-of-adsorption/ (accessed 13/01/2022)

[6] How Does a Gas Mask Protect Against Chemical Warfare?, 2013. https://www.nationalgeographic.com/science/article/130830-gas-masks-syria-israel-chemical-warfare (accessed 13/01/2022)

A universal right: have access to safe drinking water


n 2015, the United Nations General Assembly set up 17 Sustainable Development Goals (SDG) to “achieve a better and more sustainable future for all” by 2030. The SDGs are globally interlinked and include, among others, the end of poverty in all its forms, reduction of inequalities, climate actions, and a turn into more affordable and sustainable energy. In particular, SDG 6 focuses on ensuring availability and sustainable management of water and sanitation for all. Figure 1 shows the six key targets and the two additional targets for resource mobilisation and policy to be achieved within SDG 6 [1]. Access to safe drinking water and sanitation is essential for the realisation of all human rights and the development of life. However, despite the growing involvement of all countries, there is still a long way to go. In 2020, billions of people still lacked access to safe drinking water, sanitation, and hygiene [2].

Figure 1. Key targets for SDG 6, modified from [1].

Water and sanitation are at the core of sustainable development since they would help at the same time poverty reduction, economic growth, and environmental sustainability [3]. Nevertheless, overexploitation, pollution, and climate change have led to severe water stress in places across the world, worsening the situation with increasing disasters such as floods and droughts. 80% of wastewater in the world flows back into the ecosystem without being treated or reused, and 70% of the world’s natural wetland extent has been lost due to anthropogenic causes, including a significant loss of freshwater species. The consequences of lack of safe water are lethal: according to the UN’s 2018 annual report on the SDGs, around a thousand children die every day due to diseases related to poor hygiene and quality water [4].

Moreover, COVID-19 pandemic posed an additional impediment in accessing safe water and other sanitation and hygiene services, which on the other hand, were needed to prevent the spreading of the virus [5].

Household water treatments and safe storage (HWTS)

Most of the population without access to safe water is in developing countries where lack infrastructure and financial resources. Providing access through centralised systems would indeed be very challenging. Large distribution systems involve a lot of operation and maintenance, and water can get contaminated during the distribution or handling in the household [6]. Low-cost, easy-to-use and sustainable domestic treatments are needed in these locations. Household-level Water Treatment and Safe Storage (HWTS) is the most cost-effective intervention that vulnerable populations can rapidly implement in developing countries to improve microbial water quality and reduce waterborne diseases [7]. HWTS is a multi-barrier approach with 5 steps that equally contribute to reducing the risk of unsafe water (shown in Figure 2). The multi-barrier approach is the best way to minimise the threats coming from drinking unsafe water. Waterborne pathogens can be eliminated by household water treatment like boiling, chlorination, separation with specific ceramic filters (filtration) or adding chemical coagulants to agglomerate the pathogens, settle them and separate them (flocculation). Relying on more than one technology to improve water quality is key to ensuring high decontamination from protozoa, bacteria, and viruses and reducing the health risks associated with them.

Figure 2. Household water treatment and safe storage multi-barrier approach

Source protection

Actions should be taken to improve the water sources or points of collection. This can include regular cleaning of the area around, moving latrines away or downstream, and building fences to prevent animals from contaminating open water sources.


Gravity settling is the simplest household water treatment and safe storage (HWTS) method. It removes some turbidity and improves the visual appearance, although it is limited in pathogen removal and can be affected by secondary contamination. Coagulation enhances settling making the particles stick to each other. However, coagulation is affected by several factors such as temperature, pH, and coagulant dose. Sedimentation alone is not a complete treatment but allows subsequent treatment steps to be more effective.


Membrane filtration is a rapidly growing field in water treatment. There are different kinds of membranes based on size exclusion mechanism, electrostatic effect and biological activity. The main configurations include dead-end, cross-flow, flat sheet, and hollow fibres, and they provide a good barrier to particles, protozoa, bacteria, and viruses. It has a simple operation without affecting the taste and reduces turbidity. However, the main drawback is the membrane fouling, which results from particle retention, and increases the operating pressure. Fouling can be reversible or irreversible but can be limited by regular backwashing and periodic cleaning. Also, filtration does not protect against recontamination.

Ceramic filtration consists of ceramic pot filters and candle filters. It has a simple operation and can be produced locally without electricity. It is also socially accepted and highly used in developing countries. However, it has moderate effectiveness, variable water quality, and no residual protection.

Biological filtration mainly includes biosand or slow sand filtration. The biological layer takes time to develop, but it does not need backwashing, although other cleanings may be needed. It’s possible a long-term use, but there is a high risk of recontamination.


Heat is the oldest HWTS, and it is widely accepted, understood, and promoted. Boiling water is effective against all viruses, bacteria, and protozoa, and turbidity is not a problem. However, it takes a long time if we include cooling, and there is a high possibility of recontamination.

