Radioactivity in Oily Sludge and Produced Waste Water from Oil: Environmental Concerns and Potential Remedial Measures

Abstract

Produced water separated from oil is usually returned to the environment and could permeate through the water table. If such water is contaminated with radioactive substances, it could create a definite threat to the water supply, especially in arid regions where ground water and overhead streams are sources of potable water. Low-level radioactive contamination of oily sludge is equally hazardous and also leads to detrimental pollution of water resources. We investigated the distribution of 226Ra, 40K and 228Ac in produced waste water and oily sludge and found abnormal levels of radioactivity. A total of 90 ground wastewater samples were collected from different sites for a period of one year. The presence of these radionuclides was identified by their characteristic gamma rays. The detection system consisted of a high-purity germanium detector. Our results show that about 20% of the samples exhibited 20–60 Bq/L radioactivity and ~6% of the samples exceeded 60 Bq/L. Roughly 70% of the experimental samples fell in the range of 2–20 Bq/L, which still exceeded the maximum admissible drinking-water limit 0.2 Bq/L

Concentrations of TENORMs in the petroleum industry and their environmental and health effects

“…232,[245][246][247][248] Impact on surface water. 8,138,225,249 All effluents from the oil and gas industry such as produced water, washing water for rigs, drilling machines, maintenance and repair, oil grease contaminated water, liquid sludge, etc., may contain radioactive materials. Consequently, discharging into the environment and lead to the release of these materials into the surface of the earth and may cause unexpected damage due to increase the concentrations of radioactive materials by leakage to subsurface water.…”

“…Therefore, the external radiation dose and associated risks in the vicinity of oil and gas facilities increases as sludge builds up. 138,191 Sludge may be classied as hazardous wastes (more than the solid wastes) because it is oen in liquid form, so when disposed of, it always seeps through the soil and gradually pollutes groundwater and shallow groundwater.…”

UN World Water Development Report 2017: "Wastewater: The untapped resource"

“…Oman tested the treatment and use of oil-containing wastewater for irrigation as an alternative to injecting the water back into aquifers, contaminating groundwater resources (JPEC, 1999). The de-oiling of produced water was also researched by Sultan Qaboos University in Oman (Pillay et al, 2010), which found that constructed wetlands could also be used to dispose of the treated produced water.…”