Biogas as an energy source is becoming more and more popular, but what is biogas and how does it differ from natural gas? The difference is that natural gas is a fossil fuel, while biogenic gas is renewable.
Natural gas was formed millions of years ago, at the age of the dinosaurs, like oil or coal. The accumulation of plankton as well as animal and plant rests on the seabed, buried by layers of soil, caused it to be produced in anaerobic conditions, that is, without oxygen.
Biological bacteria decomposed the organic matter and the gases generated bubbled upwards, and where there was an impermeable layer, they accumulated, giving birth to gas pockets or reservoirs. It is therefore a finite resource; once it is exhausted, there will be no more to supply human energy demands.
Natural gas consists mainly of methane, ethane and carbon dioxide, although it usually has other components or impurities, so the energy is obtained by combustion, compared to other fossil fuels it is more efficient and cleaner in terms of emissions, although it depends on the impurities.
Biogenic gas is also produced by the decomposition of organic matter under the action of bacteria, in the absence of oxygen, which is why it is also called Biogenic Natural Gas, but in this case in a tank with controlled conditions of temperature and pressure.
But in biogenic gas, the organic matter used comes from by-products of farms, crops or industries, so it is a renewable energy. The composition of biogenic gas is similar, but with fewer impurities, as the quality is improved by upgrading, which is explained in this blog post.
Moreover, natural gas is thousands of kilometres away, but biogenic gas can be produced in small tanks for self-supply, e.g. on a farm, or on a large scale in a sewage treatment plant, and existing natural gas pipelines can be used.
It may seem to be all advantages, but this is not the case, which is why CARTIF organised the first meeting of the Community of Practice within the Horizon Europe CRONUS project on 20 March 2024.
The Communities of Practice consist of the grouping of different actors in the biogas sector, such as universities, research centres, producers or distributors, among others, and act as spokespersons for the sector for both citizens and administrations, assessing the strengths and weaknesses, facilities and barriers to the use of biogas in order to make responsible use throughout the value chain.
At this first meeting, three main challenges were addressed:
Raw materials
Technology
Regulations: Logistical, Productive, Social
THE FIRST CHALLENGE, RAW MATERIALS
In the first challenge, the issue of raw materials was addressed. At present, there are no problems in finding them, but there are problems in obtaining supplies, the question is: is this a logistical or quantity limit? In terms of accessibility, it is not as accessible in the mountains as it is on the plateau, and in terms of plant and supplier size.
There is also concern that, in the future, due to the law of supply and demand, both raw materials and transport will reach exorbitant prices. It is necessary to start regulating and organising the market to ensure a supply where the whole value chain benefits.
It is important to consider the methanogenic potential, i.e. how much gas a plant can produce with a given raw material, this determines its viability, therefore the raw materials must meet certain standards and heterogeneity all year round, in order to obtain a constant production, both in quality and quantity.
This leads to the question of the suitability of single or multiple feedstock feeding. In some cases, it is necessary to pre-treat these feedstocks and due to the technical complexity they are not cost-effective, so having flexibility in the use of feedstocks is an advantage.
The most worrying aspect is the injection into the grid. There are problems when it comes to incorporating the gas produced into the existing national distribution network, which in some cases favours the self-consumption of gas, but in others, the waste of this energy source is wasted.
It is a mature technology, but there is still innovation to be done, especially with the bacteria, points of improvement such as new strains are still being discovered, and they make the process and therefore its efficiency is much better known.
In the end, it is an investment, so it is necessary to conscientiously measure the risk and profitability vs. administrative and legal barriers, and although more and more people are opting for it, there would be more if there was a financial push with subsidies, but they would not be the basis of the product.
THE SECOND CHALLENGE, TECHNOLOGY
The second challenge was to know the opinions about the FP5 prototype that is being developed in CARTIF within the CRONUS project. That can be seen in this video.
The expert assistants pointed out that it competes directly with upgrading, so it may not be economically viable on a large scale, but for small plants, it is a good solution, as it does not need to undergo such a large purification process.
