Bacteria cells in gravel and water
Gravel samples (about 5 g each) were resuspended in 50 mL sodium sodium pyrophosphate solution (0.2 %, wt/vol) and sonicated for 10 min. After sedimentation for 30 min at room temperature, the samples were immediately diluted in sterile saline solution (0.85% NaCl solu tion, wt/vol) and inoculated in triplicate onto plate count agar (pour
plate method). These were incubated at 35oC for 48 h and then the numbers of forming colony were counted (APHA AWWA WPCF,
1998). The forming colony from the gravel samples were counted as