Abstract:
This research objective was to improve the operation and control for activated sludge process of Navanakorn Industrial Estate by determining kinetic parameters of biological aerobic degradation of both soluble and nonsoluble organics. Also, a computer model imitating real wastewater treatment process was constructed. This research contents were divided into two steps as follow. First step included the determination of ïm, KS, YH, and bH for soluble organics (sCOD) and microbial sludge, and determination of kd for influent suspended solids. Experiments were performed separately using concentrations of real wastewater 25 - 300 mg COD/L, boiled wastewater 30 - 900 mg COD/L, microbial sludge 4,000 mg cellCOD/L, and influent suspended solids 8,000 and 12,000 mg COD/L. Kinetic parameters were analyzed using non-linear Monod equation by SPSS and AQUASIM programs. Ratio of nbCOD/TCOD of wastewater, influent solids, and microbial sludge were also determined. Results from sCOD analysis found that nbCOD/TCOD, ïm, and KS of real wastewater were 0.363 ï± 0.025, 9.92 ï± 1.91 d-1, and 88.9 ï± 38.5 mg/L, respectively. For boiled wastewater were 0.374 ï± 0.008, 4.43 ï± 0.325 d-1, and 47.5 ï± 13.1 mg/L, respectively. Yield (YH) was 0.620 ï± 0.038 mg cellCOD/mg-COD. Results from influent solids analysis found that nbCOD/TCOD, kd, and COD/MLSS were 0.752 ï± 0.009, 0.907 ï± 0.090 d-1, and 1.52 ï± 0.013, respectively. And results from microbial sludge analysis found that nbCOD/TCOD, bH, and COD/MLSS were 0.862 ï± 0.025, 0.176 ï± 0.061 d-1, and 0.756 ï± 0.005, respectively. Second step was the construction of computer model of Navanakorn wastewater treatment process by AQUASIM. Kinetic parameters from first step and real operation conditions from Navanakorn were applied in the computer model. Data of COD and MLSS between real data from Navanakorn reports and this computer model were compared. Results were found that most of effluent TCOD (99%) was nondegradable (nbCOD) and 66% of sludge in aeration tank was inert. These founded kinetic parameters can be used to improve the operation and control of this wastewater treatment plant.