On the other hand, it needs a hydrolysis stage, which requires energy, but it is a self-sustainable process, so it is able to be self-sufficient. Technology must favour profitability, as money is always a constraint, both for development and production.
Its strong point was highlighted, which is that it can valorise and reduce the CO2 generated in the AD, obtaining a higher quality biomethane than through traditional processes, especially because cogeneration is more interesting than gas for sale.
As it is the first meeting only the laboratory prototype could be seen, so they perceived that there could be problems in the scaling in the electrodes, as they have to be larger, and there is no microbial electrolysis cell-assisted anaerobic digestion technology (MEC-AD) on the market, but CARTIF already commented that there are more options to integrate MEC-AD in the digester.
It also raised the possibility of problems with having to restart the plant, after a shutdown, which can be slow and complex, but it is a continuous system so it will not be so slow.
The Community is optimistic about CARTIF’s FP5 prototype and is looking forward to seeing its progress in the next calls for proposals.
THE THIRD CHALLENGE, REGULATION: LOGISTIC, PRODUCTIVE, SOCIAL
This challenge is where there was the greatest participation and unanimity. It seems that the Public Administration is not advancing as fast as biogenic gas is. One barrier is the processing time, which can take up to 3 years for project approval, to which environmental authorisations must be added, and the time dedicated to the plant’s engineering project.
This could be favoured with legislation that favours self-consumption, such as premiums or payments for the generation and sale of energy. It would be interesting to map waste production throughout the country.
In the case of Castilla y León, there is the obligation to become an authorised waste manager and limitations on the maximum distance allowed for the transport of digestate, as in the transport of slurry, which shows that the administration is prepared.
But the definition of waste needs to be revised, in order to revalorise by-products for use in anaerobic digestion and also the resulting digestate as it has many potential uses, such as stripping/scrubbing or crystallisation of struvite, which can even be considered as an environmentally friendly product, as fertiliser.
Raw materials, such as slurry, must be used responsibly due to the contamination of aquifers by nitrates, so the use for biogas generation is a solution for this waste, and the resulting digestate could be revalued as fertiliser or as an ingredient for compost.
The growing demand for biogas highlights the need for the modernisation of farms to increase their income from the sale of waste and reduce energy costs by using biogas.
On the other hand, there is a need for the Administration to update its technicians with specific training, since, when evaluating a project, there is no clarity in the criteria, standards and administrative procedures to be applied, and there are differences between technicians.
In short, more support is needed from the Administration, especially with the private companies that control the distribution networks and establish the technical and economic requirements for connection and injection into the network, resulting in abusive technical and economic conditions. The Community of Practice considers this barrier easy to remove.
There is a lack of dissemination and knowledge, which is why citizens associate it with bad smells, noisy lorry movements and a lack of safety, which is why the Community of Practice is doing a good job of disseminating and raising awareness in society of how biogenic gas works and the technology associated with it.
There are both urban and rural barriers, each with its own complexity, in addition to the fact that each Autonomous Community has its regulations in this regard, so each plant in each area must be approached individually, through conferences, citizen participation, a network of interaction with citizens in other areas that already have this technology in place, but above all with transparency.
The reality is that the development of biogenic gas will contribute to rural repopulation, job creation, as well as energy production and the development of the Circular Economy, which is a pending issue in the 2030 agenda.
The majority of plastics used in the world today come from non-renewable and non-biodegradable sources. In an effort to reduce the impact of plastics on the environment, alternative methods of production and waste management have been studied for decades. Several microorganisms have the ability to produce plastics naturally, using different substrates, which are biodegradable and biocompatible under certain conditions.
During the last few years, acidogenic fermentation for the production of volatile fatty acids (VFA) has been identified as a promising approach to utilise organic waste as a valuable resource. VFA have a wide potential for applications ranging from carbon source for biological nutrient removal processes to use as a bioenergy resource for the generation of hydrogen and liquid biofuels. VFA-rich streams produced from organic waste fermentation can also be used as biopolymer precursors in the bioplastics industry, as they are a suitable feedstock for the production of polyhydroxyalkanoates (PHA).
