Relationship between Pressure Drop and H2S Elimination Capacity and Mass Loading Rates in Bifiltration Using Activated Sludge and Mixed Activated Sludge and Rice Husk Silica

In recent years researchers have shown that increasing in pressure drop and low amount of elimination capacity are two main limitations of biofiltration systems in pollutants treatment. Therefore, the main goal of this study was to investigate the relationship between pressure drop and hydrogen sulfide (H2S) elimination capacity with different mass loading rates in biofiltration system using activated sludge and mixed activated sludge and rice husk silica as packing materials. Two poly vinyl chloride (PVC) filters with one liter of prepared bed were tested for each filter. Dried activated sludge was collected from Putrajaya sewage treatment plant in Malaysia. The system was tested from different empty bed residence time (EBRT) from 30 to 90 sec and different H2S mass loading rate from 18.36 to 54 gm-3h-1. Based on the statistical analysis of Pearson correlation, there was a direct and very high relationship between the increasing hydrogen sulfide mass loading rate and the amount of pressure drop in the both packed filters (p<0.01). Also, with the H2S mass loading rate of 54 gm-3h-1 and EBRT of 30 s, the maximum elimination capacity was obtained in the activated sludge and mixed rice husk silica with dried activated sludge packed filters up to 52.32 and 44.33, respectively. Moreover, based on the statistical analysis of the Pearson correlation, there was a direct and very high corelatior between the increasing H2S mass loading rate and the amount of pressure drop in the both filters (p<0.01). After 53 days of operating time and 54 gm-3h-1 of mass loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O) for the mixed rice husk silica with dried activated sludge packed and dried activated sludge packed filters, respectively. Based on the results of the study, there is a direct and positive relationship between the increasing H2S mass loading rate and the amount of pressure drop and elimination capacity in both filters, but mixed rice husk silica with dried activated sludge showed higher elimination capacity and lower pressure drop.