Ultraviolet radiation is effective with most bacteria, protozoa, and viruses and can be artificial or natural. The dose is calculated as intensity*time, and typical doses consist of 400 J/m2. UV-C lamps can act directly on the DNA while using natural sunlight through the Solar Disinfection process (SODIS) we can exploit the UV-A and UV-B spectra of the sun. SODIS consists of exposing PET bottles for 6 hours in good weather conditions. UV treatment is highly effective and, in the case of SODIS, is also simple and inexpensive. However, it takes time and depends on turbidity. Furthermore, when using sunlight is highly dependent on climate conditions.

Chlorine is a chemical disinfection and the second most reported HWTS. Chlorine is a strong oxidant and acts on the cell wall, DNA, and enzymes. It is highly effective, other than simple to use and low cost. Furthermore, it gives residual protection when the water is stored. The main drawbacks are the change in the taste and odour, the ineffectiveness against protozoa at small concentrations, and the formation of by-products.

Safe Storage

Even if household drinking water is treated, it may still become re-contaminated through storage in dirty or uncovered containers or through contact with dirty hands and utensils. Appropriate containers are designed to minimise recontamination. Hygienic location is also important as environmental contamination can easily affect the final water quality. The containers should have a lid or be narrow-necked to limit recontamination.

ESCAPE ROOM: Save the population from water scarcity

In the following link you have access to my escape room about water treatment. Learn more about it, challenge yourself to solve the riddles, and find the key to saving the population from water scarcity.

https://docs.google.com/presentation/d/1Bc6ZaYtM_e_o8kQ3DOKal53YA2nkU0IUqI_kIAJQbG4/preview#slide=id.gf90f95fc23_0_2 (in English)

https://docs.google.com/presentation/d/1a88X7-rcjRJbMdSVzlThhoMJRbf0NeIudHxO3d2cMVo/preview#slide=id.gf90f95fc23_0_2 (in Spanish)


[1]        Goal 6: Clean Water and Sanitation. Available at: https://www.globalgoals.org/6-clean-water-and-sanitation (accessed December 12, 2021).

[2]        Goal 6: Department of Economic and Social Affairs. Available at: https://sdgs.un.org/goals/goal6 (accessed December 16, 2021).

[3]        Water and Sanitation: Department of Economic and Social Affairs. Available at: https://sdgs.un.org/topics/water-and-sanitation (accessed December 14, 2021).

[4]        UN Environment 2018 Annual Report – UN Environment Programme. Available at: https://www.unep.org/resources/un-environment-2018-annual-report (accessed December 16, 2021).

[5]        UN Environment 2021 Annual Report – UN Environment Programme. Available at: https://www.un.org/annualreport/index.html (accessed December 12, 2021).

[6]        Household Water Treatment and Safe Storage (HWTS). SSWM – Find tools for sustainable sanitation and water management! Available at: https://sswm.info/sswm-solutions-bop-markets/affordable-wash-services-and-products/affordable-water-supply/household-water-treatment-and-safe-storage-%28hwts%29 (accessed December 16, 2021).

[7]        The International Network to Promote Household Water Treatment and Safe Storage. Available at: https://www.who.int/household_water/advocacy/combating_disease.pdf (accessed December 13, 2021).

The danger of climate change


limate change (CC), which are changes that occur in the global atmosphere, shows a clear variation in either the state of the climate or its fluctuations. The CC that occurs on Earth usually continues for long periods of decades or more. CCs have begun since the formation of the earth, as the earth has gone through many climatic changes such as ice ages and heat waves that have taken over the earth for millions of years, as ice caps and forests spread, and sea levels rose and decreased, and all of this is mainly due to climatic changes. It is worth noting that it must differentiate between climatic changes and weather diversity, as climatic changes last for very long periods, while weather changes last for relatively short periods 1,2.

CC has a serious effect on the environment include effects on Global warming, crops, water resources, the strength of hurricanes, increasing drought, and human health. CC is one of the most important reasons that affect the environment, as droughts and changing global rainfall patterns can destroy livelihoods. In addition to the spread of dangerous diseases such as malaria and dengue fever. It is worth noting that climatic changes affect the natural wild habitats. As well as it creates crises that are difficult to recover from 3.

CC contribute to the increase in the average temperature of the Earth’s surface by more than 0.9 degrees Celsius since 1906. Human activities are the basis of increasing Global warming, which contributes to the addition of greenhouse gas to the atmosphere leading to a rise in the global temperature. This rise led to melting of glaciers and sea ice, change in rainfall patterns, rising Sea levels, destruction of some wild habitats, and migration of animals to cooler regions 4.

CCs such as changes in temperature, weather intensity, and the proportion of carbon dioxide in the atmosphere affect agricultural crops significantly, as these changes can affect the increase or decrease in the number of crops planted according to the type grown and the conditions required for them to grow. The most important effects of CC on crops involve the increase in the level of carbon dioxide, which is good for crops, as it can help increase the growth of plants. However, Extreme temperatures and increased rainfall inhibit crop growth. Also, both floods and droughts prevent the growth of crops. Also, CCs can encourage the growth of weeds, fungi, and pests, which will prevent the growth of crops 5.

