Stirred tank reactor with dual impeller Rushton turbine for application of wastewater treatment - Process optimization and CFD simulation

Teli, Shivanand; Kulkarni, Sunil

doi:10.22104/aet.2023.6207.1710

Stirred tank reactor with dual impeller Rushton turbine for application of wastewater treatment - Process optimization and CFD simulation

Document Type : Research Paper

Authors

Chemical Engineering Department, GF’s Gharda Institute of Technology, Khed, India

10.22104/aet.2023.6207.1710

Abstract

The treatment of industrial wastewater by economical and efficient methods is being explored to improve treatment efficiency and costs. Wastewater treatment via biological methods to reduce carbonaceous matter is common in the form of an activated sludge process (ASP). In the current work, the aerobic decomposition of waste was carried out in a reactor with constant stirring with a Rushton type turbine. The optimum values of the flow rate of air were obtained for two reactor impeller configurations for better waste degradation. The extent of degradation in the stirred tank reactor was studied for different values of impeller clearances. Two configurations, C1 and C2, were investigated. It was observed that under a continuous air supply for 36 hours, the impeller configuration C2 provided 80% degradation compared to 74.4 % for C1. Increased values of superficial gas velocity (U_G) and impeller speed resulted in decreased degradation due to shear stress on microorganisms for two impeller configurations. The hydrodynamic study confirmed that the impeller configuration C1 required less power consumption than C2 for the same operating condition. The k-epsilon turbulent model and the population balance model were used in combination. The models were validated with the experimental results of the hydrodynamic parameters for the values of operating parameters over a considerable range. The forecasting of mass transfer coefficients from different models was compared with practically determined values for the two configurations of impeller positions in the tank.

Graphical Abstract

Keywords

Main Subjects

modeling and simulation

References

[1] Gogate, P. R., Pandit, A. B. (2004). A review of imperative technologies for wastewater treatment I: oxidation technologies at ambient conditions. Advances in Environmental Research, 8(3-4), 501-551.

https://doi.org/10.1016/S1093-0191(03)00032-7

[2] Pittoors, E., Guo, Y., Van Hulle, S. W. (2014). Oxygen transfer model development based on activated sludge and clean water in diffused aerated cylindrical tanks. Chemical Engineering Journal, 243, 51-59.

https://doi.org/10.1016/j.cej.2013.12.069

[3] Moussavi, G., Naddafi, K., Mesdaghinia, A., Deshusses, M. A. (2007). The removal of H₂S from process air by diffusion into activated sludge. Environmental Technology, 28(9), 987-993.

https://doi.org/10.1080/09593332808618856

[4] Nadayil, J., Mohan, D., Dileep, K., Rose, M., Parambi, R. R. P. (2015). A study on effect of aeration on domestic wastewater. International Journal of Interdisciplinary Research and Innovations, 3(2), 10-15.

[5] Fuchs, W., Binder, H., Mavrias, G., Braun, R. (2003). Anaerobic treatment of wastewater with high organic content using a stirred tank reactor coupled with a membrane filtration unit. Water Research, 37(4), 902-908.

https://doi.org/10.1016/S0043-1354(02)00246-4

[6] Walker, G. M., Weatherly, L. R. (1999). Biological activated carbon treatment of industrial wastewater in stirred tank reactors. Chemical Engineering Journal, 75(3), 201-206.

https://doi.org/10.1016/S1385-8947(99)00109-6

[7] Siddique, N. I., Munaim, M. S. A., Wahid, Z. A. (2015). Role of biogas recirculation in enhancing petrochemical wastewater treatment efficiency of continuous stirred tank reactor. Journal of Cleaner Production, 91, 229-234.

https://doi.org/10.1016/j.jclepro.2014.12.036

[8] Esteves, B. M., Rodrigues, C. S., Boaventura, R. A., Maldonado-Hódar, F. J., Madeira, L. M. (2016). Coupling of acrylic dyeing wastewater treatment by heterogeneous Fenton oxidation in a continuous stirred tank reactor with biological degradation in a sequential batch reactor. Journal of Environmental Management, 166, 193-203.