To address the growing problem of bio-waste generation and the increasing demand for bio-based feedstocks, the ELLIPSE project is working in the biotechnology sector with the aim of valorising heterogeneous waste streams generated in significant quantities in Europe, slaughterhouse waste (contained in the belly or rumen) and paper and pulp sludge, to produce cost-effective polyhydroxyalkanoates (PHA) for agricultural and personal care applications, through co-processing with other organic wastes such as sludge from the dairy industry and glycerol from the biodiesel industry, as well as nutrient recovery to produce bio-based fertilisers. The integration of these waste streams as biorefinery feedstocks will reduce landfill waste volumes, open up new pathways for the production of chemicals and bioplastics and, at the same time, create additional income for the related industries that generate them, with the added benefits of water recycling, reduced soil degradation, groundwater contamination and methane emissions.
PHA belongs to a family of 100% bio-based polymers with versatile biodegradability properties in most environments, recyclable and exhibiting a wide range of physical and mechanical properties depending on their chemical composition, from the very flexible poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) to the rigid polyhydroxybutyrate (PHB), showing similar properties to some fossil-based materials such as polypropylene (PP) and polyethylene (PE) and better gas and liquid barrier properties than other bioplastics such as polylactic acid (PLA), being a good biodegradable and compostable alternative in agricultural and personal care applications.
One of the objectives is to maximise the production of VFA derived from acidogenic fermentation by optimising the process using innovative technologies, such as the use of an anaerobic membrane bioreactor (AnMBR). The project contributes to the circular economy by promoting sustainability and zero waste by demonstrating the technical feasibility of recovering nutrients from the waste stream (digestate) through a hybrid autotrophic-heterotrophic process of microalgae cultivation, which results in the production of a biofertiliser.
The project has 5 phases dealing with pre-treatment of waste and obtaining VFA, production of PHA, possible applications of bioplastics, life cycle analysis study and exploitation of the results.
Pliot plants of the ELLIPSE project
In Pilot 1, pre-treatment and valorisation of sludge from the processing of slaughterhouse waste for the production of rigid packaging and plastic mulch will be carried out. A co-digestion of raw materials will be carried out in order to ensure the most optimal conditions for producing VFA.
Pilot 3 will be developed simultaneously with Pilot 1 to recover N and P nutrients for biofertiliser production. Different technologies will be validated:
The biological technology of the hybrid autotrophic and heterotrophic microalgae culture system, and the physical methods of pressure-drive membrane technology (ultrafiltration and reverse osmosis) and membrane contactors, to recover ammonia, as ammonium sulphate.
Pilot 2 will treat and recover waste from the paper industry to produce bioplastic coatings for the personal care and agricultural sectors.
The demonstration of the possibility to transform complex bio-waste stream into high-value bio-based and biodegradable products in multiple sectors, accompanied by the validation of multiple end-of life routes for the biobased and biodegradable products achieved within the project will provide novel and tangible results for further promoting public awareness and acceptance of biodegradable and bio-based solutions. Apart from all this, during ELLIPSE project the pulp and paper industry will be able to utilize products (PHA coated paper for flexible packaging as counterpart of current PE coated paper) produced from its wastes. This is a good showcase for circular economy and has the potential to increase awareness and acceptance of bio-based solutions.
When we think in agriculture, we often focus on the development of the plant, but we rarely consider the importance of proper management of the soil in which crops are grown. Soil is a vital resource that sustains our lives and provides the food that is indispensable for humanity, and its health is essential for sustainable agriculture and food security.
At first glance, soil may appear lifeless, but in reality, it is teeming with microscopic life. Healthy soils harbour a wide variety of microorganisms, including bacteria, fungi, protozoa, nematodes, etc. These organisms, which often go unnoticed, play an essential role in the functioning of terrestrial ecosystems.
Among the soil-dwelling microorganisms, many are beneficial to plant health soil quality in general. These microorganisms perform a number of vital functions:
1. Decomposition of organic matter: microorganisms break down organic matter in the soil, such as fallen leaves and plant debris. This action releases essential nutrients that can be absorbed by plants to support their growth.
