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Projecte llegit

Títol: Operation of a submerged modular Microbial Electrolysis Cell (MEC) for ammonium recovery and emission mitigation in slurry storage tanks

Estudiant que ha llegit aquest projecte:

Tutor/a o Cotutor/a: CERRILLO MORENO, MÍRIAM

Departament: DEAB

Títol: Operation of a submerged modular Microbial Electrolysis Cell (MEC) for ammonium recovery and emission mitigation in slurry storage tanks

Data inici oferta: 16-01-2024      Data finalització oferta: 16-03-2024

Estudis d'assignació del projecte:
    GR ENG SIS BIOLÒG 23

Lloc de realització:


En empresa (cal signar un conveni de cooperació)

        Tutor/a Extern: August Bonmatí Blasi
        Institució/Empresa: IRTA

Paraules clau:
Bioelectrochemical systems, Ammonium, Slurries, Emissions to the atmosphere, Microbial Electrolysis Cell, Cation-Exchange Membrane, Emission Rate, Greenhouse Gases, Coulombic Efficiency, IRTA

Descripció del contingut i pla d'activitats:
The outdoor storage of slurry generated on farms in ponds presents a major problem in terms of emissions of greenhouse gases and ammonia into the atmosphere. In recent years, techniques are being developed with the aim of reducing these emissions into the atmosphere, such as the covering of ponds or the acidification of slurry. As an alternative, this study proposes the application of bioelectrochemical systems to slurry storage ponds, given that they have been widely studied for the recovery of ammonium from residual effluents.

The objective of the present work is the operation of a new modular configuration of Microbial Electrolysis Cell (MEC), which can be submerged in a slurry pond in order to recover ammonium. The potential effect of the extraction and recovery of ammonium by the MEC on emissions to the atmosphere from the storage of slurry in ponds will be studied.

The methodology that will be used will be the carrying out of tests in tanks of 1 m3 of slurry, comparing a control tank with a tank with a submerged MEC module. Equipment will be used to measure emissions in the atmosphere (laser/photoacoustic).

The following tasks will be performed:
1. Literature review on the application of MECs to ammonium recovery and submerged MEC configuration.
2. Design of the monitoring plan for the tests of the modular submerged MEC.
3. Installation of the submerged MEC system.
4. Operation of the modular MEC reactor, preparation of feed solutions, maintenance, data collection and periodic sampling of emissions and reactor effluents, following the designed plan.
5. Elaboration of the data obtained for the determination of the efficiencies of ammonium removal and emission reduction.
6. Elaboration of conclusions and guidance on the improvement in the design of the submerged MEC.

This work will be carried out within the framework of the GEMBESH project, in which the external tutors participate as researchers, and the student will be integrated into the project team.

Overview (resum en anglès): Slurry management on pig farms, especially fattening pigs, is a critical environmental concern due to ammonia (NH3) and greenhouse gas (GHG) emissions. This project proposes the design, construction and operation of a submerged Microbial Electrolysis Cell (sub-MEC) system for the recovery of ammonium (NH4+) and the reduction of emissions in slurry storage tanks, improving agricultural sustainability.

Experiments began in the laboratory and progressed to a pilot scale. The methodology includes two experimental setups: in the laboratory, two 40 L methacrylate tanks (one with MEC and the other as a control) were used to replicate ideal conditions for ammonium recovery, biogas production and emission control . At pilot scale, two 1 m3 IBC tanks were used under real environmental conditions. The MEC includes a cation exchange membrane that separates the cathode from the anode. In the laboratory, a potentiostat was used to supply power and monitor the voltage and current, while a direct current (DC) power supply was used on the pilot scale. A Lindvall hood was used to measure NH3 and GHG emissions, and analytical methods were applied to monitor the system.

The results show that the sub-MEC efficiently recovers ammonium and reduces gas emissions. In the laboratory experiment, 6.44% nitrogen (N) was recovered over two periods. The first period showed higher N recovery with an average current density of 0.19 A/m2, a nitrogen transfer rate of 0.82 gN/m2/day and a Coulombic efficiency of 6.04%. The concentration of NH3 in the tank with MEC was lower than in the control tank, suggesting that a large long-term reduction in NH3 emissions could be achieved. The production of methane (CH4) in the biogas was 16.30% in the first period, increasing to 27.96% in the second. At pilot scale, the MEC system recovered 61.43 gN in 117 days. Regarding NH3 emissions, the MEC tank showed a slightly lower emission rate (ER) (0.15 mg/m2/s) compared to the control tank (0.16 mg/m2/ s). The system's effectiveness in reducing NH3 was demonstrated under controlled conditions, suggesting that the MEC could achieve similar reductions in real environments with longer observation periods. CH4 ER in the MEC tank were lower (0.09 mg/m2/s) than in the control tank (0.15 mg/m2/s). CO2 emissions were slightly higher in the MEC tank, with a ER of 0.13 mg/m2/s compared to 0.10 mg/m2/s in the control. N2O ER were undetectable in both tanks.

Overall, the MEC technology is promising for the sustainable management of pig slurry. With continued research and improvement, the sub-MEC system has the potential to improve NH4+ recovery, biogas production and emissions control under real-world conditions.

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