 Further, CC greatly affects water supplies and food production in various parts of the world, and as a result, the lack of drinking water can lead to very great damage to all different sectors. The most prominent effect of CC on water resources includes increased water evaporation, which affects the absorption of water from oceans, lakes, soil, and plants. Heavy rainfall on the land leads to floods, which can cause the death of large numbers of people and animals. Also, the temperature change leads to a change in the main ocean currents 6.

CC is a key factor in increasing drought on Earth, as rising temperatures can accelerate the transfer of water from the Earth’s surface to the atmosphere, which will increase drought, and thus drought can cause great damage to water resources in the future. It can also affect population growth, increase pollution, raise living standards, change eating habits, change agricultural practices, increase industrial activities, change economic activities, increase demand for water and energy, and changes land use and urbanization 7.

Additionally, CC affects in some way on hurricanes. The stronger the hurricanes, the greater the destruction caused by them. As it is believed that hurricanes appear as a result of a state of instability in the atmosphere, and thunderstorms resulting from CC may be the main reason for the emergence of Hurricanes 8.

In addition to the impact of CC on the environment, it also affects human health significantly, as a change in climate can change the basic factors that affect human health, as CC can result in air pollution, availability and quality of food and drinking water. Therefore, the safety of these factors is important to maintain human health. Researchers at the World Health Organization expect that CC will contribute to an increase in deaths by 250,000 annually between 2030 and 2050. The most prominent effects of CC on human health includes the effects on the spread of insects that carry infectious diseases, increasing human fears causing anxiety and despair, the increase in temperature which affects the action of some types of medications, such as those used to treat schizophrenia. Also, human exposure to high temperatures leads to many health problems such as Heatstroke, heat exhaustion, muscle spasms, and respiratory diseases.

Also, CC causes an increase the migration from drought-ridden rural areas to urban cities, where these migrations will overcrowd urban cities, and thus raise the risk of disease. There are a set of studies and statistics that have been recorded for cases that have suffered from the effects of CC, which have led to major health problems in humans and even reached death. According to the Centers for Disease Control and Prevention, suicide rates increase with higher temperatures, the nutritional value of foods can decrease due to CC, and about 98 people die each year due to floods in the United States. Researchers say that natural disasters greatly affect people’s mental health, and these disasters can also cause post-traumatic stress disorder (PTSD) 9,10.

Therefore, several actions must be taken by individuals and governments to reduce the effect of CC. These actions involve Increasing energy efficiency and using renewable energy, applying climate-smart farming practices and forest expansion, reducing the use of fossil fuel, and reducing the use of plastic, which is highly contribute to the generation of greenhouse gases.


  1. “What is Climate?” WMO, www.wmo.int,
  2. Climate Change”, Encyclopedia, https://www.encyclopedia.com/earth-and-environment/atmosphere-and-weather/weather-and-climate-terms-and-concepts/climate-change
  3. Environment and climate change”, UNICEF, https://www.unicef.org/environment-and-climate-change
  4. Effects of global warming”, National Geographic, https://www.nationalgeographic.com/environment/article/global-warming-effects
  5. Climate Change Impacts”, EPA, https://19january2017snapshot.epa.gov/climate-impacts/climate-impacts-agriculture-and-food-supply_.html
  6. How Climate Change Impacts Our Water”, Columbia, https://news.climate.columbia.edu/2019/09/23/climate-change-impacts-water/
  7.  “Climate Change and Its Impact on Water Resources”, Researchgate, https://www.researchgate.net/publication/314210788_Climate_Change_and_Its_Impact_on_Water_Resources
  8. Tornadoes and Climate Change”, National Geographic, https://www.nationalgeographic.org/article/tornadoes-and-climate-change/#:~:text=Some%20studies%20predict%20that%20climate,of%20supercell%20thunderstorms%20produce%20tornadoes
  9. “Climate change and health: Impacts and risks”, Medical News Today, https://www.medicalnewstoday.com/articles/climate-change-and-health#food-security
  10. At the Crossroads of Climate Change and Global Security”, UN, https://www.un.org/en/chronicle/article/crossroads-climate-change-and-global-security

Towards energy self-sufficiency: biogas production in wastewater treatment plants


ater is a vital resource in our society, not only for human consumption but for any kind of activity (food production, industrial processes…). During human activity, we contaminate water streams, so, before they can be returned to water bodies, such as lakes or rivers, they must be decontaminated. There is where wastewater treatment plants (WWTP) come into play. WWTP are the facilities where all the wastewater that we produce is treated to remove organic matter, solids and nutrients before it is returned to the environment [1]. During their operation , WWTP become important energy consumers. In the U.S., wastewater treatment accounts for 3 – 4% of national electrical demand, being the electric power consumption the highest operation cost in these plants (more than 30%) [2].

During their operation, WWTP generate a big volume of sewage sludge, around 250 grams of dry solids per m3 of treated wastewater. Sewage sludge is produced during the primary and secondary settling (Figure 1) and it is mainly composed of the organic matter and solids removed from wastewater, being usually rich in nutrients [3]. Furthermore, sewage sludge cannot be directly disposed, but it requires prior treatment and its management accounts for 30% of WWTP operating costs [2]. Therefore, it is crucial to apply strategies that enables a sustainable management of the sludge, allowing to get the most of it.

