Journal of Geography, Environment and Earth Science International

Abattoir wastewater contains nitrate concentration, which is toxic to the environment when discharged without treatment, adsorption is one of the effective methods for removal of nitrate in abattoir wastewater. The aim of this research work is to study the kinetics of nitrate removal in a packed bed column. The effluent from a waste water treatment plant was treated with crushed bone activated carbon (CBAC) in a packed bed and the adsorption performance of the packed bed for the removal of nitrate was investigated by varying various parameters such as pH, bed heights and particle size. The results indicate that the adsorption efficiency increased from 67.44% to 88.82% with increase in pH from 2 to 12, increased from 95.57% to 97.08% with increase in bed height from 10 to 30 cm and decreased from 95.58% to 90.54% with increase in particle size from 850 to 450 µm. The adsorption kinetics was analyzed using Thomas and Yoon-Nelson kinetic models. For bed heights of 10, 20 and 30 cm analyzed using Yoon-nelson model, adsorption time τ was 381.16, 428 and 464.34 min^-1 respectively and Yoon-Nelson constant K_YN was 0.0037, 0.0036 and 0.0035 min^-1 respectively, indicating that as bed height increased, τ increased and K_YN decreased. For Thomas model where bed heights of 10, 20 and 30 cm were used maximum adsorption capacity q₀ was 311.66, 174.84 and 126.57 mg/g respectively and Thomas constant K_TH was 0.0037, 0.0036 and 0.0035 respectively, indicating that as bed height increased q₀ and K_TH decreased.