Energy reduction of a submerged membrane bioreactor using a polytetrafluoroethylene (PTFE) hollow-fiber membrane

Highlights

The fiber length and packing density of the PTFE membrane element were increased.

The MBR was stably operated under an SAD^m of 0.13 m³·m^-2·hr^-1.

Specific energy consumption was estimated to be less than 0.4 kWh·m^-3.

Abstract

In this study, we modified a polytetrafluoroethylene (PTFE) hollow-fiber membrane element used for submerged membrane bioreactors (MBRs) to reduce the energy consumption during MBR processes. The high mechanical strength of the PTFE membrane made it possible to increase the effective length of the membrane fiber from 2 to 3 m. In addition, the packing density was increased by 20% by optimizing the membrane element configuration. These modifications improve the efficiency of membrane cleaning associated with aeration. The target of specific energy consumption was less than 0.4 kWh·m^-3 in this study. The continuous operation of a pilot MBR treating real municipal wastewater revealed that the MBR utilizing the modified membrane element can be stably operated under a specific air demand per membrane surface area (SAD_m) of 0.13 m³·m^-2·hr^-1 when the daily-averaged membrane fluxes for the constant flow rate and flow rate fluctuating modes of operation were set to 0.6 and 0.5 m³·m^-2·d^-1, respectively. The specific energy consumption under these operating conditions was estimated to be less than 0.37 kWh·m^-3. These results strongly suggest that operating an MBR equipped with the modified membrane element with a specific energy consumption of less than 0.4 kWh·m^-3 is highly possible.

Graphical abstract

Keywords

Energy-saving / Membrane bioreactor / Polytetrafluoroethylene (PTFE) membrane / Hollow fiber / Power consumption

References

[1] Judd S. The MBR Book: Principles and Applications of Membrane Bioreactors in Water and Wastewater Treatment. Oxford: Elsevier, 2006

[2] Fenu A, Roels  J, Wambecq T,  De Gussem K,  Thoeye C,  De Gueldre G,  Van De Steene B. Energy audit of a full scale MBR system. Desalination, 2010, 262(1–3): 121–128

[3] Krzeminski P, van der Graaf  J H J M, van Lier  J B. Specific energy consumption of membrane bioreactor (MBR) for sewage treatment. Water Science and Technology, 2012, 65(2): 380–392

[4] Barillon B, Martin Ruel  S, Langlais C,  Lazarova V. Energy efficiency in membrane bioreactors. Water Science and Technology, 2013, 67(12): 2685–2691

[5] Buer T, Cumin  J. MBR module design and operation. Desalination, 2010, 262(1–3): 1073–1077

[6] Xiao K, Xu  Y, Liang S,  Lei T, Sun  J, Wen X,  Zhang H,  Chen C, Huang  X. Engineering application of membrane bioreactor for wastewater treatment in China: Current state and future prospect. Frontiers of Environmental Science & Engineering, 2014, 8(6): 805–819

[7] Krzeminski P, Leverette  L, Malamis S,  Katsou E. Membrane bioreactors—A review on recent developments in energy reduction, fouling control, novel configurations, LCA and market prospects. Journal of Membrane Science, 2017, 527: 207–227

[8] Tao G, Kekre  K, Oo M H,  Viswanath B,  Aliman M D Y,  Seah H. Energy reduction and optimisation in membrane bioreactors systems. Water Practice and Technology, 2010, 5(4): 88–93

[9] Itokawa H, Tsuji  K, Yamashita K,  Hashimoto T. Design and operating experiences of full-scale municipal membrane bioreactors in Japan. Water Science and Technology, 2014, 69(5): 1088–1093

[10] Hoque A, Kimura  K, Miyoshi T,  Yamato N,  Watanabe Y. Characteristics of foulants in air-sparged side-stream tubular membranes used in a municipal wastewater membrane bioreactor. Separation and Purification Technology, 2012, 93: 83–91

[11] Gil J A, Túa  L, Rueda A,  Montaño B,  Rodríguez M,  Prats D. Monitoring and analysis of the energy cost of an MBR. Desalination, 2010, 250(3): 997–1001

[12] Verrecht B, Maere  T, Nopens I,  Brepols C,  Judd S. The cost of a large-scale hollow fibre MBR. Water Research, 2010, 44(18): 5274–5283

[13] Verrecht B, James  C, Germain E,  Ma W, Judd  S. Experimental evaluation of intermittent aeration of a hollow fibre membrane bioreactor. Water Science and Technology, 2011, 63(6): 1217–1223

[14] Ho J, Smith  S, Roh H K. Alternative energy efficient membrane bioreactor using reciprocating submerged membrane. Water Science and Technology, 2014, 70(12): 1998–2003

[15] Kurita T, Kimura  K, Watanabe Y. Energy saving in the operation of submerged MBRs by the insertion of baffles and the introduction of granular materials. Separation and Purification Technology, 2015, 141(12): 207–213

[16] Monclús H, Dalmau  M, Gabarrón S,  Ferrero G,  Rodríguez-Roda I,  Comas J. Full-scale validation of an air scour control system for energy savings in membrane bioreactors. Water Research, 2015, 79(1): 1–9

[17] Yan X, Wu  Q, Sun J,  Liang P,  Zhang X,  Xiao K, Huang  X. Hydrodynamic optimization of membrane bioreactor by horizontal geometry modification using computational fluid dynamics. Bioresource Technology, 2016, 200: 328–334

[18] Miyoshi T, Yamamura  H, Morita T,  Watanabe Y. Effect of intensive membrane aeration and membrane flux on membrane fouling in submerged membrane bioreactors: Reducing specific air demand per permeate (SAD_p). Separation and Purification Technology, 2015, 148(25): 1–9

[19] Judd S. The status of industrial and municipal effluent treatment with membrane bioreactor technology. Chemical Engineering Journal, 2015, 305(1): 37–45

[20] Japan Sewage Works Association. Standard Methods for the Examination of Wastewater. Japan Sewage Works Association, Tokyo, Japan (in Japanese)

[21] Cornel P, Wagner  M, Krause S. Investigation of oxygen transfer rates in full scale membrane bioreactors. Water Science and Technology, 2003, 47(11): 313–319

[22] Krampe J, Krauth  K. Oxygen transfer into activated sludge with high MLSS concentrations. Water Science and Technology, 2003, 47(11): 297–303

[23] Germain E, Nelles  F, Drews A,  Pearce P,  Kraume M,  Reid E, Judd  S J, Stephenson  T. Biomass effects on oxygen transfer in membrane bioreactors. Water Research, 2007, 41(5): 1038–1044

RIGHTS & PERMISSIONS

2018 Higher Education Press and Springer–Verlag GmbH Germany, part of Springer Nature