Removal of NH₃ and H₂S from odor causing tannery emissions using biological filters: Impact of operational strategy on the performance of a pilot-scale bio-filter

Area of Science:

• Environmental Engineering
• Industrial Microbiology
• Air Pollution Control

Background:

• Tanneries generate odorous gases, necessitating eco-friendly treatment methods.
• Limited research exists on bio-filter applications for tannery emission control.
• Hydrogen sulfide (H2S) and ammonia (NH3) are key pollutants requiring effective deodorization.

Purpose of the Study:

• To evaluate bio-filter performance for H2S and NH3 removal from tannery emissions.
• To identify optimal design parameters for scaling up bio-filter technology.
• To assess the impact of bedding material on deodorization efficiency.

Main Methods:

• Pilot-scale bio-filter studies using a synthetic gas mixture of H2S and NH3.
• Monitoring removal efficacy at various empty bed residence times and inlet concentrations.
• Microbial biodiversity analysis to identify dominant microorganisms.
• Design and commissioning of a full-scale bio-filter in an operational tannery.

Main Results:

• Achieved 90-99% removal efficacy for both NH3 and H2S at 55-second empty bed residence time.
• Inlet concentrations of 200-210 ppmV for NH3 and H2S were effectively treated.
• Microbial counts increased significantly, with dominance of Proteobacteria, Firmicutes, and Acinetobacter.
• Full-scale bio-filter demonstrated sustained removal efficiency of >99% over three years.

Conclusions:

• Bio-filters are a viable, eco-friendly solution for tannery emission deodorization.
• Successful scale-up from pilot to full-scale operation confirms technology effectiveness.
• The study provides crucial design parameters for industrial application of bio-filters in tanneries.