Efficient Aeration Technology

The performance of air or oxygen injection systems in activated sludge tanks determines in great part the energy consumption and the treatment efficiency of whole wastewater treatment plants. Experts in our team work closely with industrial partners, municipal plant operators and other research institutions in the study and optimization of aeration systems. The advanced measuring instruments and test facilities of HZDR are available to conduct analyses of aeration systems in terms of:

• Oxygen transfer rate and efficiency according to DWA-M 209 guidelines
• Gas bubble size and distribution
• Mixing efficiency
• Contaminant removal (NH3-N, NO3-N, BOD5, COD)

The infrastructure within the flow laboratory of CLEWATEC (https://www.clewatec.de/) and HZDR includes several test stands as well as a wastewater laboratory certified to biosafety level 2 for analyses with real activated sludge. Optical measurement techniques like videometry, flow microscopy and image processing algorithms are available together with standard devices for the analysis of carbon removal, nitrification and denitrification processes.

Two DN 900 columns with a maximum filling height of 4 metres are installed in our wastewater laboratory and equipped with instruments for oxygen transfer and nitrification experiments. The two identical columns enable parallel experiments at depths similar to those in real activated sludge tanks. The infrastructure of the flow laboratory is supplemented by the 14 cubic metre mobile activated sludge tanks, which can be used as a bypass in real wastewater treatment plants. Like the DN 900 columns, the two identical tanks are suitable for parallel performance tests with maximum comparability.

Undeveloped optimization potential of existing systems is revealed through these analyses, allowing our partners to reduce operational costs, minimize environmental impacts, and gain major competitive advantages. The funded project MILA is centred on this research theme.

Publications:

• Mohseni, E., Reinecke, S. F., Hampel, U., Controlled bubble formation from an orifice through harmonic gas pressure modulation. Chemical Engineering Journal, 470, 143953 (2023).
• Mohseni, E., Eduarda Chiamulera, M., Reinecke, S. F., Hampel, U., Bubble formation from sub-millimeter orifices: Experimental analysis and modeling. Chemical Engineering and Processing – Process Intensification, 173, 108809 (2022).
• Herrmann-Heber, R., Ristau, F., Mohseni, E., Reinecke, S. F., Hampel, U., Experimental Oxygen Mass Transfer Study of Micro-Perforated Diffusers. Energies, 14 (21), 7268 (2021).
• Mohseni, E., Bauermann Lang, G., Reinecke, S., Hampel, U., A Mechanistic Model for Bubble Formation from Microscale Orifices under Constant Gas Flow Conditions. ACS Eng. Au, 13 July 2021.
• Mohseni, E., Ziegenhein, T., Reinecke, S., Hampel, U., Bubble formation from sub-millimeter orifices under variable gas flow conditions. Chemical Engineering Science, 116698 (2021).
• Mohseni, E., Kalayathine, J. J. , Reinecke, S., Hampel, U., Dynamics of bubble formation at micro-orifices under constant gas flow conditions. International Journal of Multiphase Flow, 132, 103407 (2020).
• Skouteris, G., Rodriguez-Garcia, G., Reinecke, S. F., Hampel, U., The use of pure oxygen for aeration in aerobic wastewater treatment: A review of its potential and limitations. Bioresource Technology, 312, 123595 (2020).
• Höhne, T., Mamedov, T., CFD Simulation of Aeration and Mixing Processes in a Full-Scale Oxidation Ditch. Energies, 13 (7), 1633 (2020).
• Mohseni, E., Herrmann-Heber, R., Reinecke, S. F., & Hampel, U., Bubble generation by micro-orifices with application on activated sludge wastewater treatment. Chemical Engineering and Processing – Process Intensification, 143, 107511 (2019).
• Herrmann-Heber, R., Reinecke, S. F., Hampel, U., Dynamic aeration for improved oxygen mass transfer in the wastewater treatment process. Chemical Engineering Journal, 386, 122068 (2019).
• Reinecke, S. F., Höffmann, A. K., Hampel, U., Ehrhard, P., Stachowske, M., „Leistungsoptimierung von Kläranlagen durch gezielte Strömungsführung in Belebtschlammbecken – LEOBEL“, Schlussbericht, DBU AZ30799 (2018).
• Herrman-Heber, R., Kutschke, S., Reinecke, S. F., Hampel, U., „Steigerung der Energieeffizient bei der biologischen Abwasserreinigung durch den Einsatz von Kanülenbegasern mit dem Ziel eines nachhaltigen Gewässer- und Klimaschutzes – SEBAK”, Schlussbericht, MKULNV 17-04.02.01-9a/2014 (2018).
• Mohseni, E., Herrmann-Heber, R., Reinecke, S. F., & Hampel, U., Bubble Generation by Solid Membrane Spargers for Activated Sludge Wastewater Treatment Application. Proceedings of 9th Eastern European Young Water Professionals Conference IWA YWP, 24.-27. May 2017, Budapest, Ungarn (2017).