2. Nitrogen fixation: nitrogen is one of the most important nutrients for plant growth. Some bacteria have the ability to fix atmospheric nitrogen in a form that plants can metabolise.
3. Protection against pests and diseases: some microorganisms act as biological control agents, helping to prevent plant diseases by competing with pathogens or producing antimicrobial compounds.
4. Improvement of soil structure: other microorganisms, such as bacteria or fungi, generate soil aggregates that improve soil structure, porosity and water holding capacity.
5. Nutrient cycling: they participate in the decomposition and release of essential nutrients, such as phosphorus, potassium and various micronutrients (zinc, iron, copper, calcium), which are essential for plant growth.
Unfortunately, modern agriculture has engaged in practices that often damage the diversity and population of beneficial microorganisms in the soil. Excessive use of chemical fertilisers and pesticides, intensive tillage and lack of crop rotation are practices that can damage or unbalance the microbial ecosystem present in the soil.
For example, chemical fertilisers may provide nutrients to plants, but they can also lead to soil acidifcation and negatively affect beneficial microorganisms. Similarly, pesticides intended to kill pests can negatively affect other microorganisms in the soil, which can trigger a cycle of dependence on agricultural chemicals.
Fortunately, there are agricultural practices that can promote soil health and the abundance of micro-organisms that play a positive role in plant development:
Organic farming
Organic farming avoids excessive use of chemical pesticides and fertilisers, which preserves the microbial ecology of the soil.
Crop rotation
Changing crops season after season encourages microbial diversity and avoids the build-up of specific pathogens.
Use of cover crops
Maintaining a vegetative cover on the soil throughout the year helps to maintain microbial activity and prevent erosion.
Composting
Adding organic compost to the soil enriches the microbial population and provides nutrients in a balanced way.
Reduced tillage
Minimising soil tillage reduces the disruption of microorganisms in their natural environment.
Use of green manures
Planting green manure crops such as legumes can increase nitrogen fixation and enrich the soil in nutrients.
Soil health is fundamental to agricultural sustainability and global food supply. Beneficial microorganisms, working in symbiosis with plants, play an essential role in preserving that health. As a society, we must recognise the importance of
these tiny creatures and adopt practices that promote their thirving in our soils.
At CARTIF, we have the experience gained through the implementation of several projects related to the proper management of microbiology applied to agriculture and especially to soils, either in the form of biofertiliser (SUSTRATEC proejct) or in the form of biopesticide (SUPERA project).
Maintaining soil health is not only essential to ensure abundant and nutritous harvests, but also to preserve biodiversity and mitigate climate change. By protecting and nurturing life in the soil, we are investing in a healthier and more sustainable future for our planet and future generations. Let us care for the land that cares for us.
This past month (june 2023), eurodeputies provisionally agreed on new legislation for batteries sold in the EU. It has already been hailed as a “game changer” for batteries, creating a framework to foster a competitive and sustainable battery industry in Europe.
After lengthy negotiations, the European Parliament adopted the EU Battery Regulation on 14 June. Batteries are a key technology that plays a fundamental role in moving towards a climate-neutral Europe by 2050. In this context, the Battery Regulation is a key achievement of the European Green Pact, under which all 27 member states have committed to making Europe the first climate-neutral continent by 2050.
But what exactly is the European battery regulation, and what do manufacturers need to do to stay ahead of the regulations?
Proposed initially in december 2020, EU Regulation about batteries are progressive requirements to guarantee that all comercialized batteries in these countries are more sustainable, circular and save along its entire life cycle. For electric vehicles and industrial batteries with a capacity superior to 2kWh, the requirements relapses mainly in battery manufacturers and are divided into (1) guarantee supply practices more transparent and accountable and (2) facilitate circular economy (see Figure 1).