Figure 1. Schematic of a wastewater treatement plant with biogas production by anaerobic digestion of sewage sludge.

Anaerobic digestion is a widespread technology that allows generation of renewable energy in the form of biogas during sewage sludge treatment. During this process, microorganisms break down the organic matter present in the sludge into smaller molecules, producing biogas. Biogas is formed by a mixture of mainly methane and carbon dioxide and it can be used as a fuel for heat and electricity generation [3].

However, sewage sludge cannot be directly used from primary and secondary settling for anaerobic digestion. The generated sludge goes through a series of process in the WWTP (Figure 2) [3]. First, the sludge is sieved and thickened to reduce the content of water and hence the energy consumed during its digestion. The thickened sludge is then pumped into the digesters and continuously stirred in anaerobic conditions at mesophilic temperatures (35 – 42 °C) during a retention time of around 20 days. About a third part of the solid matter from the sludge is transformed into biogas during digestion, so the digested sludge becomes again very liquid and needs to be dewatered before its final disposal. Dewatering of the sludge is normally achieved by mechanical pressure or centrifugation, although sometimes it can be heat dried to remove even more water. The dewatered sludge can then be used for agriculture, disposed in a landfill or sent to an incineration plant [3]. Finally, as a result of the dewatering process, a liquid stream with a high concentration of contaminants is produced and recirculated to the entrance of the WWTP [4].

Figure 2. Sewage sludge treatment processes in a wastewater treatment plant with biogas production by anaerobic digestion [3].

During the anaerobic digestion, biogas is produced by biological breakdown of the biomass. Typical composition of biogas from sewage sludge consists of 60 – 67% methane, 33 – 40% carbon dioxide and traces of other compounds such as hydrogen, nitrogen, siloxanes and hydrogen sulphide [5]. Due to its high methane content, this biogas is a source of energy that is commonly used in WWTP to cover some of their energy demand. Biogas can be used to produce heat directly in a boiler, just as we all do at home. However, the most common application for the biogas produced in wastewater treatment plants is its use in Combined Heat and Power (CHP) units (systems that produce both, electricity and heat, from a single fuel source) [6]. Combustion engines and micro turbines are the most widely used CHP technologies, although some alternatives such as fuel cells are attracting attention due to their higher electrical efficiency [7], [8]. The heat and electricity produced through these CHP units is used in the WWTP to reduce the energy demand. Heat autonomy is generally achieved with the biogas, and the electrical consumption can be reduced from 30 to 70%, depending on the WWTP size [3]. Furthermore, some technologies aim to go even further to maximize the biogas production by co-digestion of other organic wastes from the WWTP itself (such as the grease removed in the pre-treatment) [9] or from other sources (such as food wastes or municipal solid wastes) [10]. Lastly, the biogas produced can be upgraded (i.e. increasing its methane content) so it can be used as a vehicle fuel or even injected to the natural gas grid [2].

Summarising, water and energy are vital and inseparably connected resources. Wastewater treatment processes consume a large amount of energy, which is translated into environmental, social and economic impacts. Anaerobic digestion at WWTP is a technology that produce biogas, a green energy source that can help reducing the footprint of the water cycle and supposes a step-forward towards a more sustainable society.


[1]         J. Palatsi, F. Ripoll, A. Benzal, M. Pijuan, and M. S. Romero-güiza, “Enhancement of biological nutrient removal process with advanced process control tools in full-scale wastewater treatment plant,” Water Res., vol. 200, p. 117212, 2021, doi: 10.1016/j.watres.2021.117212.

[2]         Y. Shen, J. L. Linville, M. Urgun-Demirtas, M. M. Mintz, and S. W. Snyder, “An overview of biogas production and utilization at full-scale wastewater treatment plants (WWTPs) in the United States: Challenges and opportunities towards energy-neutral WWTPs,” Renew. Sustain. Energy Rev., vol. 50, pp. 346–362, 2015, doi: 10.1016/j.rser.2015.04.129.

[3]         N. Bachmann, J. la C. Jansen, D. Baxter, G. Bochmann, and N. Montpart, “Sustainable biogas production in municipal wastewater treatment plants,” IEA Bioenergy, 2015.

[4]         A. Thornton, P. Pearce, and S. A. Parsons, “Ammonium removal from digested sludge liquors using ion exchange,” Water Res., vol. 41, no. 2, pp. 433–439, 2007, doi: 10.1016/j.watres.2006.10.021.

[5]         A. Kiselev, E. Magaril, R. Magaril, D. Panepinto, M. Ravina, and M. C. Zanetti, “Towards Circular Economy: Evaluation of Sewage Sludge Biogas Solutions,” Resources, vol. 9, no. 91, pp. 1–19, 2019.

[6]         M. MosayebNezhad, A. S. Mehr, M. Gandiglio, A. Lanzini, and M. Santarelli, “Techno-economic assessment of biogas-fed CHP hybrid systems in a real wastewater treatment plant,” Appl. Therm. Eng., vol. 129, pp. 1263–1280, 2018, doi: 10.1016/j.applthermaleng.2017.10.115.

