STUDIES ON COLIFORM REMOVAL EFFICIENCY IN ASP

Abstract

Activated Sludge Process is the most generally applied biological wastewater treatment method for reducing organic matter, suspended solids and nutrients in an efficient mean. This study evaluated the removal of total coliforms (TC), fecal coliforms (FC) and fecal streptococci (FS) in Activated Sludge Process and Extended Aeratiion Process functioning at full scale system in the tropical climate of Hardwar, and Delhi. Sampling points are raw sewage and effluent from the treatment plants. In ASP, Kankhal the average value of BOD, COD, TSS and Turbidity was observed as 138.53 mg/L, 278.79mg/L, 320.65 mg/L and 113 mg/L respectively. The average value of BOD, COD, TSS and Turbidity concentration in effluent was observed as 16.45 mg/L, 37.65 mg/L, 16.41 mg/L, 2.8mg/L respectively. TC, FC and FS concentrations in the system influent were 3.64 x 108 MPN/100mL, 6.54 x 107 MPN/100mL and 5.73 x106 MPNI100mL. Observations revealed that the effluent concentrations of TC, FC and FS were 3.75 x 105, MPN/100mL, 1.84 x 105MPN/100mL and 1.25 x 104 MPN /100mL. In EA, Vasant Kunj the average value of BOD, COD, TSS and Turbidity was observed as 263.75 mg/L, 622.8 mg/L , 392.625 mg/L and 332 mg/L respectively. The average value of BOD, COD, TSS and Turbidity concentration in effluent was observed as 24.44 mg/L, 70.20 mg/L, 78.48 mg/L and 11.2 mg/L respectively. TC, FC and FS concentrations in the system influent were 5.07 x IC MPN/100mL, 2.14 x 107 MPN/100mL and 3.57 x 105 MPN/100mL. Observations revealed that the effluent concentrations of TC, FC and FS were 1.67 x 104MPN/100mL, 1.2 x 104MPN/100mL, 8.94 x 102 MPN/I00mL. Effluent turbidity and BOD had a good correlation with the effluent concentrations of indicator microorganisms in ASP, Kankhal (nearly r2 is 0.7). But, in EA, Vasant Kunj, physico-chemical parameters didn't have good correlation with effluent concentrations of indicator microorganisms (nearly ? is 0.2 - 0.6) Similarly, operating parameters like MLSS, SVI and P/M showed a good correlation with effluent concentrations of indicator microorganisms. It has been observed from these two plants that protozoan community could be a good indicator of effluent quality.