Abstract:
This research studied the kinetic parameters of aerobic treatment of domestic wastewater in Thailand by using real influent wastewater at Nhong Kham wastewater treatment plant. Influent wastewater was added with non-fat milk to increase COD to the range of 10-200 mg/L. The experiments were performed with batch reactors. The results showed that biomass growth yield (Y) was 0.298 mg-cell-COD/mg-COD. The ratio of non-biodegradable COD to total COD was 0.259. Kinetic parameters were determined using a non-linear equation of the Monod and statistical program. The maximum specific growth rate (μm) was 8.77±1.73 per day and the half-saturation coefficient (Ks) was 15.81±4.79 mg/L. Kinetic parameters from this research were in the same range of previous studies. These kinetic parameters were modeled according to Nhong Kham wastewater treatment operating conditions using AQUASIM program. The model showed much lower effluent COD than measured data because non-biodegradable COD was not included in the program. The model showed comparable total suspended solids (MLSS), about 4,000 mg/L, but the active microbial cells were only 250-350 mg/L and the rest of 3,500-3,700 mg/L were the accumulated inlet suspended solids. The results showed that inlet suspended solids could be used to increase suspended solids concentration and therefore enhance the efficiency of clarifier. The model could be adapted to wastewater treatment process efficiency.