Figura 1: Highlights of the European Regulation about batteries
Go ahead the events. How can companies response to fulfill the next regulation
Regulation shall enter into force in 2024, what means that companies has to act now to establish the need bases to fulfill and overcome the requirements:
Know all the impacts
While batteries are obviously more sustainable than fossil fuels, they are not exempted of negative impacts. While carbon emissions receive the most attention, the impacts associated with battery supply chains are much broader- from water use to child labour and end-of-life waste- and this is one of the driving forces behind the scope of the EU Battery Regulation.
Companies will therefore need to understand the wide range of environmental and social impacts of their direct operations and supply chains. And to adequately measure, reduce and/or eliminate propperly these impacts, companies must develop specific and tailored strategies based on their current performance and processes.
Prioritising supply chain collaboration
While battery manufacturing itself is often a high impact process, many of the sustainability impacts associated with batteries can be found in the supply chain, such as carbon emissions from the extraction and refining processes. Therefore, it is not only the data that is important for companies to comply with regulations, but also the processes and systems to manage and improve the sustainability of the supply chain.
The EU Battery Regulation has taken this into account by setting requirements for all economic operators placing batteries on the European market (except small and medium-sized enterprises) to develop and implement due diligence policies in line with international standards. Battery manufacturers will therefore have to implement communication and collaboration systems with suppliers, such as sustainability questionnaires for suppliers, continuous sharing of results, audtis of high-risk suppliers and improvement programmes.
Reporting, improving and being prepared for comparison
Once companies understand their impact and put systems and processes in place to improve the sustainability of their company and supply chain, they must report on their results. Standardised reporting is a key component of sustainability legislation, and the EU Battery Regulation is no different.
Because reporting drives benchmaking and provides stakeholders with greater decision-making power, the EU Battery Regulations are intended to create the necessary incentives for companies to improve their sustainability performance. Battery manufacturers can prepare for this developing a systematic approach to reporting that allows them to effectively communicate their impacts, their progress and how they relate to others in the sector.
Where we are going?
EU Battery Regulation is part of a broader set of global standards aimed at improving the sustainability of the battery industry. EU regulators have yet to formally approve the regulation and develop guidelines for its implementation. However, battery manufacturers that want to differentiate themselves and be leaders in sustainability must act now. In short, they can do so by investing their resources in understanding their sustainability impact alongside regulatory requirements, managing and improving their supply chain sustainability processes and reporting their progress in a standardised way. While this may seem daunting, there is still time to act.
If you found this content interesting, you can follow the progress of FREE4LIB project, coordinated by CARTIF, which is fully alligned with the new Battery Regulation.
I think most people are familiar, in one way or another, with the characteristics of the chemical elements we are going to talk about in this post: nitrogen (N) and phosphorus (P). Nitrogen in its gaseous from (N2) is part of the composition of atmospherica air or we even know it in another of its typical forms, ammonia (NH3), either as a gas or as a liquid solution (in this case as ammonium NH4 ). Phosphorus, on the other hand, is involved in vital functions in living organisms, as well as being one fo the main components of RNA and DNA molecules and is used to store and transport energy in the form of adenosine triphosphate (ATP). Well, today in this post we are going to go deeper into why these two elements are also important for other issues related to human beings and their development, we will explain the importance of nitrogen (N) and (P) as agronomic nutrients and how they are related to the concept of Circular Economy (a concept that has been very topical in recent years). Therefore, from now on, when we talk about nutrients in this post, it will always be focused from an agronomic point of view and nto from a human food point of view. Let´s start!
Both nitrogen (N) and phosphorus (P), together with potassium (K), form the group of agronomic macronutrients, which are the three main macroelements that plants or crops need to incorporate for their growth. Thus, in most cases, the fertilisers that are synthesises, and used nowadays in agriculture have an important composition of these elements (we usually talk about the NPK content in these products).
The first uestion to ask is how are these fertilisers synthesisesd?