https://doi.org/10.1016/j.jenvman.2015.10.008

[9] Gargouri, B., Karray, F., Mhiri, N., Aloui, F., Sayadi, S. (2011). Application of a continuously stirred tank bioreactor (CSTR) for bioremediation of hydrocarbon-rich industrial wastewater effluents. Journal of Hazardous Materials, 189(1-2), 427-434.

https://doi.org/10.1016/j.jhazmat.2011.02.057

[10] Kanaujiya, D. K., Pakshirajan, K. (2022). Mass balance and kinetics of biodegradation of endocrine disrupting phthalates by Cellulosimicrobium funkei in a continuous stirred tank reactor system. Bioresource Technology, 344, 126172.

https://doi.org/10.1016/j.biortech.2021.126172

[11] Shen, R., Jing, Y., Feng, J., Zhao, H., Yao, Z., Yu, J., Chen, J., Chen, R. (2021) Simultaneous carbon dioxide reduction and enhancement of methane production in biogas via anaerobic digestion of cornstalk in continuous stirred–tank reactors: The influences of biochar, environmental parameters, and microorganisms. Bioresource Technology, 319, 124146.

https://doi.org/10.1016/j.biortech.2020.124146

[12] Yadav M., Vivekanand, V. (2021). Combined fungal and bacterial pretreatment of wheat and pearl millet straw for biogas production – A study from batch to continuous stirred tank reactors. Bioresource Technology, 321, 124523.

https://doi.org/10.1016/j.biortech.2020.124523

[13] Azimi, B., Abdollahzadeh–Sharghi, E., Bonakdarpour, B. (2021). Anaerobic–aerobic processes for the treatment of textile dyeing wastewater containing three commercial reactive azo dyes: Effect of number of stages and bioreactor type. Chinese Journal of Chemical Engineering, 39, 228–239.

https://doi.org/10.1016/j.cjche.2020.10.006

[14] Ayare, S.D., Gogate, P.R. (2019). Sonocatalytic treatment of phosphonate containing industrial wastewater intensified using combined oxidation approaches. Ultrasonics Sonochemistry, 51, 69–76.

https://doi.org/10.1016/j.ultsonch.2018.10.018

[15] Jawale, R. H., Gogate, P. R., Pandit, A. B. (2014). Treatment of cyanide containing wastewater using cavitation-based approach. Ultrasonics Sonochemistry, 21(4), 1392-1399.

https://doi.org/10.1016/j.ultsonch.2014.01.025

[16] Samstag, R.W., Wicklein, E.A. (2014). A protocol for optimization of activated sludge mixing. 87th Annual Water Environment Federation Technical Exhibition and Conference. WEFTEC 2014, 7, 3614–3640.

[17] Do-Quang, Z., Cockx, A., Liné, A., Roustan, M. (1998). Computational fluid dynamics applied to water and wastewater treatment facility modeling. Environmental Engineering and Policy, 1, 137-147.

https://doi.org/10.1007/s100220050015

[18] Amini, E., Mehrnia, M. R., Mousavi, S. M., Mostoufi, N. (2013). Experimental study and computational fluid dynamics simulation of a full-scale membrane bioreactor for municipal wastewater treatment application. Industrial and Engineering Chemistry Research, 52(29), 9930-9939.

https://doi.org/10.1021/ie400632y

[19] Samstag, R. W., Ducoste, J. J., Griborio, A., Nopens, I., Batstone, D. J., Wicks, J. D., Laurent, J. (2016). CFD for wastewater treatment: an overview. Water Science and Technology, 74(3), 549-563.

https://doi.org/10.2166/wst.2016.249

[20] Matko, T., Chew, J., Wenk, J., Change, J., Hofman, J. (2021). Computational fluid dynamics simulation of two–phase flow and dissolved oxygen in a wastewater treatment oxidation ditch. Process Safety and Environmental Protection, 145, 340–353.

