Group of Environmental Biotechnology

Universidade de Santiago de Compostela

Universidade de Santiago de Compostela Campus Vida Cretus

Group of Environmental Biotechnology

Universidade de Santiago de Compostela

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1.3.2 Integrated anaerobic codigestion /postreatment

There are a lot of wastes from agriculture, forestry, different types of food industries, or residues from animals that lead to the accumulation of organic wastes in soils and waters, causing serious environmental problems, such as soil contamination by heavy metals, air emissions of greenhouse gases (GHG) and increasing pathogen concentrations in groundwater. This research line focuses on the study of the anaerobic (co-) digestion of organic solid wastes, especially agro-industrial wastes (manure, fish wastes, biodiesel residues, silage and animal feed remains, bioethanol residues, molasses, etc..), and is subdivided into 3 actions: definition of optimal mixtures and operational treatment conditions, study of the diversity and functionality of the microbial population and monitoring and control of anaerobic (co-) digesters.

Definition of optimal mixtures and operational treatment conditions This action focuses on determining the physical-chemical characteristics and the methanogenic potential of each waste as well as of several mixtures of them to define the optimal mixtures and operational treatment conditions. These optimal treatment conditions will be defined not only form maximizing biogas production, but also for obtaining a digestate of adequate quality for subsequent use as fertilizer. The experiments are carried out both at laboratory and pilot scale in different types of reactors (UASB, CSTR) according to the characteristics of the waste to be treated.

Studying the diversity and functionality of the microbial population Anaerobic (co-) digesters are characterized by complex microbial consortia, formed by groups of bacteria responsible for the early stages of the process (hydrolysis, acidogenesis and acetogenesis) and groups of archaea responsible for the final step of methane production (methanogenesis). Until recently, these processes behave as a "black box", but the development of culture-independent molecular techniques such as denaturing gradient gel electrophoresis (DGGE) technique and fluorescence in situ hybridization (FISH) have demonstrated that the microbial community characteristics ("Who is there doing what with whom") may also play an important role for a good digester performance and could lead to an early detection of operational problems, enabling preventive actions. Thus, the objective of this line is to investigate microbial population characteristics and dynamics, combining the knowledge gained with conventional measurements.

Monitoring and control of anaerobic (co-) digesters Nowadays, there are no appropriate control systems for the proper operation of anaerobic (co-) digesters, either because they are not widely used as they were developed for a specific application or because they require a too complex monitoring system at an unacceptable cost. This line will develop a dynamic model of the process, based on that developed by IWA (Anaerobic Digestion Model 1, ADM1) and taking into account the nature of the waste to be treated (mainly solid waste), to forecast the system behaviour. This model is implemented in a "virtual plant" and will be calibrated and validated with experimental data. From this model, control strategies will be developed to maximize biogas production without compromising process stability


· Novel biorefinery platform methodology for a driven production of chemicals from low-grade biomass (BIOCHEM)
PCIN-2016-102, ERA-IB-2 7th call, ERA-IB-16-052 / European Commission. (01.11.2016 - 31.10.2019)

· Potential of Innovative Technologies to Improve Sustainability of Sewage Treatment Plants (Pioneer_STP) feder_color_2_0.pngwaterjpi.png
MINECO (PCIN-2015-22) / European Commission_WaterJPI (ID199). (01.05.2016 - 30.04.2019)

Completed Projects

European pigs and cows jointly produce about 1.27 billion tonnes of manure per year, a largely unexploited resource of organic carbon and nutrients, and therefore an exquisite ‘mining’ opportunity.

ManureEcoMine proposes an integrated approach to the treatment and reuse of animal husbandry waste in nitrate vulnerable and sensitive areas and beyond, by applying the eco-innovative principles of sustainability, resource recovery and energy efficiency. Technologies of proven efficacy in the wastewater treatment field will be combined in several process configurations to demonstrate their technological and environmental potential at pilot scale for cow and pig manure. Anaerobic digestion (mesophilic/thermophilic), ammonia stripping, struvite precipitation and partial nitritation/anammox will be key technologies that will be combined to demonstrate their technological and environmental potential at pilot-scale for cow and pig manure treatment.
To render the cradle-to-cradle approach complete, the fertilizer and potential trace contaminants effects of recovered nutrients on plant growth and soil health and emissions will be established, and safety will be managed. Life cycle analyses and economic viability will determine the sustainability of the concept as such, and identify the most environmentally friendly technology and most effective and safe reuse strategy. Risk management will be developed with regard to trace contaminants for guaranteeing safe handling and high product quality for a closed nutrient cycle.

