BIochemical impact of agricultural, Breeding and agrofood EfflueNts On concrete structures in biogas systeMs (anaerobic co-digestion) – BIBENdOM

The research programme is organized in 4 themes. The study combines experimental (laboratory and on-situ tests on an equipped biogas platform) and modelling work on microorganism-cement material interactions.
The first theme concerns the analytical characterization of real media of the biogas production in several situations and for systems using various types of agricultural effluents. The work aims to identify critical chemical conditions toward concrete and to define model media which are further used in laboratory testing.
The second theme investigates the mechanisms and kinetics of biodeterioration of cementitious materials both in laboratory conditions and on site, using an equipped platform implemented at Belesta in an agricultural biogas plant (Haute-Garonne, France). For lab testing, experimental pilots are developed to work in controlled and conditions. Long term on site testing are used to validate phenomena observed in lab and to evaluate kinetics in real conditions.
The third theme is dedicated to modelling of the biodeterioration of concrete in biogas environment. From the results of theme 2, a coupled modelling is implemented, comprising (i) the simulation of the biofilm activity at the surface of concrete and (ii) the reactive transfer modelling of microbial metabolites in the cementitious matrix. The aim is to complete the understanding of interactions mechanisms as well as developing a numerical tool for the prediction of concrete lifespan.
The fourth theme concerns the development and assessment of innovative, health- and environmental-friendly solutions to improve the durability of concrete in biogas systems. Various promising avenues, from material science (chemical resistance and biological resistance) and from biological science (positive biofilms) are explored. Optimized slag-based and/or CAC-based materials are more specifically studied on the basis of their good performances in agricultural and biological environments.

- Analysis of the mechanisms of interactions between cementitious materials and biowaste in the liquid phase in laboratory. Two types of biowaste (manure and maize substrates), with different levels of aggressiveness for the cement matrix during their anaerobic fermentation, were considered. The dynamics of biowaste composition during several digestion cycles were characterized by considering the compounds that are aggressive for the cementitious material (acids, ammonium, CO2). The impact of the chemical and mineralogical nature of the cementitious binder on the fermentation reactions and the efficiency of biogas production was analysed. Original results were obtained.
- Exposure of samples of innovative cementitious materials formulated from a wide range of binders to real environments in a semi-industrial scale digester. The materials are exposed in the gas and in the liquid phases. The first series of samples, exposed for 6 months, have been taken and are currently analysed. This work also aims to test solutions of chemical surface treatments to improve the performance of common binders.
The thermodynamic and kinetic modelling of the attack of cementitious materials in the biowaste environment is also being developed (combined attack of several metabolites: acids, CO2, ammonium, etc., with various aggressiveness, concentrations and attack mechanisms). The strategy couples reactive transport in the material (in particular by upgrading the thermodynamic databases and enriching the understanding of reaction phenomenologies based on laboratory experiments) and microbial reactivity on the surface of the material.

Further steps of the work will concern the further development of the coupled themodynamic model, the exploitation of the long-term exposure data of the samples exposed in situ, and the cross-referencing of the work of the different partners by material-dependent analysis of the biofilm structures of the materials exposed in situ.