Almost all of the N used in the formulation of fertilisers is obtained from the synthesis of ammonia, the classic procedure for obtaining ammonia being the Haber-Bosch process. Subsequently, the ammonia obtained by the Haber-Bosch process is oxidised to give rise to nitric acid (HNO3), from which the main mineral fertilisers can be obtained, synthesised from ammonium nitrate [(NH4)NO3]. The other main source of N for fertilisers synthesis is urea [(NH2)2CO]. As far as phosphorus is concerned, the main raw materials for its use in fertilisers is apatite, which is a set of minerals obtained through the extraction of the mineral phosphate rock. Therefore, the first thing we can realise is that, in both cases, the origin of N and O for obtaining traditional fertilisers is a non-renewable origin.
In addition to this, there is another factor of great importance, namely the increase in the world´s population. According to United Nations (UN) forecasts, the world population will reach 8.6 billion in 2030 and 9.8 billion in 2050. It is clear that these facts will lead to a significant increase in pressure from the food industry, which will be forced to increase its production, leading to more intensive agricultural practices and therefore an increase in land use and consumption of water, energy and traditional non-renewable fertilisers. Another worrying fact abut this scenario is that the countries of the European Union (EU) are tremendously dependent on imports of these compounds that act as raw materials fot fertilisers. To give you an idea, the EU imports around 30% of the N, more than 60% of the P and 70% of the K of the ttal nutrients consumed as fertilisers products in its countries. This issue is even more dramatic in the case of P, as five countries worldwide hold 90% of the world´s reserves (China, Morocco, South Africa, the United States and the Jordan region). This has led the EU to classify P as a Critical Raw Material (COM(2017)490), as it is crucial for the EU´s own growth, competitiveness and especially for a sustainable food industry.
Against this backdrop, it is clear that the search for and introduction of alternative and renewable soruces of N and P, as well as novel technologies for the production of sustainable fertiliser products, is necessary.
And this is where the Circular Economy comes into play, on the one hand, and the concept of nutrient recovery on the ohter. Nutrient recovery is one of the main lines of research that we have been developing in recent years within the Circular Economy area of the CARTIF Technology Centre. Nutrient recovery consists of the development of methodologies, techniques and technologies that make it possible to obtain the N and P they contain from sustainable raw materials and that these elements are in a convenient and effective form for their subsequent use in the synthesis of bioproducts or sustainable fertilisers that can replace traditional mineral fertilisers or, failing that, increase the renewable component in the synthesis of the latter. It is important to highlight that, although nutrient recovery is mainly focused on the recvery of N and P, the recovery of ther agronomic macro and micronutrients, such as K, magnesium (Mg), calcium (Ca) ,etc., can also be achieved.
So what raw materials or sources of renewable origin can we use for nutrient recovery?
Nutrient recovery mainly focuses on two groups: agricultural and livestock waste and wastewater. By agricultural and livestock waste we mean any waste generated directly by agricultural or livestock activity (manure, slurry,etc.), as well as wastewater (both urban and industrial). In addition, and related to the above, biological waste or by-products obtained in the treatment of such waste could also be used in the recovery of nutrients (a clear example would be the digestate obtained from the treatment of such waste by anaerobic management of the sludge obtained in wastewater ttreatment processes in Wastewater Treatment Plants (WWTPs),etc.).
An important aspect to highlight is that nutrient recovery technologies depend to a large extent on the characteristics of the raw material we use to recvoer N and P and how this raw material is presented (in solid or liquid state). Thus, the simplest methods of nutrient recovery are the direct use as fertilisers of solid wastes or by-products such as activated sludge or manures and digestate or the composting of these. However, logistical aspects (cost of transport and management of the waste, which often contains high moisture) can make the process unfeasible. At the same time, direct application of the waste does not provide effective fertilisation and can lead to overfertilisation phenomena that can trigger eutrophication phenomena (due to the accumulation of N and P present in the soil that has not been assimilated by the crop and can subsequently be washed away by rain or run off and finally deposited in aquifers and bodies of water), with the consequent environmental damage. In additionm the residues may contain significant cmounts of potentially hazardous contaminants, which need to be removed prior to their use as fertilisers. For this reason, waste treatment technologies for N and O recovery are becoming increasingly popular. There are different technologies to recover N and P from liquid wastes, such as biological treatments, stripping, crystallisation, membrane filtration, thermochemical methods (pyrolysis and gasification) or physical treatments (concentration, drying,etc.).
