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Expertise

Simon Judd

Simon Judd has over four decades of research and teaching experience in both the commercial and academic sectors. He held the Maersk Oil Professorial Chair in Environmental Engineering at Qatar University and is currently Emeritus Professor at Cranfield University, where he worked within the Water Science Institute for almost 30 years.

Simon’s expertise is based on his specialist research areas of membrane technology, chemical processes, and municipal/industrial water and wastewater treatment.

His research projects have typically involved practical pilot-scale investigation of real-world challenges, addressed through applied research. Applications have included:

  • municipal and industrial effluent
  • potable water
  • boiler feed water
  • swimming pool water, and
  • petroleum industry effluents.

His work in membranes and MBR (membrane bioreactor) technology has achieved the greatest impact, accounting for around 60% of his research publications.

Simon co-authored the original MBR reference book (‘Membrane bioreactors for wastewater treatment’, published in 2000) and is the sole author of both editions of ‘The MBR Book’ (2006, 2010), ‘Industrial MBRs’ (2014, 2020) and ‘Watermaths’ (2012, 2013, 2019). His latest book is ‘What are MBRs? A pocketbook of membrane bioreactor technology’ (2026). According to the academic database ‘Scholar GPS’ (December 2025), Simon is the #1 most highly-ranked scholar in bioreactor research.
https://scholargps.com/scholars/85326502760872/simon-judd

Away from membranes, Simon has conducted research into a range of chemical treatment technologies including:

  • chemical disinfection
  • coagulation/flocculation
  • magnetic conditioning
  • gas precipitation
  • chemical reduction
  • carbonation, and
  • algal photobioreactors.

He has procured over £10m of research in total in the UK and the Gulf, predominantly directly from industry but also from competitive bidding to national and international organisations such as EPSRC, EU-FP and QNRF.

“Simon Judd was commissioned by ALDAR Properties to provide expert advice on the operation of a large MBR sewage treatment plant constructed in the UAE (Abu Dhabi). The MBRs were not operating to the designed performance and Simon’s expert knowledge of MBR technology, experience and practicality assisted in guiding us to diagnose the operational problems and implement systems to successfully operate the plant.”
Andre Holder Pr. Eng. Aldar Properties - Yas Island Operations Project Manager
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Research Projects

Simon specialises in the application of membrane and chemical processes to municipal and industrial water and wastewater treatment.

Below are five examples of major research projects conducted from 2010 onwards.

Micropollutants rejection by membrane processes
  • Part of the UK National ‘Chemicals Investigation Programme’ to establish the fate of micropollutants in wastewater treatment installations.
  • Research included diagnosis of a full-scale reuse plant for pharmaceuticals rejection by RO and NF membranes at pilot scale (Garcia et al, 2013a), and metals fate (Garcia et al, 2013b).
  • This project was preceded by a review of metals fate in CAS and MBR plants (Santos and Judd, 2010a) and pilot-scale studies of the fate of pharmaceuticals in MBR plants (Reif et al, 2011; Santos et al, 2011).
Reuse of municipal wastewater
  • A series of projects sponsored by a UK water utility and conducted at a demonstration plant based on one of their wastewater treatment works, to examine various technologies for wastewater reuse:
    • MF-RO (Raffin et al, 2011, 2012ab)
    • coagulation (Hatt et al, 2011b)
    • microscreening (Hatt et al, 2011b)
    • activated carbon (Hatt et al, 2013ab), and
    • advanced oxidation (James et al, 2014).
  • James et al (2014) included a cost analysis of the various technologies challenged with the most recalcitrant micropollutant (metaldehyde). A benchmark review was subsequently published on water reuse implementation (Jeffrey et al, 2022).
MBR aeration efficiency and costs
  • Sponsored by a UK water utility, a pilot-scale study of an immersed hollow fibre MBR included mathematical modelling in collaboration with Ghent University.
  • The experimental work provided corroboration of the model (Verrecht et al, 2010a; Maere et al, 2011) as well as validation of the efficacy of intermittent membrane air scouring (Verrecht et al, 2011).
  • A widely-cited cost analysis of a large MBR was also presented (Verrecht et al, 2010b).
Clogging and ragging propensity determination in membrane bioreactors
  • This was a very significant body of work, comprising four projects for two US technology suppliers, a UK water company, and a Qatari municipality.
  • Bench and pilot-scale studies of flat sheet and immersed hollow fibre MBRs, along with a technical survey of established full-scale flat-sheet installations.
  • The work led to a number of papers in leading peer-reviewed journals (Stefanski et al, 2011; Zsirai et al, 2012, 2014; Buzatu et al, 2012, 2018).
Algal photobioreactors
  • An extensive three-year study at Qatar University on the use of algal PBRs to capture CO2 from power station flue gases and nutrients from municipal wastewaters.
  • Outcomes included:
    • A benchmark review of the state of the art (Judd et al, 2015)
    • A benchmark review of cost benefit (Judd et al, 2017)
    • Two process modelling-based technical papers (Al Ketife et al, 2016, 2019)
    • Technical papers on work conducted at bench scale − Shurair et al, 2016; Al Ketife et al, 2017ab, and
    • Technical papers on work conducted at pilot scale − Almomani et al, 2019ab.

