H₂S Removal from Groundwater by Chemical Free Advanced Oxidation Process Using UV-C/VUV Radiation

Area of Science:

• Environmental Science
• Water Treatment Technology
• Photochemistry

Background:

• Hydrogen sulfide (H2S) contamination in groundwater causes odor and health issues.
• Conventional treatments for H2S often require chemical dosing and post-treatment.
• Advanced oxidation processes (AOPs) show promise but often lack in-situ radical generation.

Purpose of the Study:

• To investigate the efficacy of Vacuum-UV (VUV) based AOP for H2S removal from groundwater.
• To compare the performance of combined UV-C/VUV radiation versus UV-C only.
• To evaluate the treatment in both synthetic solutions and real groundwater under varying conditions.

Main Methods:

• Utilized a continuous-flow reactor system.
• Employed combined UV-C/VUV and UV-C only radiation sources.
• Analyzed H2S degradation, intermediate formation (sulfite), and final product (sulfate).
• Tested in deionized water and natural groundwater, including anoxic conditions.

Main Results:

• H2S degradation was significantly faster under combined UV-C/VUV radiation in deionized water, driven by indirect photolysis.
• Sulfite intermediates were observed, converting to sulfate at higher doses.
• Both UV-C/VUV and UV-C only effectively removed sulfide from natural groundwater.
• A slight advantage for combined UV-C/VUV was noted in anoxic groundwater conditions.

Conclusions:

• VUV-based AOP is a viable chemical-free method for H2S removal from groundwater.
• The technology is particularly suitable for remote or small-scale water treatment facilities.
• Further research can optimize VUV applications for efficient groundwater remediation.