Position Associate Professor Qualifications PrEng (SA), PE (MD-USA), MSc (UKY), PhD (UKY), MSAICE, MASCE, MAWWA, MWISA Telephone +27 12 420 5894 Fax +27 12 362 5089 E-mail [email protected]

Mission

Research interests

• Biological remediation of toxic metals and radionuclides
• Advanced oxidation and photocatalytic degradation of taste and odour casing compounds, recalcitrant toxic organics and organic micropollutants in water
• In situ bioremediation processes 
• Biological and ecological modelling (mathematics of ecology) 
• Biofilms and microbial culture dynamics in natural systems 
• Radioactive waste treatment, waste minimisation and recovery
• Hydrodynamic modelling of suspended particles and separation processes
• Rural water resources development

Books / Book chapters

1. Mtimunye P.J. and Chirwa E.M.N. (2013). Bioremediation of radiotoxic elements under natural environmental conditions. In B. Patil Y.B. and Rao P., (Eds.), Applied Bioremediation - Active and Passive Approaches, InTech Open Publishers, Chapter 8, pp. 177-206. Download [ISBN 978-953-51-1200-6].
2. Chirwa E.M.N. (2011). Developments in bioremediation for separation/recovery. K.L. Nash and G.J. Lumetta (Eds.), in Advanced Separation Techniques for Nuclear Fuel Reprocessing and Radioactive Waste Treatment, Woodhead Publishing, Ltd, Cambridge, UK, Chapter 15, pp. 436-472. [ISBN 978-18456-901-9].
3. Chirwa E.M.N. and Molokwane P.E. (2011). Biological Cr(VI) Reduction: Microbial Diversity, Kinetics and Biotechnological Solutions to Pollution.  In A. Sofo (Ed.), Biodiversity, InTech Online Publishers, United Kingdom. Chapter 5, pp. 75-100. Open Access Download [ISBN 978-953-307-715-4].
4. Chirwa E.M.N. (2012). Bioremediation of uranium, transuranic waste and fission products in nuclear waste. R. Arora (Ed.), In Microbial Biotechnology: Energy and Environment, CAB International, Oxon, United Kingdom, Chapter 17, pp. 310-347. [ISBN 9781845939564].

Journal articles (most cited)

1. Birungi Z.S., Chirwa E.M.N. (2014). The kinetics of uptake and recovery of lanthanum using freshwater algae as biosorbents: comparative analysis. Bioresource Technology. (Published Online : /dx.doi.org/10.1016/j.biortech.2014.01.033).
2. Sithebe N.P., Methula B., Chirwa E.M.N. (2014). A finite velocity simulation of sedimentation behaviour of flocculating particles – a real time model evaluation. Water SA, 40 (1), 109-116.
3. Mtimunye P.J., Chirwa E.M.N. (2014). Finite difference simulation of biological chromium (VI) removal in aquifer media columns. Water SA, 40 (20), 359-368.
4. Mtimunye P.J., Chirwa E.M.N. (2014). Biochemical optimisation and control of uranium (VI) reduction in facultative uranium VI reducing cultures. Chemosphere. (In Press).
5. Makgato S.S., Chirwa E.M.N. (2014). Photoassisted Biodegradation of Irradiated Organics in Simulated Nuclear Waste. Water Environment Research. (In Press).
6. Chirwa E.M.N., Lebitso M.T. (2014). Protein from WAS as a nutritional supplement in chicken feed. Water Science and Technology, 69 (7), 1419-1425. 
7. Chirwa E.M.N., Venter I., Wienand H. (2013). Biological Cr(VI) immobilisation in saturated aquifer zone using culture inoculated soil columns. Water Science and Technology, 67 (10) pp. 2321-2329.
8. Molokwane P.E., Chirwa E.M.N. (2013). Modelling biological Cr(VI) reduction in aquifer microcosm column systems. Water Science and Technology, 67 (12) pp. 2733-2738.
9. Chirwa E.M.N., Mampholo C.T., Fayemiwo O. (2013). Biosurfactants as demulsifying agents for oil recovery from oily sludge – performance evaluation. Water Science and Technology, 67 (12) pp. 2875-2881.
10. Chirwa E.M.N. and Lebitso M.T. (2012). Assessment of nutritional value of single-cell protein from waste-activated sludge as a protein supplement in poultry feed. Water Environment Research, 84 (12), 2106-2114.
11. Bamuza-Pemu E.E. and Chirwa E.M.N. (2012). Photocatalytic degradation of geosmin: Reaction pathway analysis. Water SA, 38 (5), 689-696.
12. Ramatsoma M.S. and Chirwa E.M.N. (2012). Computational simulation of flocculent sedimentation based on experimental results. Water Science and Technology, 65 (6), 1007-1013.
13. Tikilili P.V. and Chirwa E.M.N. (2011). Characterization and Biodegradation of Polycyclic Aromatic Hydrocarbons in Radioactive Wastewater. Journal of Hazardous Materials, 192 (3), 1589-1596.
14. Ngwenya N. and Chirwa E.M.N. (2011). Biological removal of cationic fission products from nuclear wastewater. Water Science and Technology. Vol 63 (1), 124-128.
15. Chabalala S. and Chirwa E.M.N. (2010). Uranium(VI) reduction and removal by high performing purified anaerobic cultures from mine soil. Chemosphere, 78 (1), pp. 52-55.
16. Ngwenya N. and Chirwa E.M.N. (2010). Single and binary component sorption of the fission products Sr²⁺, Cs⁺ and Co²⁺ from aqueous solutions onto sulphate reducing bacteria. Minerals Engineering, 23 (6), 463-470.
17. Chabalala S. and Chirwa E.M.N. (2010).Removal of Uranium(VI) under Aerobic and Anaerobic Conditions using an Indigenous Mine Consortium. Minerals Engineering, 23 (6), 526-531.
18. Makgato S.S. and Chirwa E. (2010). Performance evaluation of AOP/biological hybrid system for treatment of recalcitrant organic compounds. International Journal of Chemical Engineering. vol. 2010, doi:10.1155/2010/590169.
19. Nikiema J., Nkhalambayausi-Chirwa E.M., and Andrés Y. (2010). Quality and Pollution Control Technologies for Water, Air, and Soil Editorial. International Journal of Chemical Engineering. vol. 2010. Article ID 252131, 2 pages, 2010.
20. Molokwane P.E. and Nkhalambayausi-Chirwa E.M., 2009, Microbial culture dynamics and chromium (VI) removal in packed-column microcosm reactors. Water Science and Technology, 60 (2), pp. 381-388.
21. Molokwane P.E., Nkhalambayausi-Chirwa E.M., and Meli K.C., 2008. Chromium (VI) reduction in activated sludge bacteria exposed to high chromium loading: Brits culture (South Africa). Water Research, 42 (17), pp. 4538-4548.
22. Molokwane P.E., Meli C.K. and Chirwa E.M.N., 2008. Chromium (VI) reduction in activated sludge bacteria exposed to high chromium Loading. Water Science and Technology, 58 (2), pp. 399-405.
23. Molokwane P.E. and Chirwa E.M.N., 2006. Biological Cr(VI) reduction in indigenous sludge cultures from Gauteng, South Africa. Water Science and Technology, 54 (10), pp. 177–184.
24. Chirwa E.N-. and Wang Y.T., 2005. Modeling Cr(VI) reduction and phenol degradation in a coculture biofilm reactor. ASCE Journal of Environmental Engineering, 131 (11), pp. 1495-1506.
25. Chirwa E.M.N-. and Wang Y.T. (2004). Modeling Cr(VI) reduction in a Bacillus sp. pure culture biofilm reactor. Biotechnology and Bioengineering, 87 (7), 874-883.
26. Chirwa E.N.- and Wang Y.T. (2001). Simultaneous chromium(VI) reduction and phenol degradation in a fixed-film coculture bioreactor: reactor performance. Water Research, 35 (8), 1921-1932.
27. Chirwa E.N. and Wang Y.T. (2000). Simultaneous Cr(VI) reduction and phenol degradation in an anaerobic consortium of bacteria. Water Research, 34 (8), 2376-2384.
28. Wang Y-.T. Chirwa E.N. and Shen H. (2000). Cr(VI) reduction in a continuous-flow coculture reactor. ASCE Journal of Environmental Engineering, 126 (4), 300-306. 
29. Chirwa E.M.N. and Wang Y.T. (1997). Hexavalent chromium reduction by Bacillus sp. in a packed-bed bioreactor. Environmental Science and Technology, 31 (5), pp. 1446-1451. 
30. Chirwa E.M.N. and Wang Y.T. (1997). Chromium(VI) reduction by Pseudomonas fluorescens LB300 in a fixed-film bioreactor. ASCE Journal of Environmental Engineering, 123 (8), pp. 760-766. 