Research Publications

Selected examples of Simon’s research publications since 2010 include:

Technical process optimisation
  • MBRs (Verrecht et al, 2010a; Maere et al, 2011),
  • Potable water membrane filtration (Porcelli and Judd, 2010a),
  • Wastewater reuse membrane filtration (Raffin et al, 2011, 2012a; Hatt et al, 2011a), and desalination (Raffin et al, 2011, 2012b),
  • Wastewater microscreening (Hatt et al, 2011b),
  • Sludge membrane thickening (Zsirai et al, 2014),
  • Coagulant recovery (Keeley et al, 2016ab), and
  • Granular activated carbon (Golea et al, 2020).
Cost analysis
  • MBRs (Verrecht et al, 2010b, 2012; Lo et al, 2015; Judd, 2017; Dizayee et al, 2023),
  • Potable water membranes (Porcelli and Judd, 2010ab; Judd & Carra, 2021), including ceramic membranes (Jarvis et al, 2022),
  • Coagulant recovery and reuse from potable water sludge (Keeley et al, 2012),
  • Reverse osmosis/nanofiltration of wastewater (Garcia et al, 2013b) and seawater (Judd, 2017),
  • Advanced oxidation of wastewater (James et al, 2014), and
  • Forward osmosis for wastewater treatment (Jalab et al, 2019).
Process technology review
  • MBR technology (Santos et al, 2010b; Santos et al, 2011; Judd, 2016, 2017),
  • Potable water membrane cleaning (Porcelli and Judd, 2010c),
  • Micropollutant fate (Santos and Judd, 2010a),
  • Wastewater reuse implementation (Raffin et al, 2013; Jeffrey et al, 2022),
  • Petroleum industry effluent treatment (Judd et al, 2014; Dizayee et al, 2023),
  • Algal technology (Judd et al, 2015, 2017), and
  • Forward osmosis implementation (Awad et al, 2019).

A complete list of all Simon’s publications is available on request.

