Ecoval Sudoe project successfully achieves the production of volatile fatty acids from sludge and urban biowaste

The capacity of organic waste of urban origin to increase microbiological diversity in agricultural and forestry soils has also been demonstrated.

The Ecoval Sudoe project, co-financed by the Interreg Sudoe Programme through the European Regional Development Fund (ERDF), has successfully come to an end. This project, which started in November 2020, has successfully scaled up the technology to produce high-purity volatile fatty acids from sewage sludge and municipal biowaste. The initiative has demonstrated that both organic wastes have enormous potential for biofactory development and can be used as renewable and sustainable feedstock in the chemical industry.

Thanks to European funding of around 1.5 million euros and the work of the consortium, not only the technology was improved but the project also achieved the development of business models and the identification of legal barriers to its implementation. In addition, it has been demonstrated that the model can be replicated in industrial environments, which opens the door to its implementation in different sectors such as canning or dairy. 

The results of the Ecoval project (Coordination strategies for the management and valorisation of sludge and organic waste in the SUDOE region) have also highlighted the capacity to use organic waste of urban origin (biostabilised waste and sewage sludge) to increase microbiological diversity in agricultural and forestry soils. 

Thanks to this initiative, led by Cetaqua and with the participation of a consortium formed by the University of Santiago de Compostela, the Natural Heritage Foundation of Castilla y León, the Galician Business-University Foundation, INSA Toulouse, Nereus, Porto Ambiente and Aguas do Tejo Atlántico, great progress has been made in the sustainable production of materials and chemical products from organic waste, thus contributing to the circular economy and the protection of the environment.

Resources and environmental awareness 

Beyond the results at a technical level, the consortium has placed great emphasis on environmental education and awareness since the correct separation of waste is extremely important for projects such as Ecoval Sudoe. 

Around 1,500 pupils of different ages participated in activities set up by the consortium with the aim of raising awareness of the correct separation of waste at source, with a special focus on the fifth container for the separation of the organic fraction and on waste that should not be flushed down the toilet. One of the communication campaigns carried out by the project was awarded the European Waste Reduction Week Special European Award in recognition of its impact, creativity, and participatory nature. 

The project’s website also contains other materials such as videos and posters or a good practice guide, which allow visitors to solve their doubts about correct waste separation, as well as interactive games to test the knowledge acquired. All these tools are essential for scaling up business models such as the one proposed by Ecoval, since without correct waste separation, no innovative process for waste recovery can be carried out.

Optimisation, evaluation and development: INSA Toulousse’s contributions to ECOVAL

With more than 17,000 engineers working in all economic sectors, the National Institute of Applied Sciences of Toulouse (INSA Toulouse), a public scientific, cultural and professional institution under the authority of the French Ministry of Higher Education, was created in 1963 and is recognised for the excellence of its training and its students. Its participation in the Sudoe ECOVAL project focuses on three actions: the optimisation of volatile fatty acid production in bioreactors, the evaluation of the methanogenic potential of acidogenesis digestates and the development of a model of the global urban biowaste management system.

 

Optimisation of volatile fatty acid production in bioreactors

In collaboration with CETAQUA, INSA Toulouse is working to optimise the production of Volatile Fatty Acids (VFA) from biowaste. This production is carried out in a bioreactor that performs acidogenesis. The VFA are then extracted and purified for commercial use. INSA Toulouse uses a dynamic simulation model of the acidogenesis process to describe the evolution of substrates and reaction products according to the operating parameters of the process. This tool makes it possible to choose the operating conditions that lead to the most significant production of VFAs and the most favourable for commercialisation. A collaboration with the company Nereus led to the integration of VFA recovery constraints into the criteria for optimising VFA production.

The progress achieved allows the variability of bio-waste and inhibitions of certain biological processes to be taken into account in order to better predict the quantities and qualities of the products formed.

 

Assessment of the methanogenic potential of digestates from acidogenesis

After the production of VFA, a material residue remains that can be recovered by methanisation. INSA Toulouse is evaluating methane production on this residue. It is developing an original continuous process that increases methane production and thus bio-waste recovery. This process is based on a coupling between mesophilic digestion of the waste coupled with thermophilic digestion of the digestate. The progress achieved makes it possible to reduce the quantity of sludge to be disposed of thanks to a more thorough degradation of the mixed sludge. We will see this autumn whether these results can be reproduced on acidified sludge waste and then on biowaste.

 

The development of a model of a global municipal biowaste management system

The global modelling tool allows the assessment of bio-waste management channels at the city level. The objective is to quantify the production of bio-waste in an urban territory and to optimise its collection, transport, treatment, and valorisation into volatile fatty acids and methane. The modelling is developed using data and scenarios from three cities: Toulouse (France), Porto (Portugal) and Palencia (Spain); with different sizes, urban planning, and collection strategies. Toulouse and Palencia are committed to the collection at voluntary drop-off points (VDPs) and composting, while Porto already has a door-to-door collection.

The three case studies are used to compare various treatment solutions: composting and/or anaerobic digestion by 2030 or VFA production. The comparison is made on the basis of flow and energy balances. The cooperation with another partner (Biogroup CRETUS USC) also allows comparison on the basis of the environmental impacts of bio-waste management channels. The model is already developed and simulations of the first scenarios are being carried out.

