Treatment of palm oil mill effluent using modified rotating biological contactor with organic loading rate variations

Abstract

Indonesia is the world’s largest producer of palm oil or Crude Palm Oil (CPO). Palm oil production generates Palm Oil Mill Effluent (POME), which can harm the environment, if not properly treated. Untreated POME, with high Chemical Oxygen Demand (COD) levels, can lead to environmental degradations. Its high organic content and low acidity levels can also cause water pollution. This study modified the Rotating Biological Contactor (RBC) unit to treat POME, increasing the contact surface area between POME and microorganisms. It aimed to analyse the performance of the modified RBC unit, based on variations in organic loading rate (OLR). The study was conducted at a laboratory scale, with 2, 5, and 7 kgCOD/L/day organic loads. The results of this study revealed the highest percentage of removal obtained at an OLR variation of 7 kgCOD/L/day, with a removal rate of 70% for chemical oxygen demand (COD) concentration and 57% for ammonia concentration. Based on the research, the COD removal for organic loads of 7 kgCOD/L/day and 5 kgCOD/L/day decreased to 1900 mg/L and 2600 mg/L, respectively. Thus, the modified RBC unit would be more efficient with an organic load of 7 kgCOD/L/day. However, the COD concentration still did not comply with the water quality standards. Therefore, integrating the modified RBC unit with pre-treatment units, such as coagulation-flocculation, is necessary to achieve optimal effluent concentrations.