ECOVAL consortium meets in Toulouse

 

The National Institute of Applied Sciences of Toulouse (INSA Toulouse) hosted the consortium meeting of the Ecoval Sudoe project in the same French city on Wednesday and Thursday (23 and 24 November, respectively) in order to share and present the progress achieved so far, as well as the next steps to be taken.

 

The kick-off was at nine o’clock in the morning, where CETAQUA made an introduction and presentation of the project, as well as its contribution to it from a biotechnological perspective to valorise organic waste. Subsequently, the rest of the actors (FEUGA, INSA TBI, NEREUS, USC BioGroup, ADTA, FPNCyL and Porto Ambiente) presented their different contributions to Ecoval Sudoe until midday, when there was a break to resume the activity in the afternoon.

 

On Thursday, the consortium visited the Ginestous Wastewater Treatment Plant (WWTP) in Toulouse to observe first-hand how the city’s sewage sludge is currently treated. It also analysed its potential for transformation into a biofactory, as pursued by the Ecoval Sudoe model to promote a more sustainable and circular economy.

 

This consortium meeting is the fifth one held by the project, after the last one organised last June in the city of Porto, hosted by Porto Ambiente. In this type of events, synergies are generated between the different agents and are a key element for the proper functioning of all types of projects, even more so in the case of Ecoval Sudoe due to the multiplicity of actors, interests and challenges faced with the aim of promoting a circular and sustainable business model in a context of green transition.

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.

Hands in the mud! Ecoval Sudoe completes work on pilot plant for the production of volatile fatty acids

One of the objectives of the Ecoval Sudoe project is to demonstrate the technical feasibility of producing volatile fatty acids (VFA) from urban sludge. To do this, at the Ourense Wastewater Treatment Plant (WWTP), Cetaqua has set up different tests to optimise the generation of acids such as acetic, propionic, or butyric acid from sewage sludge.

In order to determine the most suitable operating conditions for the pilot VFA production plant, different laboratory-scale tests were first carried out, such as batch tests on a 0.5L scale and the operation of semi-continuous reactors of 5L volume, which demonstrated the suitability of sewage sludge as a substrate with high potential for the production of high added value bioproducts with VFA.

The information provided at the laboratory scale has helped Cetaqua technicians to have a first approximation of the VFA production yields that can be obtained from sludge with and without pre-treatment. They were also able to analyse the effect of operating parameters such as pH, feed/microorganism ratio, hydraulic residence time, etc.

On a pilot scale, the technicians have optimised the fermentation process for the production of VFA, obtaining a stream that has to undergo solid-liquid separation, a unitary operation that has had to be perfected thanks to “jar tests” that have made it possible to determine the optimum doses of coagulant and flocculant for the division of the solid and liquid fractions. Thus, the objective of producing a liquid current rich in VFA for the partner NEREUS to study its clarification and concentration and a high-dryness solid cake that INSA will recover energetically has been achieved.

Following these tests, work is now continuing on the pilot plant which, after a start-up phase marked by hydraulic difficulties in operation and the necessary adjustments, is now operating more robustly. It will soon begin to be fed with biowaste.

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