Voegel, C., Giroudon, M., Bertron, A., Patapy, C., Matthieu, P.L., Verdier, T., Erable, B. (2019) Cementitious materials in biogas systems: Biodeterioration mechanisms and kinetics in CEM I and CAC based materials. Cement and Concrete Research 124, 105815.
M. Giroudon, M. Peyre Lavigne, C. Patapy and A. Bertron (2018) Biodeterioration mechanisms and kinetics of SCM and aluminate based cements and AAM in the liquid phase of an anaerobic digestion system. RILEM 253-MCI Conference, Microorganisms-Cementitious Materials Interactions, Toulouse, RILEM PRO 123, Vol. 1, pp. 231-240
C. Perez, C. Lors and B. Erable (2018) The specific role of microbial biofilms in the deterioration of concrete tanks for anaerobic digestion plants.RILEM 253-MCI Conference, Microorganisms-Cementitious Materials Interactions, Toulouse, RILEM PRO 123, Vol. 2, pp. 565-566
M. Giroudon, M. Peyre Lavigne, C. Patapy and A. Bertron (2018) Biodeterioration mechanisms and kinetics of SCM and aluminate based cements and AAM in the liquid phase of an anaerobic digestion.ICCRRRR 2018, Cape Town. 8 p. Keynote paper
M Giroudon, C Voegel, C. Patapy, M Peyre Lavigne, B Erable, A Bertron (2019) Performances and alteration mechanisms of OPC and of CAC-based matrices in anaerobic digestion systems, 15th Congress of the Chemistry of Cement. Prague, 11 p.
C Roosz, M Giroudon, L Lacarrière, M Peyre-Lavigne, A Bertron (2020) Contribution of thermodynamic modeling to the understanding of interactions between hydrated cement pastes and organic acids. 3RD RILEM Spring Convention 2020, Guimarães, 11 p.
M. Giroudon, M. Peyre Lavigne, C. Patapy et A. Bertron (2020) Biodeterioration mechanisms and durability of SCM based cements and AAM in anaerobic digestion systems. ICCM 2020, Toulouse, 21p.
C. Perez, C. Lors and B. Erable (2020) Implication of Biofilm on the Biodeterioration of Cementitious Materials under Anaerobic Digestion Conditions, DBMC conference, Barcelona

The anaerobic digestion process allows the treatment and the recycling of agricultural, agro-industrial and household organic wastes, into biogas (methane, etc.) used as green energy to produce heat and electricity by cogeneration technology. European policy currently supports financially the development of biogas systems to ensure energy transition towards greener energy systems, which has made the biogas sector a potentially attractive organic-waste recovery industry. In the dynamic market of biogas, concrete established itself as a suitable construction material owing to its economic interest, its airtightness properties and its high thermal inertia.
However, in contact with biowaste, concrete structures are subjected to deteriorations at every stage of biogas production because of both the chemical compounds excreted by microorganisms and the biological compounds themselves which form biofilms at the concrete surface and may create very chemically aggressive local conditions. The impact of these deteriorations on biogas plants are both economic (loss of productivity, reparation costs, etc.) and environmental (leaks of polluting effluents to the environment). In a context of significant expansion of the biogas industry, the sustainable development of the sector requires a better understanding of concrete biodeterioration in order to improve the structures’ durability in these environments.
The final aim of the BIBENdOM project is to propose efficient, health- and environment-friendly solutions for increasing the durability of concrete in biogas plants. To this end, the study will have to provide a detailed understanding of the biodeterioration phenomena. An indispensable step will be to develop biological tests aiming to rationally investigate the phenomenology of biofilm-cementitious material interactions. Finally, for the further development of a new tool to predict the service life of concrete, the bio-geo-chemical interactions between microorganisms and cement matrices will be modelled.
The operating research programme, scheduled over 42 months, will be organized in 4 themes. Two main situations of the biogas production process will be studied: (i) anaerobic transformations in the digester and (ii) the aerobic composting of the digestate. The first theme will concern the characterization of real biowastes in several situations and for various types of agricultural effluents with the view to identify critical conditions for concrete. The second theme will be focused on the investigation of the mechanisms and kinetics of biodeterioration of cementitious materials both in laboratory and in situ, notably using an equipped platform in a biogas plant. For laboratory testing, experimental pilots will be developed in order to work in controlled conditions. The third theme will be dedicated to modelling of the biodeterioration of concrete in biogas environments. A coupled modelling (i) of the biofilm activity at the concrete surface and (ii) of the reactive transfer of microbial metabolites in the cementitious matrix will be implemented. The random growth and activity of the biofilm at the surface will be modelled using a probabilistic approach. The fourth theme will concern the development and assessment of solutions to improve the durability of concrete in biogas systems. Various promising avenues, from material science (chemical and biological resistance) and from biological science (positive biofilms) will be explored.
This project is strongly multidisciplinary and requires skills related to microbiology, material science, process engineering, biological and biochemical engineering, biofilm microscopy, etc. Four laboratories: LMDC, project coordinator, LGC, LISBP, and ARMINES-ENSM Douai, and two companies: Ecocem France, producer of GGBS (ground granulated blast furnace slag), and Cousté Solutions, a SME specialized in the production of concrete tanks for biogas plants, will be involved in the project.