Ultimately, this modelling tool and the resulting results will help communities and companies to make decisions on the most virtuous management methods from the point of view of environmental impact and economic profitability. It will also allow the identification of priority areas in the sector to be optimised.

Schematic of the MAD-TAR pilot of the ECOVAL project installed at INSA in Toulouse, France.

CETAQUA showcases ECOVAL’s advances in sustainable waste management at CORFU

CETAQUA showcases ECOVAL's advances at CORFU

The International Conference on Sustainable Solid Waste Management (also called CORFU 2022) took place on the Greek island of Corfu from 15-18 June. This year, in its ninth edition, it sought to address the important issue of sustainable solid waste management by promoting safe practices and effective technologies. It aimed to stimulate the interest of scientists and citizens and inform them about the latest developments in the field of municipal solid waste management. The exhibitions were located in the Municipal Theatre in the city center, but could also be viewed online, subject to prior registration and booking.

 

The topics discussed were closely related to the ECOVAL project and its innovations. Therefore, on Thursday 16th at 18:00hrs, Ánder Castro, researcher at CETAQUA, presented the results obtained through experimentation in the pilot WWTP of Ourense. The paper is entitled “Thermal hydrolysis pre-treatment has no positive influence on VFA production from sewage sludge” and is the result of the research carried out by Ánder himself together with S. Balboa, V. Paramá, B. Álvarez, C. Castro-Barros, J.M. Lema and A. Taboada-Santos. It is part of session XV of the event, in room 3, dedicated to the waste valorisation.

 

More specifically, the talk dealt with the effect of sewage sludge pre-treatments (in particular the so-called thermal hydrolysis) on the production of volatile fatty acids. This knowledge is very useful to reinforce the overall objective of the conference: to go a step further in solid waste management, for which it helps a lot to learn how to achieve value-added products by applying biorefinery processes to them.

 

The conference was a great opportunity to brought together scientists and professionals from government departments, industry, municipalities, universities, private companies and research centres, providing a forum for the exchange of the latest ideas and techniques in the world of waste management.

Turning mud into gold

This is what the NEREUS network is working on within the ECOVAL project. Ecoval Sudoe is developing a method for the extraction of high added value molecules, Volatile Fatty Acids (VFAs), from processed sludge. The aim of the NEREUS project is to test a process for the extraction and purification of VFAs from sludge sent to them by the coordinator CETAQUA. This process must be economically viable and meet market specifications. In addition to this double constraint, there are legal barriers related to the recovery of bio-waste and sludge from wastewater treatment plants. This is why the Ecoval Sudoe project tries to go beyond what is established.

 

Extracting, sanitising, filtering and concentrating
NEREUS has developed a dynamic nanofiltration pilot plant with three major advantages: it extracts the molecules of interest from organic sludge, ensures their sanitisation and filters at low energy costs. After this first filtration stage, concentration processes are applied to achieve the desired objective.

Waste organic matter is further valorised at INSA Toulouse for energy production and through the land application study at the Fundación Patrimonio Natural de Castilla y León.

ECOVAL Sudoe with World Water Day

World Water Day is held on 22nd March. In 2022, the spotlight is on groundwater: those that feed, apart from rivers and springs, wells and pumps. Life would not be possible without it. Most arid areas of the planet depend on this resource entirely, which supplies a large proportion of the water we use for consumption, sanitation, food production and industrial processes

Almost all fresh water in liquid form in the world is groundwater. In much of the globe, these reserves are being overexploited and we run the risk of weakening this resource. Moreover, as climate change worsens, groundwater is becoming increasingly critical, making it more necessary than ever to manage it sustainably, as well as reuse and give a second life to the other water sources that we have. The UN has just published its annual report on the state of water to mark the occasion of this day, and you can check it out here.

ECOVAL joins this celebration, which aims to raise awareness about the global water crisis and the need to seek measures to address it so that we can achieve Sustainable Development Goal No. 6: Clean water and sanitation for all by 2030. To get closer to that forecast, we cannot forget about wastewater and its management.

 

1 million, 300 thousand tonnes of sludge not reused

Urban wastewater treatment processes generate large amounts of sludge. In Galicia alone, over 150 thousand tonnes of this sludge are generated each year, which would fill the inside of the Santiago de Compostela Cathedral every year. If we were to talk about the figure in the Sudoe space, it would rise to 1 million, 300 thousand tonnes.

This sludge has traditionally been seen as waste, but in the Ecoval Sudoe project we demonstrate the technical feasibility of its transformation into high value-added products such as Volatile Fatty Acids, which are transformed into adhesives, lubricants or paints in the chemical and petrochemical industry or fertilisers. A profound transformation in the management of the water cycle based on the circular economy and sustainability. The Ourense Biofactory thus allows us to go beyond the traditional concept of water purification to transform sludge into new valuable resources and guarantee a second life for it. You can learn more about the function of ECOVAL in wastewater recovery, which allows the cycle of this key resource to be extended for life, in the following video:

To follow the conversation about World Water Day 2022 online, you can use the hashtag #WorldWaterDay or check out the UN account dedicated to it.