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

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.