But as all this is best understood with an example, we will try to explain one of the processes in which we have investigated in CARTIF some of our projects.
It is the recovery of nutrients from crystallisation. Crystallisation is a separation operation frequently used in Chemical Engineering, thanks to which purification of fluids is produced through the formation of solids, taking into account the solubility of the products that are of interest for their separation. Thus, crystallisation can be used to recover N and P from wastewater or liquid agricultural and livestock waste (liquid phase of digestate and manuse or slurry) in the form of struvite.
But, wait a minute, let´s take it one step at a time, what is struvite?
Struvite
Struvite is a salt (mineral orthiphosphate) containing magnesium, ammonium and phosphate in equal molar concentrations, specifically, struvite in the form of magnesium ammonium phosphate hexahydrate has the following molecular formula MgNH4PO4-6H20. Struvite crystallisation occurs easily when the ideal conditions are met (presence of a significant Mg, N and P contract, pH,etc.). In fact, struvite gained public attention in the 1960s as a result of the clogging of pipes in WWTPs, in which it crystallised spontaneously.
And now, we may think, okay, we know what struvite is, but how is it obtained?
The waste to be used as a raw material to extract N and P (normally wastewater or digestate obtained from the anaerobic digestion of waste such as pig slurry) is simply introduced into a crystallisation reactor and a certain amount of magnesium is added (normally in the form of MgCI2 or MgO) and depending on the pH of the reaction mixture, a base (NaOH) can be added to raise the pH (8-9). Once all the components are in the reactor, agitation (either mechanical or by aeration) is applied.
The Mg comes into contact with the N and P of the raw material and little by little the struvite crystals grow, according to the following chemical reaction:
After approximately one hour of reaction, most of the P contained in the raw material (and an equivalent amount of N and Mg) is recovered in the form of a whitish solid crystal, struvite. This solid has very good properties for use as a fertiliser, as struvite has a high concentration of P and, due to its physical characteristics (low solubility), the product can be used as a slow-release fertiliser, i.e., unlike traditional fertilisers, struvite releases nutrients according to the needs of the plant and its stage of growth, making it a more effective fertiliser and avoiding eutrophication and similar phenomena.
There are several struvite crystallisation technologies on the market (with different configurations, reactor types, morphologies,etc.), most of them focused on obtaining struvite from wastewater, however, in CARTIF we have developed a 50L pilot crystallisation reactor, trying to solve the technical impediments presented by other technologies. This crystalliser consists of a fluidised bed reactor,i.e. the agitation of the reaction mixture is achieved in suspension, facilitation their interaction and favouring the formation and growth of the crystals. The struvite crystalliation technology we have developed has been tested in several projects in which we have participated, such as Nutri2Cycle and Nutriman (both European projects of the Horizon2020 programme), with very promising results in the crystallisation process (achieving P recovery yields of voer 90%) and good agronomic performance of the final product obtained (struvite).
Nutrient recovery process at the demonstrator on Ireland of NUTRI2CYCLE project.
Therefore, as we have seen, thanks to nutrient recovery technologies we have developed sustainable processes in which we recover waste (wastewater, digestate,etc.) following the principles of the Circular Economy and we obtain a biofertiliser of renewable origin with good agronomic performance and with characteristics that are not present in traditional fertilisers of non-renewable mineral origin (slow release). Therefore, struvite would be a good candidate to replace or reduce the use of non-renewable fertilisers.
Currently in the Circular Economy Area of CARTIF, we continue working on the development of this line of research and we are currently coordinating the WalNUT project (another European project of the Horizon2020 programme), in which together with 13 other partners from several European countries we are developing new technologies for the recovery of nutrients from wastewater (both urban and industrial). Specifically, in the case of CARTIF, we are working on a technology for N and P recovery through the cultivation of microalgae and on another technology in which nutrients are recovered through bioelectrochemical processes, i.e. Microbial Fuel Cells (MFCs).