References

Selected references from 2010
  • Al Ketife, A. M. D.,Almomani, F.,EL-Naas, M.,Judd, S., (2019). A technoeconomic assessment of microalgal culture technology implementation for combined wastewater treatment and CO2 mitigation in the Arabian gulf. Process Safety and Environmental Protection. 127, 90-102.
  • Al Ketife, A. M. D.,Judd, S.,Znad, H., (2016). A mathematical model for carbon fixation and nutrient removal by an algal photobioreactor. Chemical Engineering Science. 153, 354-362.
  • Al Ketife, A. M. D.,Judd, S.,Znad, H., (2017a). Optimization of cultivation conditions for combined nutrient removal and CO2 fixation in a batch photobioreactor. Journal of Chemical Technology and Biotechnology. 92(5), 1085-1093.
  • Al Ketife, A. M.,Judd, S.,Znad, H., (2017b). Synergistic effects and optimization of nitrogen and phosphorus concentrations on the growth and nutrient uptake of a freshwater chlorella vulgaris. Environmental Technology (United Kingdom). 38(1), 94-102.
  • Almomani, F.,Al Ketife, A.,Judd, S.,Shurair, M.,Bhosale, R. R.,Znad, H.,Tawalbeh, M., (2019a). Impact of CO2 concentration and ambient conditions on microalgal growth and nutrient removal from wastewater by a photobioreactor. Science of the Total Environment. 662, 662-671.
  • Almomani, F.,Judd, S.,Bhosale, R. R.,Shurair, M.,Aljaml, K.,Khraisheh, M., (2019b). Integrated wastewater treatment and carbon bio-fixation from flue gases using spirulina platensis and mixed algal culture. Process Safety and Environmental Protection. 124, 240-250.
  • Awad, A. M.,Jalab, R.,Minier-Matar, J.,Adham, S.,Nasser, M. S.,Judd, S. J., (2019). The status of forward osmosis technology implementation. Desalination. 461, 10-21.
  • Buzatu, P.,Qiblawey, H.,Odai, A.,Jamaleddin, J.,Nasser, M. S.,Judd, S., (2018). Clogging vs. fouling in immersed membrane bioreactors. Water Research. 144, 46-54.
  • Buzatu, P.,Zsirai, T.,Aerts, P.,Judd, S.J., (2012). Permeability and clogging in an immersed hollow fibre membrane bioreactor. Journal of Membrane Science. 421-422, 342-348.
  • Dizayee, K.K.H.,Raheem, A.M.,Judd, S.J., (2023). The Cost Benefit of Refinery Effluent Pretreatment Upstream of Membrane Bioreactors. Membranes. 13, 715.
  • Garcia, N.,Moreno, J.,Cartmell, E.,Rodriguez-Roda, I.,Judd, S., (2013a). The application of microfiltration-reverse osmosis/nanofiltration to trace organics removal for municipal wastewater reuse. Environmental Technology (United Kingdom). 34 (24), 3183-3189.
  • Garcia, N.,Moreno, J.,Cartmell, E.,Rodriguez-Roda, I.,Judd, S., (2013b). The cost and performance of an MF-RO/NF plant for trace metal removal. Desalination. 309, 181-186.
  • Golea, D. M.,Jarvis, P.,Jefferson, B.,Moore, G.,Sutherland, S.,Parsons, S. A.,Judd, S. J., (2020). Influence of granular activated carbon media properties on natural organic matter and disinfection by-product precursor removal from drinking water. Water Research. 174, 115613.
  • Hatt, J.W.,Germain, E.,Judd, S.J., (2013a). Granular activated carbon for removal of organic matter and turbidity from secondary wastewater. Water Science and Technology. 67 (4), 846-853.
  • Hatt, J.W.,Germain, E.,Judd, S.J., (2013a). Powdered Activated Carbon-Microfiltration for Waste-Water Reuse. Separation Science and Technology (Philadelphia). 48 (5), 690-698.
  • Hatt, J.W.,Germain, E.,Judd, S.J., (2011a). Precoagulation-microfiltration for wastewater reuse. Water Research. 45 (19), 6471-6478.
  • Hatt, J.W.,Judd, S.J.,Germain, E., (2011b). Screening optimisation for indirect potable reuse. Water Science and Technology. 63 (12), 2846-2852.
