Quest Journals Journal of Architecture and Civil Engineering Volume 6 ~ Issue 12 (2021) pp: 45-53 www.questjournals.org *Corresponding Author: Arimieari, L.W. 45 | Page Research Paper Modelling of Chemical Contaminant Transport of Open Dumpsite Leachate on Groundwater using MATLAB Program Arimieari, L.W. 1* , Egop,S.E. 2 1, 2 Civil EngineeringDepartment, Rivers State University, Port Harcourt, Nigeria. *Corresponding Author: Arimieari, L.W. ABSTRACT: The research models and simulates the chemical contaminants transport of open dumpsite leachate on groundwater quality surrounding the study area ofOyigbo Local Government Area in Rivers State, Nigeria. Chemical analysis assessmentswere conducted on the groundwater samples collected from three (3) boreholes. The chemical parameters tested include the Nitrates (NO 3 2- ), Chlorides (Cl - ) and Sulphates (SO 4 2- ) ionswhich inadvertently contaminate the groundwater quality through the formation of leachates from the dumpsite. This environmental impact on the groundwater quality of leachate contamination of the dumpsite at Oyigbo Local Government Area was simulated. The MATLAB programming language was deployed in modelling the transport of the chemical contaminants in the groundwater. The simulated model demystify that the contaminants diffuses profusely through the porous media and the model elucidates that the concentration of the chemical contaminants diminishes as they travel and spread out downstream of the landfill to an insignificant concentration level at about 50 metres from the source point of the plume. KEYWORDS: Leachate, Groundwater Contaminant Transport, MATLAB Program Received 08 Dec, 2021; Revised 21 Dec, 2021; Accepted 23 Dec, 2021 © The author(s) 2021. Published with open access at www.questjournals.org I. INTRODUCTION The devastation of waste disposal in municipal communities has become uncontrollably alarming. Solid wastes are disposed on the land surface causing potential sources ofgroundwater contamination [1]. The objective in this paper is to develop mathematical modelthat describes the transport in the subsurface of contaminants dissolvedin the groundwater that occupies the void space, or part of it. The impact of leachates on groundwater and other water sources has become a global predicament due to its overwhelming environmental significance. Leachate transport from waste dumpsites or landfill areas and the release of pollutants from sediment poses a high risk to groundwater if not effectively and properly managed [1]. Leachates are liquids produced that when water has been dissolved and percolated or infiltrated through the solid wastes as well as by the squeezing of the waste due to self-weight. Water that penetrates into landfill picks up the soluble constituents from the wastes and may enter either the ground water or the surface water and thus act as a vehicle carrying potentially toxic matter from the landfill to the water sources. The important factors that influence leachate quality are waste composition, elapsed time, temperature, moisture and available oxygen. In general, leachate quality of the same waste type may be different in landfills located in different climatic regions. The physicochemical concentration was tested from the collected groundwater samples. The effect of depth and distance of landfill from groundwater were studied and remedial measures were suggested to avoid future contamination by leachate percolation[2]. One prevailing crisis faced in the urban and industrial areas predominantly in the developing countries is the solid waste disposal and management which deteriorates the environmental ecosystems. Enormous amount of solid waste are generated on daily basis and its management becomes a huge task. Solid waste generation has stimulated an increasing trend parallel to the development of industrialization, urbanization and rapid growth of population. The solid waste management encompasses from the collection, transportation and disposal of waste. In recent times, the management of solid waste necessitates transporting the waste from founded areas to distant places for dumping without any measure of dealing away with the waste, leaving nature to take its course. However, today, the increasing land value, inadequate space, limited capacity of nature to