Magister Scientiae - MSc (Biotechnology) / The treatment of mine water at the eMalahleni Water Reclamation Plant (EWRP) results in the production of large volumes of brine. Different brine management methods have been applied to dispose the brine but the evaporation pond method is regarded as the cheaper, most effective and less laborious method for brine disposal. Brine wastewater is pumped into the pond where it evaporates resulting in the mixture of salts. The rate at which evaporation occurs is influenced by many factors such as temperature, salinity, humidity and wind. Due to high salinities in brine the EWRP is currently experiencing a challenge with low evaporation rate. Here, a comparative study was done to determine the efficiency of using a chemical and a biological approach to enhance the evaporation rate of reject brine. The chemical approach involved the addition of various concentrations of methylene blue dye (100 to 300 ppm with 50 ppm increments) to 1L volumes of brine, and measuring the evaporation rate. On the other hand, the biological approach involved the isolation of pigmented halophilic bacteria from eMalahleni brine and Cerebos salt samples. Isolated bacterial strains were characterised based on their morphology, biochemical and salt tolerance characteristics. Furthermore, the strains were identified using 16S rRNA gene sequence analysis. Among the isolated halophilic bacterial strains, EP-3, an Arthobacter agilis isolated from the eMalahleni brine produced a darker pigment compared to the other strains. Therefore, EP-3 was evaluated for its effect on the evaporation of brine using a culture inoculum or the addition pigment extracted from an EP-3 culture. The addition of MB above 100 ppm overcame the effect of salt precipitation and resulted in higher evaporation (41%) rate. Addition of pigmented bacteria or bacterial extracted pigment to the brine respectively resulted in 18% and 24% increase in the evaporation rate.

This thesis is a study of naturally occurring radioactive materials (NORM) activity concentration, gamma dose rate and radon (222Rn) exhalation from the waste streams of large-scale onshore petroleum operations. Types of activities covered included; sludge recovery from separation tanks, sludge farming, NORM storage, scaling in oil tubulars, scaling in gas production and sedimentation in produced water evaporation ponds. Field work was conducted in the arid desert terrain of an operational oil exploration and production region in the Sultanate of Oman. The main radionuclides found were 226Ra and 210Pb (238U - series), 228Ra and 228Th (232Th - series), and 227Ac (235U - series), along with 40K. All activity concentrations were higher than the ambient soil level and varied over several orders of magnitude. The range of gamma dose rates at a 1 m height above ground for the farm treated sludge had a range of 0.06 0.43 µSv h 1, and an average close to the ambient soil mean of 0.086 ± 0.014 µSv h 1, whereas the untreated sludge gamma dose rates had a range of 0.07 1.78 µSv h 1, and a mean of 0.456 ± 0.303 µSv h 1. The geometric mean of ambient soil 222Rn exhalation rate for area surrounding the sludge was mBq m 2 s 1. Radon exhalation rates reported in oil waste products were all higher than the ambient soil value and varied over three orders of magnitude. This study resulted in some unique findings including: (i) detection of radiotoxic 227Ac in the oil scales and sludge, (ii) need of a new empirical relation between petroleum sludge activity concentrations and gamma dose rates, and (iii) assessment of exhalation of 222Rn from oil sludge. Additionally the study investigated a method to determine oil scale and sludge age by the use of inherent behaviour of radionuclides as 228Ra:226Ra and 228Th:228Ra activity ratios.