  • Jalab, R.,Awad, A.,Nasser, M.,Miner-Matar, J.,Adham, S.,Judd, S., (2019). An empirical determination of the whole-life cost of FO-based open-loop wastewater reclamation technologies. Water Research. 163, 114879.
  • James, C.P.,Germain, E.,Judd, S., (2014). Micropollutant removal by advanced oxidation of microfiltered secondary effluent for water reuse. Separation and Purification Technology. 127, 77-83.
  • Jarvis, P.,Carra, I.,Jafari, M.,Judd, S. J., (2022). Ceramic vs polymeric membrane implementation for potable water treatment. Water Research. 215, 118269.
  • Jeffrey, P.,Yang, Z.,Judd, S. J., (2022). The status of potable water reuse implementation. Water Research. 214, 118198.
  • Judd, S. J., (2016). The status of industrial and municipal effluent treatment with membrane bioreactor technology. Chemical Engineering Journal. 305, 37-45.
  • Judd, S. J., (2017). Membrane technology costs and me. Water Research. 122, 1-9.
  • Judd, S. J.,Al Momani, F. A. O.,Znad, H.,Al Ketife, A. M. D., (2017). The cost benefit of algal technology for combined CO2 mitigation and nutrient abatement. Renewable and Sustainable Energy Reviews. 71, 379-387.
  • Judd, S.,Carra, I., (2021). Low-pressure membrane technology for potable water filtration: true costs. Water Research. 175, 116826.
  • Judd, S.,Qiblawey, H.,Al-Marri, M.,Clarkin, C.,Watson, S.,Ahmed, A.,Bach, S., (2014). The size and performance of offshore produced water oil-removal technologies for reinjection. Separation and Purification Technology. 134, 241-246.
  • Judd, S.,van den Broeke, L. J. P.,Shurair, M.,Kuti, Y.,Znad, H., (2015). Algal remediation of CO2 and nutrient discharges: A review. Water Research. 87, 356-366.
  • Keeley, J.,Jarvis, P.,Judd, S.J., (2012). An economic assessment of coagulant recovery from water treatment residuals. Desalination. 287, 132-137.
  • Keeley, J.,Jarvis, P.,Smith, A. D.,Judd, S. J., (2016a). Coagulant recovery and reuse for drinking water treatment. Water Research. 88, 502-509.
  • Keeley, J.,Smith, A. D.,Judd, S. J.,Jarvis, P., (2016b). Acidified and ultrafiltered recovered coagulants from water treatment works sludge for removal of phosphorus from wastewater. Water Research. 88, 380-388.
  • Lo, C. H.,McAdam, E.,Judd, S., (2015). The cost of a small membrane bioreactor. Water Science and Technology. 72(10), 1739-1746.
  • Maere, T.,Verrecht, B.,Moerenhout, S.,Judd, S.,Nopens, I., (2011). BSM-MBR: A benchmark simulation model to compare control and operational strategies for membrane bioreactors. Water Research. 45 (6), 2181-2190.
  • Porcelli, N.,Judd, S., (2010a). Effect of cleaning protocol on membrane permeability recovery: A sensitivity analysis. Journal of American Water Works Association. 102 (12), 78-86.
  • Porcelli, N.,Judd, S., (2010b). Chemical cleaning of potable water membranes: The cost benefit of optimisation. Water Research. 44 (5), 1389-1398.
  • Porcelli, N.,Judd, S., (2010c). Chemical cleaning of potable water membranes: A review. Separation and Purification Technology. 71 (2), 137-143.
  • Raffin, M.,Germain, E.,Judd, S., (2012b). Assessment of fouling of an RO process dedicated to indirect potable reuse. Desalination and Water Treatment. 40 (1-6), 302-308.
  • Raffin, M.,Germain, E.,Judd, S., (2011). Optimising operation of an integrated membrane system (IMS) - A Box-Behnken approach. Desalination. 273 (1), 136-141.
  • Raffin, M.,Germain, E.,Judd, S., (2013). Wastewater polishing using membrane technology: A review of existing installations. Environmental Technology (United Kingdom). 34 (5), 617-627.
  • Raffin, M.,Germain, E.,Judd, S.J., (2012a). Influence of backwashing, flux and temperature on microfiltration for wastewater reuse. Separation and Purification Technology. 96, 147-153.
