Changes in pH and Bacterial Populations in Sewage Sludge and Mixture of Sewage Sludge With Rice Husk Silica to Remove H2S Pollution

Abstract

the performance of the filters was evaluated during the start-up period at a constant empty bed residence time (EBRT) of 60 seconds and different inlet concentrations of H2S ranging from 10 to 300 ppm. In the second stage, the flow rate (L/min) was variable with different EBRTs ranging from 30 to 90 seconds and the concentration of H2S was fixed at 300 ppm. Results: In this study, after 53 days of operating time and 54 g/m 3 h mass loading, the pH values in the SS and MSSRHS packed filters were reduced from 6.8 to 1.8 and from 6.9 to 3.4, respectively. The MSSRHS packed filter showed more buffering capacity to resist pH changes. Therefore, in this packed filter, both sulfur bacteria, namely, Thiobacillus thioparus and Thiobacillus thiooxidans, could grow and oxidize H 2 S better than SS packed filter could. These are very important in maintaining microorganisms’ activity for long-term biofilter operation to remove air pollutants. Conclusions: The MSSRHS could be considered as a more suitable packing material for long-term biofilter operation to remove H 2 S pollution.