Heavy Metals Removal From Spent Synthetic-Based Drilling Mud Using Nano Zero-Valent Iron (nZVI)

Obinduka Felix; Ify L. Nwaogazie; Onyewuchi Akaranta; Gideon O. Abu

Obinduka Felix Centre for Occupational Health, Safety and Engineering, University of Port-Harcourt, Nigeria.
Ify L. Nwaogazie Department of Civil and Environment Engineering, University of Port-Harcourt, Nigeria.
Onyewuchi Akaranta Centre of Excellence, Centre for Oilfield Chemicals Research, University of Port Harcourt, Port Harcourt, Nigeria.
Gideon O. Abu Department of Microbiology, University of Port Harcourt, Port Harcourt, Nigeria.

Keywords: Spent synthetic-based drilling mud, Niger Delta, heavy metals, Nano zero-valent Iron, mathematical model

Abstract

Management of waste generated from oil and gas activities in the Niger Delta, is a major environmental challenge given that if the spent mud is disposed without proper treatment, the heavy metals will pose a lot of health risks to human through ingestion or inhalation. The heavy metals are also toxic to marine organisms, if disposed into the sea, untreated. Spent synthetic drilling mud is a major waste stream, among its components, are heavy metals. Samples collected on day 0 and biweekly were digested and analysed using the atomic absorption spectrometer (AAS). With nano Zero-Valent Iron, nZVI, concentration of 0.75mg/L of the spent mud, more than 95% removal were recorded for most metals in 6 weeks and over 99% in 12 weeks. The residual heavy metal concentrations met global limits for effluent disposal. Mathematical models with the goodness of fit, R² of 0.999, were developed to predict the removal process.