https://doi.org/10.1016/j.psep.2020.08.017

[21] Le Moullec, Y., Gentric, C., Potier, O., Leclerc, J. P. (2010). Comparison of systemic, compartmental and CFD modelling approaches: application to the simulation of a biological reactor of wastewater treatment. Chemical Engineering Science, 65(1), 343-350.

https://doi.org/10.1016/j.ces.2009.06.035

[22] Joshi, J. B. (2001). Computational flow modelling and design of bubble column reactors. Chemical Engineering Science, 56(21-22), 5893-5933.

https://doi.org/10.1016/S0009-2509(01)00273-1

[23] Teli, S. M., Pawar, V. S., Mathpati, C. (2020). Experimental and computational studies of aerated stirred tank with dual impeller. International Journal of Chemical Reactor Engineering, 18(3), 20190172.

https://doi.org/10.1515/ijcre-2019-0172

[24] Bouaifi, M., Hebrard, G., Bastoul, D., Roustan, M. (2001). A comparative study of gas hold-up, bubble size, interfacial area and mass transfer coefficients in stirred gas–liquid reactors and bubble columns. Chemical Engineering and Processing: Process Intensification, 40(2), 97-111.

https://doi.org/10.1016/S0255–2701(00)00129–X

[25] Bouaifi, M., Roustan, M. (1998). Bubble size and mass transfer coefficients in dual‐impeller agitated reactors. The Canadian Journal of Chemical Engineering, 76(3), 390-397.

https://doi.org/10.1002/cjce.5450760307

[26] Devi, T. T., Kumar, B. (2017). Mass transfer and power characteristics of stirred tank with Rushton and curved blade impeller. Engineering Science and Technology, an International Journal, 20(2), 730-737.

https://doi.org/10.1016/j.jestch.2016.11.005

[27] Komori, S., Murakami, Y. (1988). Turbulent mixing in baffled stirred tanks with vertical‐blade impellers. AIChE journal, 34(6), 932-937.

https://doi.org/10.1205/02638760152721613

[28] Rutherford, K., Lee, K. C., Mahmoudi, S. M. S., Yianneskis, M. (1996). Hydrodynamic characteristics of dual Rushton impeller stirred vessels. AIChE Journal, 42(2), 332-346.

https://doi.org/10.1002/aic.690420204

[29] Tomiyama, A., Celata, G. P., Hosokawa, S., Yoshida, S. (2002). Terminal velocity of single bubbles in surface tension force dominant regime. International Journal of Multiphase Flow, 28(9), 1497-1519.

https://doi.org/10.1016/S0301-9322(02)00032-0

[30] Roy, S. & Joshi, J. (2008). CFD Study of Mixing Characteristics of Bubble Column and External Loop Airlift Reactor. Asia‐Pacific Journal of Chemical Engineering, 3, 97– 105.

https://doi.org/10.1016/S0301-9322(02)00032-0

[31] Miller, D. N. (1974). Scale‐up of agitated vessels gas‐liquid mass transfer. AIChE Journal, 20(3), 445-453.

https://doi.org/10.1002/aic.690200303

[32] Buffo, M. M., Corrêa, L. J., Esperança, M. N., Cruz, A. J. G., Farinas, C. S., Badino, A. C. (2016). Influence of dual-impeller type and configuration on oxygen transfer, power consumption, and shear rate in a stirred tank bioreactor. Biochemical Engineering Journal, 114, 130-139.

https://doi.org/10.1016/j.bej.2016.07.003

[33] Lange, H., Taillandier, P., Riba, J. P. (2001). Effect of high shear stress on microbial viability. Journal of Chemical Technology and Biotechnology: International Research in Process, Environmental and Clean Technology, 76(5), 501-505.

https://doi.org/10.1002/jctb.401

[34] You, S. T., Raman, A. A. A., Shah, R. S. S. R. E., Mohamad Nor, M. I. (2014). Multiple-impeller stirred vessel studies. Reviews in Chemical Engineering, 30(3), 323-336.

https://doi.org/10.1515/revce-2013-0028