Pengaruh Hydraulic Retention Time (HRT) dan pH pada Proses Asidogenesis Limbah Cair Pabrik Kelapa Sawit (LCPKS) Menggunakan Temperatur Termofilik

Abstract

Acidogenesis is a complex process in which anaerobic microorganism collaboratively decompose organic compounds to volatile fatty acid. This research aimed to obtain the optimal Hydraulic Retention Time (HRT) in the acidogenesis process using Palm Oil Mill Effluent (POME) at thermophilic temperature. Initially, the suitable loading up was determined by varying the HRT 20, 15, 10 and 4 days in the continuous stirred tank reactor (CSTR) with mixing rate 200 rpm, pH 6,0 ± 0.2, and temperature 55 oC. Next, suitable pH was determined by varying the pH at 6,0; 5,5; 5,0 and 4,5. Analysis solids (TS, VS, TSS and VSS), COD and VFA conducted to assess changes in organic compounds degraded to VFA. Stable microbial growth characterized by an increased concentration of VSS obtained at HRT 4 with COD reduction amounted to 52,9%, while the highest production of total VFA and VFA/alkalinity ratio obtained at HRT 20 with respective values of 6.992,9 mg/L and 3,43. The optimal pH was achieved at pH 5 with the production of total VFA achieved was 9.723,9 mg/L and the concentration of acetic acid, propionic acid and butyric acid were 4.455,6; 1.544,5; and 3.723,8 mg/L, respectively. While COD degradation was 44% and VFA/alkalinity ratio was 12,6.