Formatted Title
Thermal Desorption of Heavy Oil-Contaminated Soils in an Oil Field in South Sudan
Background/Objectives
More than 12.000 m3 of soil are contaminated with heavy oils coming from an oil field exploitation for more than 20 years in one of the different oil fields in South Sudan. Soil contamination in that area has a massive negative impact on nature and health of the neighboring resident due to potable water and fertile soil contamination. Consequently, the site is contaminated with C10-C40, mainly heavier fractions (C30-C40).
Approach/Activities
In response to this environmental challenge, an English environmental remediation company engaged Haemers Technologies to spearhead the decontamination efforts. In 2022, the first phase began with a small ex situ pilot of 200 m3.
Due to the remote location of the site, several changes in design were necessary for good operation of the contaminated soil ex situ treatment. The main change is linked to the impossibility to have concrete on site to cover the soil pile. The pilot phase was conducted to test different designs to optimize the treatment counting with the challenges of this remote site. One more pilot pile is planned to resolve the difficulties encountered during the first pilot pile. Afterwards, six (6) full-scale piles of 2000 m³ are planned.
Contaminated vapors are treated using reburn technology which consists of using the flame created to heat the soil in order to burn the contaminated hydrocarbon vapors. Throughout the treatment process, rigorous monitoring encompassed gas emissions and consumption, ground temperature, and pressure to maintain precise control over the installation.
Results/Lessons Learned
The project encompassed the treatment of 12.000 m³ of contaminated soils, with maximum average pollutant concentrations of up to 56.000 mg/kg d.m for C10-C40 and 25.000 on average. The pilot treatment spanned a duration of 50 days and resulted in a remarkable pollutant mass reduction exceeding 99.9%.
Numerous obstacles were faced while conducting operations in South Sudan. The rainy season rendered certain roads to the site impassable, resulting in delays due to the unavailability of materials or equipment. Additionally, communication was challenging in this remote location, making it difficult to make quick decisions in response to issues. Consequently, there was a need for adaptability in both the design and schedule to effectively address the highly contaminated soils. The accomplishment of this initial remediation pilot has paved the way for the project's ongoing progress. The commencement of full-scale operations is scheduled for January 2024, with subsequent results to be shared.