The application of moving bed-biofdm sequencing batch reactor system in decreasing Chemical Oxygen Demand (COD) concentration on palm sugar industry wastewater

Palm sugar wastewater has a high concentration of COD (3270-3773 mg/L) which exceed the quality standard of Indonesia's Ministry of Environment and Forestry Law No. 5 of 2014. Moving-bed biofilm sequencing batch reactor is an attached growth system which able to tolerate high concentrations of organic matters in wastewater. This experiment was performed in a lab-scale reactor by varying detention time 12, 18 and 24 h. The ratio of BOD₅/COD before and after the treatment was increased from 0.46-0.69. It happens presumably due to the hydrolysis process which convert the complex organic compound to simple organic compound. During the experiment, the optimum dissolved oxygen was 2.41-2.62 mg/L. The results showed the COD removal efficiency at 12, 18 and 24 h detention time, respectively are 84-89, 86-91 and 88-92%. The decreasing of organic loading rate will result in increased removal efficiency of COD. Therefore, the optimum organic loading rate to reach COD removal efficiency above 88% is in the range of 3.27-4.27 kg COD/m³ day. The highest removal efficiency reached was 92% in 24 h detention time with organic loading, dissolved oxygen and pH effluent, respectively at 3.27 kg COD/m³ day, 2.51 mg/L and 8.6. This study, showed that MBSBR system has an acceptable performance to treat wastewater with a high load of organic carbon at a certain detention time.