In situ selenium removal via microbial reduction to se nanoparticles

Overview

The proposed solution offers a biological method to remediate selenium-contaminated groundwater by transforming soluble selenium oxyanions into insoluble elemental selenium (Se(0)) nanoparticles. This in situ treatment leverages the natural capabilities of selenium-reducing microorganisms to immobilize selenium effectively, thereby reducing its mobility and potential environmental impact. The process avoids the need for pump-and-treat systems, utilizing natural redox processes to achieve immobilization in the subsurface.

Technical specifications

Key Features:

• Utilizes selenium-reducing microorganisms or enzyme-rich biomass to convert selenite and selenate into elemental selenium.
• Targets groundwater-relevant conditions, optimizing factors like pH, ORP, and electron donor availability.
• Employs a four-stage validation approach, including synthetic groundwater tests, optimization of field variables, and porous-media column tests.
• Monitors selenium and arsenic mass balances, ensuring selenium immobilization without arsenic mobilization.

Technology readiness level

This technology is at Technology Readiness Level 3, indicating that it has been validated in a laboratory setting under controlled conditions. Further testing will involve moving from batch assays to more complex porous-media column tests to assess performance under flow conditions, particle retention, and treatment durability.