International Journal of Engineering and Technology Innovation, vol . 3, no. 1, 2013, pp. 10-19 Sensitivity Analysis of Population in The Generation of Hazardous and Non-Harzardous Wastes, and Gas from Dumpsites of Ogbomosoland in Nigeria Samson O. Ojoawo 1,* , Oluwole A. Agbede 2 and Abimbola Y. Sangodoyin 3 1 Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria 2 Department of Civil Engineering, University of Ibadan,Ibadan, Nigeria 3 Department of Agricultural and Environmental Engineering, University of Ibadan, Ibadan, Nigeria Received 12 October 2012; received in revised form 15 November 2012; accepted 04 December 2012 Abstract This paper applies the principles of system dynamics modeling in studying the pattern of population changes and the corresponding non-hazardous wastes and gas being generated from the dumpsites of Ogbomosoland, Nigeria. The five (5) Local government Areas (LGAs) of Ogbomosoland were categorized as Urban (Ogbomoso North and Ogbomoso South) and Rural (Oriire, Ogo Oluwa and Suurulere) based on the size, population of residents, consumption pattern and socio-economic activities of the area. A sensitivity analysis of the simulated variables i.e the population, wastes and gas, was performed by employing the developed model results. Findings showed that the wastes and gas increased with the increased population in the 1000 years period. Also, gas production exceeds wastes generation rates for the rural LGAs in all cases. After a 25 years benchmark, when the simulated population of the urban and rural LGAs are respectively 303,411 and 344,735, the rates of waste generation are 3.33x10 6 and 6.22 x10 6 m 3 , while the corresponding rates of gas production is 2.44x10 3 and 6.47x10 3 m 3 in same order. The study concludes that wastes and gas generation from dumpsites are highly sensitive to population growth. It also concluded that the rate of gas generation is higher in organic wastes of the rural LGAs. The maximum population permissible in the model is 300,000 thus design of full-fledge landfills is recommended to replace the existing dumpsites in the study area. Keywords: system dynamics, sensitivity analysis, population, non-hazardous wastes 1. Introduction Non-hazardous wastes are composed of different materials or commodities and constitute a major portion of the Municipal solid wastes (MSW). They are not simply trash; however, they cover components of the MSW with valuable commodities such as paper, cardboard, aluminum, steel, and energy [1]. An integrated waste management system considers fluctuating recycling markets, energy potential, and long-term landfill cost and capacity to make a waste management strategy that is sustainable. Waste generation increases with population expansion and economic development [2]. Improperly managed solid waste poses a risk to human health and the environment. Uncontrolled dumping and improper waste handling causes a variety of problems, including contaminating water, attracting insects and rodents, and increasing flooding due to blocked drainage canals or gullies. The amount of wastes produced is influenced by economic activity, consumption, and population * Corresponding author. E-mail address: soojoawo@lautech.edu.ng Tel.: +234-803-391-6883