Conferences publications (past 2 years) 

1. Chirwa E.M.N., Molokwane P.E., Ngwenya N., Tikilili P.V. (2013). Bioremediation of toxic organics and recovery of radioactive elements from nuclear wastewater. 28th International Conference on Solid Waste Management, 10-13 March 2013, Philadelphia, Pennsylvania, USA.
2. Chirwa E.M.N., Lebitso M.T. (2013). Protein from WAS as a nutritional supplement in chicken feed. 10th IWA Leading Edge Conference on Water & Wastewater Technologies, 2-6 June 2013, Bordeaux, France.
3. Kaimbi L.A., Chirwa E.M.N. (2013). Remobilization of trivalent chromium and the regeneration of in situ permeable reactive barriers during operation. 16th Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES’13), 29 September - 2 October 2013, Rhodes, Greece. In Chemical Engineering Transactions, vol 35, pp. 835-840. ISBN 978-88-95608-26-6.
4. Bamuza-Pemu E.E., Chirwa E.M.N. (2013). Profile of aromatic intermediates of titanium dioxide mediated degradation of phenol. 16th Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES’13), 29 September - 2 October 2013, Rhodes, Greece. In Chemical Engineering Transactions, vol 35, pp. 1333-1338. ISBN 978-88-95608-26-6.
5. Fayemiwo A., Chirwa E.M.N. (2013). Oil recovery from oily sludge using biosurfactant producing bacteria as demulsifying agents. 16th Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES’13), 29 September - 2 October 2013, Rhodes, Greece.
6. Dimite A.F., Chirwa E.M.N. (2013). Sulphur recovery using a sulphide oxidizing bacterium. 16th Conference of Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (PRES’13), 29 September - 2 October 2013, Rhodes, Greece.
7. Mtimunye P.J., Chirwa E.M.N. (2013). Biological reduction of radionuclides under facultative anaerobic conditions using radiation tolerant consortium. 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013). 5-9, October 2013, McCormick Place South, Chicago, Illinois, USA.
8. Birungi Z.S., Chirwa E.M.N. (2013). Phytoremediation of lanthanum using algae from eutrophic freshwater sources. 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013). 5-9, October 2013, McCormick Place South, Chicago, Illinois, USA.
9. Chirwa E.M.N., Fayemiwo O., Mampholo, C.T. (2013). Oil recovery from oily sludge using biosurfactant producing bacteria as demulsifying agents. 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2013). 5-9, October 2013, McCormick Place South, Chicago, Illinois, USA.
10. Chirwa E.M.N., Tikilili P.V. and Ngwenya N. (2012). Degradation, separation and recovery of fuel elements from nuclear wastewater. IWA World Water Congress & Exhibition, 16-21 September 2012, Busan, South Korea.
11. Molokwane P.E. and Chirwa E.M.N. (2012).  Modelling biological Cr(VI) reduction in aquifer microcosm column systems.  IWA World Water Congress & Exhibition, 16-21 September 2012, Busan, South Korea.
12. Sithebe N.P., Methula B. and Chirwa E.M.N. (2012). Advanced model of flocculent sedimentation based on fundamental physics of settling particles. IWA World Water Congress & Exhibition, 16-21 September 2012, Busan, South Korea.
13. Chabalala S. and Chirwa E.M.N. (2012). Modelling U(VI) reduction by Pseudomonas stutzeri. Proc. 3rd International Conference on Industrial Biotechnology (IBIC 2012), 24-27 June, 2012, Palermo, Italy. In Chemical Engineering Transactions, Vol. 37, pp. 265-270.

Research supervision

    Graduated Ph.D. Students

• Pulane E. Molokwane. (Ph.D., 2010) – Simulation of in situ bioremediation of Cr(VI) in groundwater aquifer environments using a microbial culture barrier. 
• Nonhlanhla Ngwenya. (Ph.D., 2011) – Bioremediation of metallic fission products in nuclear waste: biosorption and biorecovery.
• Emomotimi Bamuza-Pemu. (Ph.D., 2014) – Photocatalytic degradation of phenolic compounds and semi volatile algal metabolites in Water.