[7]         D. M. Riley, J. Tian, G. Güngör-Demirci, P. Phelan, J. Rene Villalobos, and R. J. Milcarek, “Techno-economic assessment of CHP systems in wastewater treatment plants,” Environ. – MDPI, vol. 7, no. 10, pp. 1–32, 2020, doi: 10.3390/environments7100074.

[8]         M. Gandiglio, F. De Sario, A. Lanzini, S. Bobba, M. Santarelli, and G. A. Blengini, “Life cycle assessment of a biogas-fed solid oxide fuel cell (SOFC) integrated in awastewater treatment plant,” Energies, vol. 12, no. 9, 2019, doi: 10.3390/en12091611.

[9]         M. S. Romero-Güiza, J. Palatsi, X. Tomas, P. Icaran, F. Rogalla, and V. M. Monsalvo, “Anaerobic co-digestion of alkaline pre-treated grease trap waste: Laboratory-scale research to full-scale implementation,” Process Saf. Environ. Prot., vol. 149, pp. 958–966, 2021, doi: 10.1016/j.psep.2021.03.043.

[10]      S. Vinardell, S. Astals, K. Koch, J. Mata-Alvarez, and J. Dosta, “Co-digestion of sewage sludge and food waste in a wastewater treatment plant based on mainstream anaerobic membrane bioreactor technology: A techno-economic evaluation,” Bioresour. Technol., vol. 330, no. January, p. 124978, 2021, doi: 10.1016/j.biortech.2021.124978.

Ammonia Pollution


eleased data from the European Environment Agency shows how the emissions of most air pollutants are decreasing in the European Union, in contrast to the increasing ammonia (NH3) emissions from the agricultural section, which challenges the EU Member states to meet their air pollution limits.1

Ammonia is one of the most produced inorganic chemicals in the world, with an estimated annual global production of up to 200 million tons.2 Approximately 80% of the global ammonia production is used in the fertiliser industry,2 playing a key role in sustaining the exponential growth in human population in the last 50 years, as seen in Figure 1.3

Figure 1 – Portion of the global population supported by synthetic NH3 (in red), from 1900 to 2015.4

Despite our dependency on ammonia fertiliser, NH3 is a highly toxic chemical and undesirable NH3 emissions into the natural environment are responsible for damaging the biodiversity in aquatic and terrestrial ecosystems, as well as the human health. Exposure to high levels of gaseous NH3 has been associated to adverse health conditions in humans skin, lungs and eyes, and concentrations of about 3000 ppm can be fatal in roughly 30 minutes.5 Gaseous ammonia is colourless and it can combine with other contaminants present in the atmosphere, such as sulfuric dioxide, volatile organic compounds and nitrogen oxides, to form harmful small sized particulate matter, known as PM2.5.6 These PM2.5 can travel long distances (up to 1000 km).7 NH3-derived PM2.5 is responsible for causing adverse health conditions, as cardiovascular disease, asthma, lung cancer and premature death.7

In the past years, the increase in NH3 levels has been widely attributed to farming intensification. In this sector only, NH3 emissions increased by 90% between 1970 and 2005.8 It is estimated that more than 60% of the applied nitrogen-based fertiliser is not used by crops to grow.9 Nutrient loss is a major source of pollution and it is, in different extent, globally widespread. Another major source of ammonia emissions is produced by livestock manure.

In Europe, sixteen out of twenty-eight members had surpassed in 2016  their 2020 ammonia emission limits.10 Among which the most NH3-pollutant countries were in Latvia, Germany and United Kingdom.10

In UK, Northern Ireland (NI) alone is responsible for 12% of the total NH3 emission.11 The majority (94%) of these emissions originates from the agriculture sector, and in particular from cattle, which accounts for the largest portion (69%).12 Most of NI including priority habitats have a nitrogen concentration that causes significant and irreparable ecological damage. Northern Ireland Environment Link (NIEL) reported in 2019 that 90% of NI’s protected habitats, 98% of Special Areas of Conservation and 83% of special protected areas have exceeded critical loads of nitrogen deposition. Moreover, data released by Department of Agriculture, Environment and Rural Affairs (DAERA) shows significantly deteriorating water quality standards, with 95% of lakes not meeting the Water Framework Directive quality standards and nitrogen levels in both river and marine bodies rising in the past years.13

Some of the strategies that have shown to reduce emissions include: reducing food waste, changing crop allocation to maximise the gain in crop yield, investing in agriculture technology, supporting agricultural modernization, and using chemical nitrogen fertilisers effectively and efficiently.9, 10, 12 Ammonia pollution can be as well reduced by improving confined animal buildings and livestock raising techniques, with better design to sequestrate NH3, reducing the hazard for workers and the NH3 emissions to the atmosphere.11 Moreover, a careful slurry management, including artificial floating crust or a fixed cover, can also reduce ammonia emission up to 60%, during the storage.12

Ammonia emissions are a threat for humans and the natural ecosystems. There is an urgent need to reduce the impact of the agriculture sector, which represents the major source of NH3 emission in the natural environment. Further actions need to be implemented to prevent further biodiversity loss, prevent public health, and at the same time enable sustainable development.