More information can be found at: www.manureecomine.ugent.be.

Anaerobic co-digestion aims at treating different organic residues that can be blended for optimal energy and resources recovery. The COMDIGEST project’s main objective is to significantly improve the performance of anaerobic co-digestion processes, in terms of biogas productivity, digestate quality, process stability and environmental impacts.

The First task focuses on the development of a comprehensive model of anaerobic co-digestion, capable of describing accurately the process dynamics. In a highly innovative approach, the model will incorporate relevant information on the interrelations between microbial ecology and process performance (from Task 2).

The Second task will aim at understanding diversity, functionality and the limits of optimal performance of the microbial community. Experiments will be conducted in discontinuous and in continuous (co-substrates, controlled perturbations) in order to investigate the characteristics and dynamics of the microbial community. The knowledge acquired will be combined with physical and chemical measurements to create an early microbial indicator of destabilization of the process and to design alternatives for recovery.

The Third task will focus on the development and validation of optimal control strategies based on the model developed in Task 1. Optimization would comprise a multiobjective function, considering not only biogas production but also digestate quality and global environmental impacts. Optimal control strategies will be validated in a well instrumented anaerobic co-digestion pilot plant.

Since the objective of this project is to improve the anaerobic co-digestion processes, CoMDigest project’s results will be integrated and a guideline document will be elaborated and presented to stakeholders including relevant companies.

The project aims at the production of biofuels (hydrogen, ethanol, butanol and methane) from C6 & C5 sugars-rich substrates by anaerobic microbial communities, objectives are:
i) To develop qualitative and quantitative models to describe product formation from anaerobic natural mixed microbial ecosystems. This aims at controlling the process towards the production of gas and liquid biofuels, like hydrogen, ethanol and butanol.
ii) To evaluate the feasibility and potential for production of hydrogen and alcohols by bioelectrochemical reduction of organic acids in microbial electrolysis cell (MEC).

Cutting-oil wastewaters are residual streams from metallurgical industry and its management constitutes an environmental problem. Biogas production from these waste streams by anaerobic co-digestion can be an interesting alternative to the current management technology, incineration, as it also provides an energy recovery and reduces the risk of polluting emissions into the atmosphere.
Since these oils and lubricants can contain a high concentration of heavy metals, lipophilic substances and other toxic compounds for anaerobic microorganisms, anaerobic co-digestion with another substrate, such as livestock waste (eg. pig slurry), would be a solution to the problems this process can face. Therefore, the main objective of this project is to evaluate the anaerobic co-digestion as a treatment for cutting oil wastewaters generated in the metallurgical industry and the subsequent recovery of biogas produced.

In the first phase of this project, the physico-chemical characterization and methanogenic potential tests will be conducted with the wastes generated in the Mouriscade Farm (cow manure, silage remains and fodder remains) and with several mixtures of them for energy recovery by anaerobic co-digestion. In the second phase of the project, the anaerobic co-digestion of 3 waste mixtures selected from the results obtained in the first phase will be evaluated in a pilot plant of 30 kWe.

Consulting during the construction and installation of a pilot plant and commissioning during the start-up and operation, including the realization of the required analyses to evaluate its performance.

The unique and strategic PROBIOGAS project integrates a set of scientific and technological activities that are interrelated and have a common objective: the development of sustainable agro-industrial biogas production and use, and the demonstration of feasibility and promotion in Spain. The project includes a set of 13 actions or sub-projects: 3 technical feasibility studies, 2 applied research projects, 1 R&D project, 6 technological development projects (demonstration) and a complementary action. In PROBIOGAS, 28 partners from research institutes and companies throughout Spain are involved. The project duration is 5 years (2007-2011) and is coordinated by AINIA Technology Centre.
More information at: http://www.probiogas.es/

Biogrup has participated in 3 sub-projects:

  • Sub-project 2: Production of biogas. The objective of this sub-project is to develop and/or optimize the anaerobic co-digestion of raw agro-industrial materials strategic in Spain.
  • Sub-project 12: Control and automation of anaerobic co-digestion of pig manure and agro-industrial wastes. The objective of this sub-project is the selection or adequacy of the instrumentation for the control and automation of anaerobic co-digestion installations, and the development of diagnosis and control modules.
  • Sub-project 14: Links between microbial population and operating parameters in anaerobic digesters. The objective of this sub-project is to improve knowledge of microbial ecology of anaerobic digesters in order to correlate microscopic parameters with the macroscopic ones describing the behavior of the system.