Staff Login



Department of Chemical & Process Engineering

University of Moratuwa



B.Sc. Eng.(Hons) Moratuwa, M.Sc. (UMIST-UK) ,Ph.D (NTNU-Norway)


Senior Lecturer Grade I

 Contact Details

E - Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Phone: +94 112 650301       Ext :4122
 +94 112 650 281  

Fields of Interest

Energy efficiency 
Environmental biotechnology
Waste water and solid waste treatments
Process modeling and simulation
CFD (Computational Fluid Dynamics) modeling

Lab Coordinated 

Environmental Laboratory


   1989-1993   B.Sc (Eng) Hons Degree, University of Moratuwa, Sri Lanka.

                  First Class (Hons) degree in Chemical Engineering

1995-   1997      M.Sc by Research Degree, University of Manchester Institute of Science and Technology,         England       

                           Thesis Title :Targeting and Designing of Heat exchanger network  of chemical Process considering diffetent film coefficients.

 2009    2009     Degree of Doctor of Phyloshopy

(on 26 th October 2009 from Norwagean University of Science and Technology (NTNU), Norway)

   Thesis title: Anaerobic digestion process using membrane integrated micro aeration

   2012     Postdoctoral fellowship at Walloon Centre of Industrial Biology at University of                      

                Liege, Belgium. Title : Biohydrogen production 


Ongoing research projects

Study on effect of fats and oil on anaerobic digestion of food wastes

Optimization of bio methane production process for co digestion of sewerage sludge and municipal solid wastes

Dynamic modeling and simulation of plug flow reactor solid waste treatment

Modeling and simulation of effect of scale formation on evaporators in sugar industry

CFD (Computational Fluid Dynamics) modeling of cinnamon dryer

Feasibility Study of Biogas Generation from Municipal Solid Waste(MSW) and Sewerage Generated within the Colombo city Limits 

Development of new biogas storage technique to be applied in transportation 

Local Publications

P.G. Rathnasiri, Hayun and R. Bakke
Transient response and stability of anaerobic reactors following intermittent Feeding.13th Symposium of the Engineering Research Unit (ERU), University of Moratuwa 10th October, 2007 at Hotel Taj Samudra, Colombo

b. P. G. Rathnasiri, M. A. D. I. C. Kularatna, A. A. P. de Alwis

Potential of biomethane as a transport fuel and development of pilot scale co-digestion plant for treating source separated canteen waste generated at University of Moratuwa.13th Symposium of the Engineering Research Unit (ERU), University of Moratuwa 10th October, 2007 at Hotel Taj Samudra, Colombo

M.A.D.I.C. Kularatna, Alwis, P.G. Rathnasiri

Review on upgrading and application of biogas as a vehicle fuel, 14th ERU Symposium , 2008

P.G. Rathnasiri, A.A.P de Alwis, D.W. Nuditha and M.A.D.I.C. Kularatne

Development of New Pilot scale Co- Digestion Anaerobic Process for Solid Waste Exploring new spheres for a better future, 04 December 2009, Annual symposium 2009, organized by General Sir John Kotelawala Defence University, Srilanka

Dilnayana, K.W.N., Kularathne M.A.D.I.C., Rathnasiri P.G., Joseph P.G. and De Alwis A.A.P.

Optimization of an anaerobic co-digestion process and use of Bio methane as a transport fuel National Energy Symposium, 4th -8th August 2010, organized by Srilanka Sustainable Energy Authority, Ministry of Power and Energy.

S. L. J. Wijeyekoon, K. Raamshangar and P.G. Rathnasiri

Enhancement of Hydrolysis of Anaerobic Process by Peroxonation Pre-treatment( IESL- 2011)


 Previous Researches and publications 

International conferences

P.G.Rathnasiri, J.E. Johansen, C. B. Drangeid and R.Bakke 
Transient co-digestion plant behavior 4th International Symposium, Anaerobic Digestion of Solid Waste, August 31- September 2, 2005, Copenhagen, Denmark

P.G. Rathnasiri, Carlos Dinamarca and R. Bakke
Membrane controlled micro-aeration in digesters. Baltic Biorefinery Symposium, 26-28 May, 2005, Aalborg University Esberg, Denmark.

B.R.H. Peiris, P.G. Rathnasiri, J.E. Johansen, A.Kuhn and R.Bakke
Hydrogen from food residues Baltic Biorefinery Symposium, 26-28 May, 2005, Aalborg University Esberg, Denmark.

B. R. H. Peiris, P.G. Rathnasiri, J.E. Johansen, A. Kuhn and R. Bakke 
ADM1 with modifications for Bio-hydrogen Simulations The First International Workshop on the IWA Anaerobic Digestion Model No. 1 (ADM1), Sep 2-4, 2005, Lyngby, Denmark.

Deshai Botheju., Rathnasiri P.G. and Bakke R. 
Biofilms on oxygen transfer membranes in membrane micro-aerated anaerobic digesters (MMAD). IWA Biofilm Technologies Conferences, Singapore, 8-10, January 2008.

International Journals

Rathnasiri and Maganr Ottøy
Oxygen transfer and transport resistance across silicone tubular membranes. HIT.Publication 8/2003, ISSN 1503-3767(online)

b. K.K.C.K. Perera, P.G. Rathnasiri, S.A.S. Senarath, A.G.T. Sugathapala,_, S.C. Bhattacharya, P. Abdul Salam
Assessment of sustainable energy potential of non-plantation biomass resources in Sri Lanka. Biomass and Bioenergy 29 (2005) 199–213

c. S.C. Bhattacharya,_, P. Abdul Salam, Hu Runqing, H.I. Somashekar, D.A. Racelis, P.G. Rathnasiri, Rungrawe Yingyuad

An assessment of the potential for non-plantation biomass resources in selected Asian countries for 2010. Biomass and Bioenergy 29 (2005) 153–166

d. K.K.C.K. Perera, P.G. Rathnasiri, A.G.T. Sugathapala
Sustainable biomass production for energy in Sri Lanka Biomass and Bioenergy 25 (2003) 541 – 556

e. B.R.H. Peiris, P.G. Rathnasiri, J.E. Johansen, A. Kuhn and R. Bakke 
ADM1 simulations of hydrogen production Water Science & Technology, Vol 53 (2006), No 8 pp 129–137


 Services for the Industry 

Process modifications

Applications of CFD to improve efficiency of processes

Waste treatment


Ongoing Industrial Projects

Development of green process and factory building for Browns ltd. Ratmalana

Design of fine particle recovery system for Lion brewery