Reusing H2S-exhausted carbon as packing material for odor biofiltration

Area of Science:

• Environmental Engineering
• Biotechnology
• Wastewater Treatment

Background:

• Spent activated carbon from H2S adsorption poses an environmental challenge in wastewater treatment.
• Reutilizing this spent carbon as a carrier for sulfide-oxidizing bacteria in biofilters is explored.

Purpose of the Study:

• To evaluate the efficacy of exhausted carbon from different adsorption bed heights as a substrate for H2S biofiltration.
• To investigate the performance and recovery capabilities of biofilters using spent carbon.

Main Methods:

• Four lab-scale biofilters were packed with exhausted carbon from the top, middle, bottom, and a mixture of H2S adsorption beds.
• Performance was assessed based on startup time, bacteria immobilization, H2S removal efficiency (RE), and recovery after shock loads and shutdowns.
• Sulfur product analysis and characterization of activated carbon before and after biofiltration were conducted.

Main Results:

• Biofilters exhibited rapid startup (approx. 80 h) and effective immobilization of sulfide-oxidizing bacteria, with higher counts on bottom carbon.
• High H2S removal efficiency was maintained with rapid recovery (within 2 h) after spike loadings and shutdowns (within 5 h).
• Bottom carbon showed the fastest recovery after shutdown (1 h).

Conclusions:

• Exhausted carbon serves as a viable and cost-effective carrier for sulfide-oxidizing bacteria in H2S biofiltration.
• This approach presents an economical alternative to conventional odor biofiltration systems.
• Spent carbon reuse addresses environmental concerns associated with H2S adsorption processes.