Enhancing Sustainable Oil and Gas Operations: Produced Water Treatment Using Biological Oxidation

Abstract In navigating the imperative of sustainable practices, the oil and gas industry faces a growing need for efficient and environmentally conscious produced water management. Challenges in produced water disposal encompass regulatory compliance, environmental considerations, induced seismicity risks, and the pursuit of economically sustainable solutions. There is a compelling need to explore efficient treatment methods that encourage the reuse of produced water while simultaneously providing long-term storage solutions to alleviate the strain on freshwater resources. Biological oxidation, employing microorganisms to metabolize organic pollutants, has emerged as a promising and sustainable approach for produced water treatment. Applied at the secondary treatment stage, this technology significantly reduces contaminant and suspended solid concentrations post-primary treatment in the tank battery. The aim of this treatment method is to decrease the biological load in the produced water by introducing facultative microbes that prevent the pit from souring and halting H2S production. Additionally, aeration of the produced water impoundment is essential to introduce dissolved oxygen (DO) and enhance the performance of robust microbial strains. The introduction of aeration proved instrumental in enhancing produced water treatment, facilitating the efficient dispersion of chemical amendments within impoundments through enhanced recirculation and mixing. Biological oxidation treatment resulted in below detection levels (BDL) of H2S, and post-treatment analysis revealed the absence of sulfate-reducing bacteria (SRB) activity, preventing souring in saltwater disposal (SWD) compared to conventional biocide or flop and drop treatments. Key indicators, such as dissolved oxygen and oxygen reduction potential (ORP), crucial for water stabilization, remained consistently stable over a six-month period without requiring further intervention. The introduced biological oxidation process represents a cost-effective solution for treating produced water from diverse oil and gas extraction operations. A notable advantage is the absence of chemical or polymer sludge residue in the water impoundments, contributing to a cleaner treatment outcome. Beyond immediate benefits, biological oxidation plays a pivotal role in achieving long-term stabilization, fostering an efficient reuse program, and presenting a viable alternative to conventional water disposal methods.