Analysis of Retention Time on COD, pH, and Biogas Volume from Three Different Palm Oil Mills

Sri Wahyuna Saragih (Program Studi Teknologi Pengolahan Hasil Perkebunan, Institut Teknologi Sawit Indonesia, Medan, Indonesia)
Rizky Nadeak (Program Studi Teknologi Pengolahan Hasil Perkebunan, Institut Teknologi Sawit Indonesia, Medan, Indonesia)

RESWARA: Jurnal Riset Ilmu Teknik
Vol. 4 No. 4 (2026): RESWARA: Jurnal Riset Ilmu Teknik, October 2026

This study examines how retention time affects the effectiveness of anaerobic digestion in the treatment of Palm Oil Mill Effluent (POME). The study focuses on variations in Chemical Oxygen Demand (COD), pH levels, and biogas production using wastewater sourced from three palm oil processing facilities: Pagar Merbau POM, Adolina POM, and Cinta Raja POM retention Time. Anaerobic digestion was conducted for various retention periods of 0, 15, 30, 45, and 60 days. Evaluations were conducted to assess the reduction of organic contaminants, stabilization of pH levels, and the amount of biogas produced during the fermentation phase. The results showed that COD generally decreased with increasing retention time, although temporary increases were observed at days 30 and 60, while pH levels gradually moved towards a more stable state. Biogas production increased and peaked at 45 days, but no biogas production was observed at 60 days. These results indicate that retention time is crucial in influencing the effectiveness of anaerobic treatment methods. A retention period of 45 days offers the best conditions for the reduction of organic pollutants and for optimizing biogas production from POME.