1.           Air quality in Europe – 2020 report; European Environment Agency: 2020.

2.           Garagounis, I.;  Vourros, A.;  Stoukides, D.;  Dasopoulos, D.; Stoukides, M., Electrochemical Synthesis of Ammonia: Recent Efforts and Future Outlook. Membranes (Basel) 2019, 9 (9), 112.

3.           Smil, V., Detonator of the population explosion. Nature 1999, 400 (6743), 415-415.

4.           Erisman, J. W.;  Sutton, M. A.;  Galloway, J.;  Klimont, Z.; Winiwarter, W., How a century of ammonia synthesis changed the world. Nature Geoscience 2008, 1, 636.

5.           Birken, G. A.;  Fabri, P. J.; Carey, L. C., Acute ammonia intoxication complicating multiple trauma. J Trauma 1981, 21 (9), 820-2.

6.           Gu, B.;  Sutton, M. A.;  Chang, S. X.;  Ge, Y.; Chang, J., Agricultural ammonia emissions contribute to China’s urban air pollution. Frontiers in Ecology and the Environment 2014, 12 (5), 265-266.

7.           Asman, W.;  Sutton, M. A.; Schjørring, J. K., Ammonia: emission, atmospheric transport and deposition. New Phytologist 1998, 139, 27-48.

8.           Sommer, S. G.;  Webb, J.; Hutchings, N. D., New Emission Factors for Calculation of Ammonia Volatilization From European Livestock Manure Management Systems. Frontiers in Sustainable Food Systems 2019, 3 (101).

9.           West, P. C.;  Gerber, J. S.;  Engstrom, P. M.;  Mueller, N. D.;  Brauman, K. A.;  Carlson, K. M.;  Cassidy, E. S.;  Johnston, M.;  MacDonald, G. K.;  Ray, D. K.; Siebert, S., Leverage points for improving global food security and the environment. Science 2014, 345 (6194), 325-328.

10.         Giannakis, E.;  Kushta, J.;  Bruggeman, A.; Lelieveld, J., Costs and benefits of agricultural ammonia emission abatement options for compliance with European air quality regulations. Environmental Sciences Europe 2019, 31 (1), 93.

11.         Luke, J.;  Lucy, G.;  Courtney, S.; King, K. Air Pollution Inventories for England, Scotland, Wales, and Northern Ireland: 2005-2019; Department for environment Food and Rural Affairs: 2021.

12.         Code of Good Agricultural Practice for the Reduction of Ammonia Emissions; Department of Agriculture, Environment and Rural Affairs: 2019.

13.         Ciara, B.;  Laura, N.;  James, O.; Ekaterina, G. EJNI Briefing Paper Series Northern Ireland Assembly – Ammonia Pollution in Northern Ireland; Environmental Justice Network Ireland (EJNI): 2020.

Brine entering the Mediterranean, 300 metres off the coast of Israel. (Image: Hagai Nativ / Alamy)

Environmental Impacts of brine discharge from Desalination plant on…


owadays, the lack of freshwater is expanding with increasing the world population, urbanization, contamination, and environmental change. To keep up the equilibrium between water supply and demand; some strategies should be implemented. The best system to treat saline water is desalination. Desalination is a process of removing dissolved minerals and pollutants from seawater, brackish water, and treated wastewater Different desalination technology has been developed based on evaporation and membrane technology Table 1. 1 2


       Table 1 Desalination technology and mechanism 2

Most of the desalination plants are built on the coastline, where seawater is used to produce fresh water. The brine water (BW) is the byproduct of the desalination process and is discharged into the sea again by channels or pipelines. It has a high concentration of dissolved minerals, salts, and temperature compared to seawater. The brine characteristic depends usually on the type of feed water and desalination process, recovery percentage, and chemical used in the desalination process 2 3.

The BW has two different behaviors when it is dumped into seawater. The first behavior is near the discharge point, and it is called the near field region behavior. The second behavior is far from the discharge point, and it’s called the far-field region behavior. The Near-field region depends on the design of the brine discharge system, which is intended to increase the dilution rate at this region. The Far-field region is located far from the discharge point, where the brine is flowing down the seabed due to gravity current. In far regions, the brine mixing with seawater depends on ambient conditions and density differences between the Hypersaline brine and the receiving seawaters.

Figure 1 shows the near and far-field region 1.

BW discharge to seawater can cause a change to seawater salinity, alkalinity averages temperature, and can cause a change in the marine environment. The BW characteristic usually depends on the type of feed water, desalination process, recovery percentage, and chemicals used in the desalination process. Also, Brine discharge into seawater has several environmental impacts on marine life.4

The List of the environmental Impacts of a desalination plant on the seawater environment includes salinity, Temperature, Dissolved Oxygen, Chlorine Concentration, unionized ammonia, and Seawater Intake.

