Removal of Hydrogen Sulfide by Physico‐Biological Filter Using Mixed Rice Husk Silica and Dried Activated Sludge

This study investigated the effectiveness of a new packing material, namely mixed rice husk silica with dried activated sludge for removing H 2 S. Dried sewage sludge was collected from Putrajaya sewage treatment plant in Malaysia. Rice husk silica was prepared at temperature of 800°C, after acid leaching and mixed with dried sewage sludge to be utilized in a polyvinyl chloride filter. The system was operated under variable conditions of two parameters, different inlet gas concentration and different inlet flow rate. H 2 S was passed through the filter with one liter of the packing material. More than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 90–45 s and 300 ppm inlet concentration was observed. However, the RE decreased to 96.87% with the EBRT of 30 s. The maximum elimination capacity (EC) of 52.32 g/m 3 /h was obtained with the RE of 96.87% and H 2 S mass loading rate of 54 g/m 3 /h, while at the RE of 99.96%, maximum EC was 26.99 g/m 3 /h with the H 2 S mass‐loading rate of 27 g/m 3 /h. A strong significant correlation between increasing of H 2 S mass loading rate and pressure drop was also detected ( p  < 0.01). Maximum pressure drop was 3.0 mm H 2 O after 53 days of operating time, the EBRT of 30 s, and 54 g/m 3 /h of H 2 S loading rate. These observations suggest that the mixture of rice husk silica with dried activated sludge is a suitable physico‐biological filter for H 2 S removal.