Hydrogen Sulfide (H2S) Removal Using Biofilter Media Made from Autoclaved Aerated Concrete (AAC)

Gaseous emissions from industries can be highly odorous and toxic when concentrations exceed the regulatory limits. To remove these gases, biofilters are commonly selected because of their simplicity in design, economic advantages, and ease of operation. Since biofilter packing media play a crucial role in biofilter performance, a novel biofilter medium using Autoclaved Aerated Concrete (AAC) is developed and tested in a pilot biofilter system in this work. AAC waste is abundant at construction sites and can be transformed into a value-added product, namely biofilter packing media. AAC is lightweight and has a high compressive strength and large surface area, which enhance the environment for biomass growth. In this study, a pilot biofilter system with AAC-based media was used to remove hydrogen sulfide (H2S) at a wastewater pumping station that emits H2S continuously. Performance data collected over a 5-month period show that AAC-based media can remove H2S at an empty bed residence time (EBRT) of only 5.5 s, with a removal efficiency (RE%) ranging from 95 to 100% for an average inlet concentration of 21.2 ± 0.1 ppm of H2S. Thus, industrial biofilters can be built in smaller units at lower capital cost, provided the concentration ranges meet these experimental conditions. This novel AAC-based medium can be a promising alternative to organic or currently available synthetic media for application in industrial biofilter systems.