    Graduated Masters' Students

• Nomcebo Sithebe (M.Eng., 2014). Flocculent particle sedimentation simulation using velocity and fractal particle sedimentation theory.
• Chris Mahlathi (M.Eng., 2014). In-stream water quality modelling and optimisation by mixed-integer programming: simulation and application in actual system.
• Julienne Ngo Yebga (M.Sc., 2014), Photocatalytic Oxidative Efficiency of Titanium Dioxide: The Effect of catalyst loading and the effect of nitrogen bubbling on the photocatalytic degradability of selected compounds.
• Esther Lekalake (M.Sc., 2014). Stabilisation of Cr(VI) in a ferrochrome mine dump simulated environment using Cr(VI) reducing organisms and ferric/ferrous catalyst.
• Zack Khuzwayo (M.Sc., 2012). Prevalence and treatment of emerging pollutants and Endocrine Disrupting Chemicals in South African Catchments.
• Lelanie Bester (M.Eng., 2012). Feasibility of full reclamation of gold mine process water. Phumza Tikilili (M.Sc., 2011, with distinction). Biodegradation of complex organic compounds originating from nuclear and industrial radioactive waste.
• Kakonge C. Meli (M.Eng., 2009, with distinction). Microbial Cr(VI) reduction in indigenous culture isolates from dried activated sludge.
• Susann Marais (M.Eng., 2008, with wistinction). Enzymatic hydrolysis with commercial enzymes of a xylan extracted from hardwood pulp.
• Erin Elliot (M.Eng., 2009, with disctinction). Bavianspoort Wastewater Treatment Works – feasibility study for the upgrading and extension of the works.
• Stanford Makgato (M.Tech., graduated 2010). Photoassisted biodegradation of recalcitrant organic compounds originating from the nuclear fuel recovery process.
• Moses Lebitso (M.Sc., graduated 2010). Assessment of nutritional value os Single Cell Protein from waste activated sludge.
• Simphiwe Chabalala (M.Sc., 2011, with distinction). Characterisation of Uranium(VI) reduction and removal using indigenous cultures of anaerobic bacteria.
• Johanna Mtimunye (M.Sc., 2011, with distinction). Inhibition kinetics for Cr(VI) reduction by indigenous consortium cultures from sludge.
• Zinzi Mboweni (M.Sc., graduated 2011). Microbial culture barrier for Cr(VI) contamination containment.

     Current Students (Ph.D. & M's)

• Johanna Mtimunye (Ph.D., finalist). Biological reduction of uranium (VI) in anaerobic and microaerobic environments.
• Zainab Birungi (Ph.D., finalist). Biosorption of heavy metals in industrial wastewater using fresh water algae. 
• Phumza Tikilili (Ph.D., finalist). Characterisation of Indigenous Anaerobic Ammonium Oxidising (Anammox) Bacteria Grown in Microaerobic Environments.
• Boitumelo Mashangoane (Ph.D. candidate, year 3). Biological separation of metallic elements in mine wastewater.
• Zack Khuzwayo (Ph.D. candidate, year 2). Prevalence and treatment of emerging pollutants and Endocrine Disrupting Chemicals in South African Catchments.
• John Njalam'mano (Ph.D. candidate, year 1). Feacal sludge management in southern African cites using the peri-urban environment of South African Cities as case studies.
• Ellie Rava (Ph.D. candidate, year 1). Treatment of coal gasification wastewater stream in bio-augmented integrated fixed-film activated sludge process.
• Fisseha Bezza (M.Eng., finalist). Biological degradation of polycyclic aromatic hydrocarbons using biosurfactant producing bacteria.
• Tony Igboamalu (M.Eng., finalist). Metabolically linked reduction of chromium (VI) with arsenic oxidation in biofilm systems.
• Lapaka Kaimbi (M.Sc., finalist). Remobilisation of tetravalent chromium and regeneration of in situ permeable reactive barriers during operation.
• Alesia Dimite (M.Sc., finalist). Optimisation of sulfide oxidation and sulfur recovery from acid mine drainage.
• Oluwademilade Fayemiwo (M.Sc., finalist). Biological recovery of oil from oily sludge using biosurfactant as emulsifying agent.
• Alicia Enslin (M.Eng., year 1). Immobilisation of metallic species in underground water using nanotechnology.
• Sakiah Lekoadu (M.Sc., finalist). The use of Phytoremediation technique for treatment of contaminated lead and acid mine drainage soils.

Postgraduate courses

• Water Quality Management (WQB 780/787)
• Biological Water Treatment (WBW 780/787)
• Water Supply and Sanitation (EWM 822)
• Principles of Environmental Engineering (CEM 780/787)

Upcoming events

     Short Courses

• Environmental Management & Regulation:                                                  10-13 March 2014 
• Operation of Water and Wastewater Treatment Plants:                               23-27 June 2014 
• Water Quality Management and Effluent Treatment:                                   18-22 August 2014
• Environmental Management & Regulation:                                                   8-11 September 2014
• Automation and Process Control of Water Treatment Works (8 days)         To be announced

     Conferences and Symposia - 2014

• Water Institute of Southern Africa (WISA) Biennial Conference & Exhibition, 25 - 29 May 2014, Mbombela, Mpumalanga, South Africa. http://www.wisa.org.za/Event_Details. 
• 21st International Congress of Chemical and Process Engineering CHISA 2014 Prague, 23-27 August 2014 Prague, Czech Republic. http://www.chisa.cz/2014/.
• IWA World Water Congress & Exhibition, 21-26 September 2014, Lisbon Congress Centre, Praça das Indústrias, Lisbon, Portugal. http://www.iwa2014lisbon.org/.
• 86th Annual Water Environment Federation Technical Exhibition and Conference (WEFTEC 2014), New Orleans Morial Convention Center, New Orleans, Louisiana, USA. http://www.weftec.org/.