BW Salinity can lead to an increase in the seawater salinity level near the discharge point.  The negative effect of brine discharge occurs with the sensitive marine ecosystems 3 4. According to the Medeazza study, changes in the salinity of seawater have a potential to heavily affect marine biota. Changes in Seawater salinity affect the propagation activity of the marine species, their development, and growth rate. “Larval stages are very crucial transition periods for marine species and increasing salinity disrupts that period significantly”  5 6.

Also, some of the desalination plants are combined with power plants. Power plants produce water effluent at high temperatures. These water effluents are mixed with BW from the desalination plant and discharged into seawater causing an increasing the seawater temperature between 7 °C to 8 °C. The raises in the seawater temperature leading to a change in species composition and abundance in the discharge region. 4 6

Seawater dissolved oxygen level is a very important factor and depends on the temperature. By increasing the temperature of the seawater near the discharge point, the amount of dissolved oxygen will decrease. That causes Hypoxia, which is resulting from the low level of dissolved oxygen concentration in water, and it can cause serious damage for the marine life 6 4

Moreover, the presence of high chlorine concentration in BW can lead to the formation of hypochlorite and hypobromite in seawater, which affect seawater quality and the ecological system. Chlorine affects the fish and marine invertebrates can cause burns in both of them and resulting in serious damage to the marine organisms (Boumis). 4

Ammonia substances and un-ionized ammonia are very toxic to marine life. The ratio of ammonia substance and un-ionized ammonia are PH dependence. With increasing the PH, the concentration of both ammonia substance and un-ionized ammonia increases. The concentration of both ammonia substance and un-ionized ammonia in the discharge region depends on the size of the plant and the ambient seawater conditions. Usually, the concentration of ammonia substance and un-ionized ammonia should meet the water quality standard because they are very toxic and harmful for marine life 4 (Mohamed 2009).

Seawater Intake has the most impact on marine life.  Substantial Seawater intake can be very harmful to marine life, by causing Entrainment & impingement. Impingement happens when large organisms such as fish are pulled into the water intake pipe and looked in intake pipe mesh, causing death or injury of these organisms. Entrainment happens when small organisms pulled into the water intake pipe and pass the intake pipe mesh to feed the water tank, causing the death of these organisms in a pre-Chlorination process 6

Nowadays, the continuous increase of water desalination plant numbers led to the development of methods and processes to minimize the negative impact of BW discharge. There are many strategies for decreasing the negative impact of brine discharge. The main strategies include BW treatment before discharge and redesigning the desalination plant.6

Desalination plant brine can be treated before discharging into seawater to reduce the impact on the marine environments. In brine discharge into the seawater surface, outfall diffusion devices such as diffusion nozzles can be used to dilute the brine with the surface seawater. Also, the brine can be diluted with treated wastewater before the discharge into seawater. Further, the brine can be evaporated naturally by spreading it in pools and reused the solids lefts. These strategies are suitable for small and medium-sized desalination plants. It reduces the salinity of the brine and decreases the negative impact on the marine environment 6 7 8

The environmental impact for desalination plants can also decrease by designing them in a sustainable way and by installation mechanisms reduces their negative impact. Beach wells or infiltration galleries are one of the mechanisms that are used to reduce the negative impact. Beach wells or infiltration galleries work as a natural filter for feed seawater. It keeps out the marine organism, increases the quality of feed water, reduces the cost of pretreatment and Impingement, and entrainment. Jet brine release is another mechanism that can be added, where the brine released at an angle of 30-45⁰ can enhance brine mixing and offshore transport in coastal water. This leads to a decrease in the intensity of brine plumes resulting in a decrease in the salinity level 8 9.

However, BW management is on from the biggest challenge economically and environmentally. But Still, BW monitoring and quality standards should be applied in the desalination plant. More research and development in the field of brine impact on the environment and processes to reduce this impact should be further investigated. Research and comprehensive studies to minimize the negative impact of desalination plants should be carried out in water research centers and water authorities.


1.      Palomar P, J. I. Impacts of Brine Discharge on the Marine Environment. Modelling as a Predictive Tool. In: Desalination, Trends and Technologies. ; 2011. doi:10.5772/14880

2.      Danoun R. Desalination Plants: Potential impacts of brine discharge on marine life. Final Proj Ocean Technol Gr. 2007.

3.      Panagopoulos A, Haralambous KJ. Environmental impacts of desalination and brine treatment – Challenges and mitigation measures. Mar Pollut Bull. 2020. doi:10.1016/j.marpolbul.2020.111773

4.      Dawoud MA. Environmental Impacts of Seawater Desalination: Arabian Gulf Case Study. Int J Environ Sustain. 2012. doi:10.24102/ijes.v1i3.96

5.      Meerganz von Medeazza GL. “Direct” and socially-induced environmental impacts of desalination. Desalination. 2005. doi:10.1016/j.desal.2005.03.071

6.      Ahmed M, Anwar R. An Assesment of the Environmental Impact of Brine Disposal in Marine Envirnmento. Int J Mod Eng Res. 2012;2(4):2756-2761.