But if you like, we´ll leave that topic for another future blog post ?
In the end, I coukd not resist…I went to see AVATAR 2. Even in 3D! The idea of recalling the sensations I experienced 13 years ago as a spectator of one of the greatest technological advances in animation of the 21st century, won over the laziness of being inside a cinema for a whopping three hours. However, this time I wanted to see how something that already caught my attention in the first film of the saga had evolved: being able to establish a direct link with nature. Amazing!
Having seen the “movie” and coming back to reality, I believe that we have never lost our link with nature but have ignored it thinking that it was no longer necessary for us and that only technological advances would make this world a better place, disregarding our natural essence. It is important to know that any measure developed to protect an ecosystem, and the biodiversity that inhabits it, will protect us as part of that biodiversity and will only improve our living conditions.
Source: Raúl Sánchez Francés
Currently there is a growing need to get in touch with nature, either due to being fed up with a sedentary and overly urban life, to practice sports or to come into contact with nature and the trees that inhabit it, but without knowing the multiple benefits that his “forest or nature bath” is providing. Although it is believed that the concept of forest bathing (Shinrin-yoku in Japanese) seems to have an ancient origin, it was not until the early 1980s when the Japanese forest authorities promoted the concept to bring people closer to the benefits of the forest. The feeling of well-being that we perceive walking through the forest has a proven scientific explanation. Already in the middle of the 20th century it was shown that certain conifers were capable of purifying/disinfecting their environment by generating a natural antibiotic (phytoncides), mainly in response to the attack they continually receive from fungi. This has a a direct consequence that the presence of trees in residential areas improves the health of its inhabitants.
Source: Raúl Sánchez Francés
There is clear evidence about the essential role that green and blue spaces play in promoting a healthier and more sustainable lifestyle. In urban and peri-urban areas, natural spaces reduce exposure to potentially harmful factors such as excessive heat, noise, and air pollution. Studies have shown that green areas surrounding urban spaces are associated with lower mortality.
Similarly, various experimental and observational studies have shown that exposure to nature is associated with improvements in cognition, brain activity, blood pressure, sleep, physical activity and mental health. Special relevance is given to the improvement of mental health (anxiety, depression and stress) due to activity in nature. An increase in well-designed, equitably distributed adn accesible green/blue spaces, as promoted by the concept of Nature-Based Solutions (NBS), is an important factor in preserving and improving mental health and well-being. The COVID-19 pandemic and the subsequent economic recession have affected the mental health of the population, with an increase un symptoms of anxiety and depressive disorders, and have highlighted the need to improve our understanding of the specific types and characteristics of nature that are key to mental health.
At CARTIF, we have been working for some time on the re-naturalization of our cities, environments and all those inhabited spaces that have lost their natural quality, with the purpose of making our cities more livable…but in a natural way and in coexsitence with nature. Projects like Urban GreenUP, MyBuildingisGreen, NATMED…are a sample of this.
Taking all this into account, the medical prescription of forest bathing, of solutions based on nature or what we have called therapies based on nature (Nature based Therapies) is getting closer.
I recently had the opportunity to talk to Odile Rodríguez de la Fuente, Félix Rodríguez de la Fuente´s daughter, about the bond with nature that her father instilled in her and her sisters and that she still maintains, from her facet as a disseminator of nature, which she performs in a fantastic way. It was undoubtely Félix who perceived the disconnect between human beings and nature at a key moment in the country´s growth, which made his work even more difficult but which has allowed him to leave a deeper and more lasting mark, laying the foundations for the sought-after link with nature.
It is about looking for real and deep connections between the human being and the natural world, which go beyond cultural work in the field or some gardening experiences such as the erroneous perception that tomato plants slowly fatten when being caressed… as if it was a test of love. Nothing could be further from the truth. When you caress a tomato plant every day, its vertical growth slows down and its stem thickens, but it is nothing more than a natural reaction to a fictitious load from the wind.
However, we still have time to protect the nature that surrounds us, to bring nature closer to our cities and living spaces, and to reconnect, to link ourselves with nature.
