Modelling Cow-Dung and Grass- Clippings Isothermal Continuous Stirred Co-digester for Biogas Production using Modified Gompertz Rate Equation


  •   Millionaire Freeborn Nestor Abowei

  •   A. C. Akinwande

  •   J. G. Akpa


The continuous search in renewable energy sources for industrial and domestic utilization is very imperative and motivated this study. The study of Cow- dung and grass clippings Co-digestion are important due to the fact that successful outcome of the studies will provide a basis for waste minimization and enhance renewable energy production for global consumption. This work therefore is focused by exploiting the modified Gompertz kinetic equation in developing design models for the simulation of continuous stirred  co-digester(CSC) at isothermal condition. Co-digester functional dimensions such as volume, length, space time, space velocity and heat generation per unit volume were developed for Continuous Stirred Co-digester type..The developed models were simulated using Matlab codes programming technique using design basis of 50,000 metric tons of biogas per annum at 37oC isothermal condition. The developed performance models were solved numerically using MATLAB version 7.1 within the operational limit of conversion degree, XA = 0.1 to 0.9.The results obtained showed that increase in fractional dimensions of Co-digester volume VR, length LR and Space time S increases with increase in fractional conversion at constant radius.  Results of space velocity (S) and heat generation/per unit volume (q) showed inverse characteristic behavior as increase in fractional conversion decreases space velocity and heat generation per unit volumes.. Further careful examination of the results, demonstrated that at optimal yield of 0.9 degree of conversion, Co-digester volume value of 10.0m3 at constant radius was feasible. The results as obtained in this work proved dependable relationship with fractional conversion.


Keywords: Modelling, Isothermal, Grass-Clipping, Cow-Dung Continuous Stirred, Co-Digester, Gompertz Rate Equation


Abdulsalam, S. & Yusuf, M. (2015). A Kinetic Study of Biogas Produced from Cow and Elephant Dungs using Residual Substrate Concentration Approach. Chemical Engineering and Science, 3(1), 7 – 11.

Abowei M.F.N & Goodhead T.O “Modeling of Isothermal CSTR Adsorption Tower for Sulphur Trioxide Hydration Using Vanadium Catalyst” Int’l Journal of Modern Engineering Science, 2014, 3(1): 39-60 (ISSN:2167-1133).

Ali kasap, Ramazam Aktas, Emre Dulger.(2012). Journal of Agricultural Machinery Science, 8(3), 271-277.

Allan, H. (1998). Grass Productivity. Island Press Conservation Classics Series, Washington DC.

Angelidaki, I. (1996). The Biogas Process: Energy from Biomass (6362).

Angelidaki I, Ellegard L, & Ahring B.K. (2003). Application of the anaerobic digestion process. Adv Biochem Eng Biotechnol. (82), 1-33

Anthony, N.M., Mohammed, B., Tumisang, S. and Catherine, J. (2015). The Kinetic of Biogas Rate from Cow-Dung and Grass Clippings.

Igoni, A.H. & Harry, I.S.K. (2017). Design Models for Anaerobic Batch Digesters Producing Biogas from Municipal Solid Waste. InternationalJournal of Biogas, 19(2), 11 – 19.

Etuwe, C.N., Momoh, Y.O.L. & Iyagba, E.T. (2016). Development of Mathematical Models and Application of the Modified Gompertz Model for Designing Batch Biogas Reactors. Springer Science and Business Media Dordrecht, 315 – 326.

Igoni A.H., Abowei M.F.N., Ayotamuno M.J., & Eze C.L. (2008). Effect of Total Solids Concentration of Municipal Solid Waste on the Biogas produced in an Anaerobic Continuous Digester. Agricultural Engineering International: the CIGR Ejournal, X:7-10.

John, B.B. (2007). Reactor design and reactor kinetics engineering. 5th edition, Butter-worth-Heinemann.

Lastella, G., Testa, C., Cornacchia, G., Notomicola, M., Voltasio, F. & Sharma, V.K. (2002). Anaerobic Digestion of Semi Solid Organic Waste Biogas Production and its Purification pdf. Energy Conservation and Management, 43.

Latinwo, G.K. & Agarry, S.E. (2015). Modelling the kinetics of Biogas Production from Mesophilic Anaerobic Co-Digestion of Cow Dung with Plantain Peels. International Journal of Renewable Energy Development, 4(1), 55 – 63.

Matheri, A.N. (2015). Analysis of the Biogas Productivity from Dry Fermentation of Organic Fraction of Municipal Solid Waste.

Matheri, A.N., Belaid, M., Seodigeng, T. & Ngila J.C. (2016). The Role of Trace Elements on Anaerobic Co-digestion in Biogas Production. In Proceedings of the World Congress on Engineering, London, U.K.

Matheri, A.N., Belaid, M., Seodigeng, T. & Ngila, C.J. (2015). The Kinetic of Biogas Rate from Cow Dung and Grass Clippings. International Conference on Latest Trends in Engineering and Technology, 26 – 27.

Matheri, A.N., Ndiweni, S.N., Belaid, M., Muzenda, E. & Hubert, R. (2017). Optimizing Biogas Production from Anaerobic Co-digestion of chicken Manure and Organic Fraction of Municipal Solid Waste. Renewal and Sustainable Energy Review, 80, 756 – 764.

Monnet, F. (2003). An Introduction to Anaerobic Digestion of Organic Waste, Industrial to anaerobic digestion November 2003. Pdf (27th November, 2017).

Omer, T.O. & Fedalla, M.O. (2002). Engineering Design and Economic Evaluation of a Family-Sized Biogas Project in Nigeria. Technovation, 12 – 15.

Ostream, K. (2004). Green Waste; Anaerobic Digestion for Treating the Organic Fraction of Municipal Solid Wastes. Unpublished M.Sc Thesis in Earth Resources Engineering Department of Earth and Environmental Engineering Foundation of School of Engineering and Applied Science, Columbia University.

Perry, H.R. & Green, W.D. (2008). Perry’s Chemical Engineering Handbook. 8th Edition. New York: McGraw-Hill Publishers.

Pesta, G. (2007). Anaerobic Digestion of Organic Residues and Wastes. In: Oreopoulou V., Russ, W. Editors. Utilization of By-products and Treatment of Waste in the Food Industry. New York: Spinger, 53 – 73.

Sinnott, R. & Towler, G. (2009). Chemical engineering design.5th edition. Butter-worth-Heinemann.

Sreekrishnan, T.R., Kohli, S. & Rana, V. (2004). Enhancement of Biogas Production from Solid Substrates using Different Techniques – a Review. Bioresource Technology, 95(1) 1 – 10.

Themelis, N.J. and Verma, S. (2004). The Better Option: Anaerobic Digestion of Organic Waste in MSW. Waste Management World January/February 2004. (27th November, 2018).


Download data is not yet available.


How to Cite
Abowei, M., Akinwande, A. and Akpa, J. 2019. Modelling Cow-Dung and Grass- Clippings Isothermal Continuous Stirred Co-digester for Biogas Production using Modified Gompertz Rate Equation. European Journal of Engineering and Technology Research. 4, 3 (Apr. 2019), 196-202. DOI: