Operation of a submerged aerobic membrane bioreactor for decentralised municipal wastewater treatment in North Africa

A pilot-scale aerobic membrane bioreactor (MBR) was operated for 6.5 months, alongside a full-sized conventional activated sludge (AS) plant, treating high-strength domestic wastewater originating from Sfax in Tunisia. The main target was to investigate whether or not the MBR could produce effluent suitable for unrestricted crop irrigation in Tunisia, a target that the AS plant fails to achieve. Membrane performance analysis and energy benchmarking were also carried out. The MBR did produce irrigation quality water regardless of the mixed-liquor suspended solids (MLSS) or feed concentrations. The average chemical oxygen demand (COD) removal efficiency was 88% at an average MLSS concentration of 4.59 g L−1, and 89.7% at an average MLSS concentration of 9.52 g L−1. During membrane performance evaluation, a maximum sustainable membrane permeate flux of 12.81 L m−2 h−1, at an average mixed-liquor temperature of 24 °C and an average MLSS concentration of 9.21 g L−1 was maintained. Finally, energy benchmarking was carried out; the average energy consumption rate was 8.95 kWh d−1, corresponding to an average specific energy demand (SED) of 3.82 kWh m−3. This is a relatively high value compared to the AS plant, whose SED value is always lower than 3 kWh m−3, but further energy reduction is possible for the MBR as well as the AS plant effluent requires further treatment in order to be acceptable for unrestricted human crop irrigation; hence, additional energy input. The work demonstrates the potential impact of MBRs in decentralised domestic wastewater treatment in North Africa.

[1]  A. E. Greenberg,et al.  Standard Methods for the Examination of Water and Wastewater seventh edition , 2013 .

[2]  Gaspare Viviani,et al.  Start-up with or without inoculum? Analysis of an SMBR pilot plant , 2010 .

[3]  Peter Cornel,et al.  Oxygen transfer in membrane bioreactors treating synthetic greywater. , 2009, Water research.

[4]  Marco Ferraris,et al.  Start-up of a pilot-scale membrane bioreactor to treat municipal wastewater , 2009 .

[5]  H. Ng,et al.  Feasibility of submerged anaerobic membrane bioreactor (SAMBR) for treatment of low-strength wastewater. , 2008, Water science and technology : a journal of the International Association on Water Pollution Research.

[6]  A. Idris,et al.  Evaluation of using membrane bioreactor for treating municipal wastewater at different operating conditions , 2008 .

[7]  N. Topçu,et al.  Treatment investigation of the Erzurum City municipal wastewaters with anaerobic membrane bioreactors , 2007 .

[8]  P Pearce,et al.  Biomass effects on oxygen transfer in membrane bioreactors. , 2007, Water research.

[9]  Gianni Andreottola,et al.  Flux criticality and sustainability in a hollow fibre submerged membrane bioreactor for municipal wastewater treatment , 2007 .

[10]  Wolfgang Marquardt,et al.  Modeling submerged hollow-fiber membrane filtration for wastewater treatment , 2007 .

[11]  Pierre Le-Clech,et al.  Fouling in membrane bioreactors used in wastewater treatment , 2006 .

[12]  Robert W. Field,et al.  Critical and sustainable fluxes: Theory, experiments and applications , 2006 .

[13]  M. Ellouze,et al.  A Comparative Study on the Anaerobic Membrane Bioreactor Performance During the Treatment of Domestic Wastewaters of Various Origins , 2006, Environmental technology.

[14]  David M. Bagley,et al.  Anaerobic Membrane Bioreactors: Applications and Research Directions , 2006 .

[15]  N. V. Ndinisa,et al.  Fouling Control in a Submerged Flat Sheet Membrane System: Part I – Bubbling and Hydrodynamic Effects , 2006 .

[16]  Nazim Cicek,et al.  STATE-OF-THE-ART OF MEMBRANE BIOREACTORS: WORLDWIDE RESEARCH AND COMMERCIAL APPLICATIONS IN NORTH AMERICA , 2006 .

[17]  Werner Fuchs,et al.  Optimization of operational parameters for a submerged membrane bioreactor treating dyehouse wastewater , 2005 .

[18]  T. Arnot,et al.  In situ manipulation of critical flux in a submerged membrane bioreactor using variable aeration rates, and effects of membrane history , 2004 .

[19]  Cumali Kinaci,et al.  Rheological properties of activated sludge in a sMBR , 2004 .

[20]  Alain Grasmick,et al.  Membrane bioreactor fouling in sub-critical filtration conditions: a local critical flux concept , 2004 .

[21]  D. Eikelboom,et al.  Sewage treatment by a low energy membrane bioreactor. , 2003, Bioresource technology.

[22]  A. Fane,et al.  The use of gas bubbling to enhance membrane processes , 2003 .

[23]  Simon Judd,et al.  Impact of aeration, solids concentration and membrane characteristics on the hydraulic performance of a membrane bioreactor , 2003 .

[24]  Hang-Sik Shin,et al.  Sludge characteristics and their contribution to microfiltration in submerged membrane bioreactors , 2003 .

[25]  Anthony G. Fane,et al.  Fouling transients in nominally sub-critical flux operation of a membrane bioreactor , 2002 .

[26]  D. P. Lawrence,et al.  Membrane Bioreactors for Municipal Wastewater Treatment , 2002 .

[27]  Simon Judd,et al.  Aerobic MBRs for domestic wastewater treatment: a review with cost considerations , 2000 .

[28]  K. Hata,et al.  Domestic wastewater treatment by a submerged membrane bioreactor with gravitational filtration , 1999 .

[29]  April Garcia,et al.  Enumerating Salmonella in biosolids for compliance with pathogen regulations , 1995 .

[30]  Kazuo Yamamoto,et al.  Direct Solid-Liquid Separation Using Hollow Fiber Membrane in an Activated Sludge Aeration Tank , 1989 .