Research Article
Aka Chidike Kanu, Akuma Oji
Abstract
Oil and grease, temperature, pH, and heavy metal concentrations are some of the main quality parameters used in the regulation of the discharge of oil and gas field produced water to the environment. The use of cheap biological plant materials to selectively remove heavy metals from aqueous solutions is considered a potentially viable alternative to expensive ion-exchange resins and semi-permeable membranes. However, a key requirement for the efficient and cost-effective application of biosorption systems to industrial-scale wastewater treatment is the ability to regenerate and reuse biological sorbents used for the ion uptake. This paper presents a case study of the application of biosorption to sample produced water from an oil field in the Niger Delta. The produced water was characterised for both heavy metal concentration and other quality indices. Using batch adsorption system, with raw and pre-treated sawdust as adsorbent, uptake of heavy metal ions was investigated. The analyses indicated that the sorbent samples have significant sorption capacity for heavy metal ions. Applying classical equilibrium sorption model and theory, it was observed that metal ion affinity as a function of reversibility of adsorption, was very sensitive to biosorbent pre-treatment used. Based on this case study, a cheap and simple process for the tertiary treatment of produced water is proposed. Further investigation is envisaged in the area of continuous-flow system modelling and optimisation.