Application of a Thermophilic aerobic digestion process to industrial waste activated sludge treatment

The performance of six strains of thermophilic aerobic bacteria in enhancing the efficiency of thermophilic aerobic digestion of industrial waste activated sludge (WAS) was evaluated in a laboratory-scale experiment. The WAS had been collected from an oil refinery wastewater treatment plant in Korea. Digestion efficiency was assessed by measuring decreases in total suspended solids, dissolved organic carbon, and total organic carbon. Among the three strains of Bacillus stearothermophilus and three strains of Thermus spp. tested, B. stearothermophilus ATCC 31197 performed best in the batch digestion experiments. The strain was also successfully used in an experiment employing a semi-continuous (fill-and-draw) process of thermophilic aerobic digestion to degrade the oil refinery WAS.