Abstract The adsorption behavior of Methylene blue dye, Bismarck brown Y dye, and Indigo dye on to Sphagnum cymbifolium (moss) was investigated as a function of flow rate, and bed height through the fixed bed process. OBJECTIVES: One of the main objectives of this research is to expand the field of application of natural biomass for the treatment of dye waste waters from industrial effluents. Additionally, it is aimed at elucidating the dependency or otherwise of flow rate, and bed height using the fixed bed technique method of adsorption. METHODS: The biomass was characterized by Scanning Electron Microscopy (SEM) in order to examine the morphology of the biomass. The screened biomass samples were characterized at 1000 x magnification, and 500 x magnification respectively for their surface morphologies. This was done using a scanning electron microscope (FEI – Inspect/OXFORD INSTRUMENTS - X – MAX) which was equipped with an energy dispersive x-ray (EDAX) spectrophotometer employed for the elemental composition analyses. It was equally characterized with Fourier Transformed Infrared Spectroscopy (FTIR) before and after adsorption to ascertain the functional groups responsible for the adsorption. This was done using a Fourier Transformed Infrared (FTIR) Spectrophotometer (Perkin-Elmer, England) in the wavelength range of 350 – 4000nm. RESULTS: Results for the biomass morphology obtained through the Scanning Electron Microscopy (SEM) revealed the presence of tiny pores. These pores represent sites where dye molecules could be trapped in the course of the adsorption. The result from the Fourier Transformed Infrared Spectroscopy (FTIR) after adsorption show that C-H, C?H, C?C functional groups were responsible for the adsorption. For methylene blue dye, at the flow rate of 20m3/s, the amount of dye adsorbed was 18.80mg/g, 22.70mg/g at 30m3/s, and 25.40mg/g at 40m3/s. For Bismarck brown Y dye, at the same range of flow rate, the amount of dye adsorbed ranged from 12.34mg/g – 20.62mg/g. For indigo dye, the values obtained ranged from 6.48mg/g – 17.71mg/g. In addition, at the bed height range of 4.0 – 6.0x10-2(m), the amount of dye adsorbed ranged from 6.31mg/g – 27.73mg/g for methylene blue dye. Within the same range of bed height, the amount of dye adsorbed ranged from 16.40mg/g – 25.60mg/g for Bismarck brown y dye, and 12.57mg/g – 17.71mg/g for indigo dye. CONCLUSION: From the above result, it is evident that methylene blue dye was the most adsorbed, while indigo dye was the least adsorbed within the same experimental considerations. In addition, the three different dyes can adsorb on to Sphagnum cymbifolium (moss) at various degrees. Also, the amount of dye adsorbed is dependent on the flow rate and bed height within the range of experimental consideration. In each of the analyses, three different experiments were performed, and the mean values reported with their standard deviations.