  • Reif, R.,Santos, A.,Judd, S.J.,Lema, J.M.,Omil, F., (2011). Occurrence and fate of pharmaceutical and personal care products in a sewage treatment works. Journal of Environmental Monitoring. 13 (1), 137-144.
  • Santos, A.,Barton, P.,Cartmell, E.,Coulon, F.,Crane, R.S.,Hillis, P.,Lester, J.N.,Stephenson, T.,Judd, S.J., (2010a). Fate and behaviour of copper and zinc in secondary biological wastewater treatment processes: II Removal at varying sludge age. Environmental Technology. 31 (7), 725-743.
  • Santos, A.,Judd, S., (2010b). The commercial status of membrane bioreactors for municipal wastewater. Separation Science and Technology. 45 (7), 850-857.
  • Santos, A.,Judd, S., (2010a). The fate of metals in wastewater treated by the activated sludge process and membrane bioreactors: A brief review. Journal of Environmental Monitoring. 12 (1), 110-118.
  • Santos, A.,Ma, W.,Judd, S.J., (2011). Membrane bioreactors: Two decades of research and implementation. Desalination. 273 (1), 148-154.
  • Santos, A.,Reif, R.,Hillis, P.,Judd, S.J., (2011). Fate and removal of permethrin by conventional activated sludge treatment. Environmental Technology. 32 (12), 1367-1373.
  • Shurair, M. S.,Almomani, F.,Judd, S.,Bhosale, R. R.,Kumar, A., (2016). Potential for green algae spirulina to capture carbon dioxide from gas stream. Advanced Materials - TechConnect Briefs. 2, 141-143.
  • Stefanski, M.,Kennedy, S.,Judd, S., (2011). The determination and origin of fibre clogging in membrane bioreactors. Journal of Membrane Science. 375 (1-2), 198-203.
  • Verrecht, B.,James, C.,Germain, E.,Birks, R.,Barugh, A.,Pearce, P.,Judd, S., (2012). Economical evaluation and operating experiences of a small-scale MBR for non-potable reuse. Journal of Environmental Engineering (United States). 138 (5), 594-600.
  • Verrecht, B.,James, C.,Germain, E.,Ma, W.,Judd, S., (2011). Experimental evaluation of intermittent aeration of a hollow fibre membrane bioreactor. Water Science and Technology. 63 (6), 1217-1223.
  • Verrecht, B.,Maere, T.,Benedetti, L.,Nopens, I.,Judd, S., (2010a). Model-based energy optimisation of a small-scale decentralised membrane bioreactor for urban reuse. Water Research. 44 (14), 4047-4056.
  • Verrecht, B.,Maere, T.,Nopens, I.,Brepols, C.,Judd, S., (2010b). The cost of a large-scale hollow fibre MBR. Water Research. 44 (18), 5274-5283.
  • Zsirai, T.,Buzatu, P.,Aerts, P.,Judd, S., (2012). Efficacy of relaxation, backflushing, chemical cleaning and clogging removal for an immersed hollow fibre membrane bioreactor. Water Research. 46 (14), 4499-4507.
  • Zsirai, T.,Wang, Z.-Z.,Gabarrón, S.,Connery, K.,Fabiyi, M.,Larrea, A.,Judd, S.J., (2014). Biological treatment and thickening with a hollow fibre membrane bioreactor. Water Research. 58, 29-37.
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Teaching and Training

Simon Judd has over forty years’ experience delivering training courses in the field of water and wastewater treatment.

He has been Course Director of an MSc course and has developed and managed four Masters-level course modules. He has delivered countless continuing professional development (CPD) short courses, in the UK and across the world, including The MBR Short Course at Cranfield University between 2000 and 2015.

See our Clients and Case Studies page.

“I attended The MBR Course in Doha in March 2015. It was money well spent. A great overview, from theoretical aspects to detailed case studies. Plus you end up with comprehensive presentation material and a reference book. I felt it was a bargain.”
Werner Redtenbacher ILF Consulting Engineers Austria GmbH