7.      Castillo RS, Maria J, Sanchez S, Castillo NS. Brine Discharge Procedures to Minimize the Environmental Impact and Energy Consumption. October.

8.      Salt HITS. Desalination: is it worth its salt? A Primer on Brackish and Seawater Desalination. 2013;(November).

9.      Laspidou C, Hadjibiros K, Gialis S. Minimizing the environmental impact of sea brine disposal by coupling desalination plants with solar saltworks: A case study for Greece. Water (Switzerland). 2010. doi:10.3390/w2010075

The leading-role in food production: phosphorus rocks

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


t 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.


[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.

Mountain ecosystem restoration for disaster mitigation in Pakistan


xtreme events associated with the universe are older than human origin on earth and they have coexisted with old civilizations (Khan & Khan, 2008), while during the first half-decade of the twenty-first century, great human influences in incidents of disasters have been observed. Irrespective of location, hazards of multitude nature threaten mankind (Pinkowski, 2008). Climate change today is a serious issue all around the world and a biggest challenge posing threat to the people and economies. IPCC (Inter-governmental panel on climate change) assessment report shows that crop yield rates are declining in most parts of the world, due to the consequences of rising temperatures, while prevalence of climate induced diseases has been observed too. Fresh water availability is at risk, especially in large river basins and it is anticipated that, it may impact billions of people by 2050s (Ashraf, 2014).

Pakistan holds a complex and remarkable physiographical features that include the Northern high mountain ranges (Karakurum, Himalayas, Hindukush), the snow covered peaks, western bordering highlands in the north, the salt range and Potohar plateau, Indus plain and the Baluchistan plateau (Earthquake Review, 2011). Pakistan, despite contributing less to natural disaster driving phenomenon, such as greenhouse gases, has been among the top ten most affected countries worldwide. Events like the phenomenal floods (2010) that submerged one fifth of the country, displacing millions of people and changing monsoon pattern is just a single example of natural disasters in Pakistan.  Climate change is expected particularly to affect the agriculture sector in Pakistan (Ashraf, 2014).

Figure: A problem tree indicating some of the causes and impacts of natural disasters in mountain areas.

The mountain regions of the world pose special challenges to sustainable development. They tend to be ecologically fragile; highly variable in terms of precipitation, temperature, and other factors; and prone to landslides and other natural disasters. Local communities are often dispersed, situated in remote locations, and economically and socially marginalized from national development processes (IUCN, 2003), but there are huge benefits associated with these regions. They are the protector of water catchments, and they have unique cultural as well as biodiversity assets. These areas are rich in natural resources. Managing the problems of hazards in these areas and enhancing capacities in the communities has become crucial.

Some 25 percent of the earth’s surface is mountainous, inhabited by 26 per cent of world’s population, and are source of fresh water for more than half of humankind. The crisis is due to cultural, ecological, social and economic changes at faster rates. Moreover, population growth, infrastructure development, deforestation, over-grazing, agricultural expansion, climate change and violent human conflicts all threaten this fragile environment. In 1992, the special needs of mountain regions were taken into account in the form of the Agenda 21, “Managing Fragile Ecosystems: Sustainable Mountain Development.” In 2002, the year was declared as the International Year of the Mountains. The year culminated in the Global Mountain Summit and adopted at the Bishkek Mountain Platform (IUCN, 2003). Reports by IUCN in the mountain areas of Pakistan situated in the Northern areas show that these areas are confronted by a wide array of problems and threats. Natural resources such as forests and biodiversity are being degraded; food security is diminishing; women’s workloads, poverty and vulnerability are on the rise; energy supplies are insufficient to meet demand; drinking water supplies are inadequate and frequently contaminated; and access to health and education services remains constrained by many factors. Although the report was drafted more than a decade back, the current situation indicates little improvement and needs further actions. This area remained unrepresented in national political forums.

This year, Pakistan hosting the World Environment Day 2021 is a great opportunity to recognize the importance of a healthy mountain ecosystem for sustainable development in Pakistan. The theme of World Environment Day 2021 is Ecosystem Restoration, and in the context of Pakistan, the mountain areas, housing diverse biodiversity and the fresh water sources require special attention. The slogan: “Recreate, Reimagine, Restore”, further calls for resource allocation and involvement of local communities in the environmental protection. Managing the human impacts on the mountain ecosystem also holds greater promises in mitigating the natural disasters. Because, the mountain areas of Pakistan are predicted to receive greater climate change impacts, one reason being the presence of high number of glaciers in the area. Furthermore, the local communities’ access to alternative economic sources will decrease the human dependence on natural resources and degradation of the environment.


Khan, H., & Khan, A. (2008). Natural hazards and disaster management in Pakistan.

Pinkowski, J. (Ed.). (2008). Disaster management handbook. CRC Press.

Ashraf, A. (2014).  The changing climate. Pakistan Today Magazine, 4, 286.

Government of Pakistan & IUCN. (2003). Northern Areas State of Environment and Development. IUCN Pakistan, Karachi, 301.

Earthquake Reconstruction and Rehabilitation Authority.(2011). Earthquake Review.