Biogas production through Co-digestion of palm oil mill effluent with cow manure

Two-stage anaerobic fluidized bed is an innovation in anaerobic digestion technology intended to handle liquid waste with high organic loading and complex substrate. The process is based on separation between acidogenic/acetogenic and methanogenic processes. The first stage is anaerobic process to convert substrate (represented as soluble chemical oxygen demand/sCOD) into volatile fatty acids (VFA). The second stage is methanogenic process to convert VFA into biogas. This study aimed to separate acidogenic/acetogenic and methanogenic processes by means of limited injection of air (micro-aeration) and inoculum selection. Micro-aeration was introduced in acidogenic/acetogenic stage because the relevant microbes were facultative so that the obligate anaerobic methanogens will be suppressed. On the other hand, the methanogenic reactor was kept completely anaerobic to ensure methanogenic dominance over acidogenic/acetogenic ones. Two sources of inoculums were used in this study, i.e. anaerobically digested biodiesel waste and anaerobically digested cow manure. Both inoculums were taken from active biogas reactor treating biodiesel waste and cow manure, respectively. Experiments were run in batch reactors treating palm oil mill effluent (POME) as the substrate for the acidogenic/acetogenic reactor. After the reaction in the first stage reached the minimum substrate concentration, the content of the reactor was used as the substrate for the methanogenic reactor as the second stage. Routine measurements were taken for sCOD and VFA concentrations, biogas production, and methane concentration in the biogas. Results confirmed that micro-aeration maintained good performance of acidogenic/acetogenic process, which was indicated by peaks in VFA accumulation, while suppressing methanogenic activities as no methane produced in this stage. Digested biodiesel waste was superior inoculum to be compared to digested cow manure with respect to sCOD removal. In the methanogenic stage, digested biodiesel waste also performed better as inoculum as it led to higher VFA conversion, higher biogas production rate, and higher methane content in the biogas.

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PENAMBAHAN TANDAN KOSONG KELAPA SAWIT UNTUK MENINGATKAN PRODUKSI BIOGAS PADA PENGOLAHAN AIR LIMBAH SECARA ANAEROBIK

Jurnal Purifikasi ◽

10.12962/j25983806.v14.i1.5 ◽

2014 ◽

Vol 14 (1) ◽

pp. 11-20

Author(s):

Abdul Kahar ◽

Ira Aisya ◽

Waya Wulan Sari

Keyword(s):

Palm Oil ◽

Biogas Production ◽

Palm Oil Mill Effluent ◽

Cow Manure ◽

Anaerobic Reactor ◽

Empty Fruit Bunches ◽

Batch System ◽

Production Research ◽

Palm Oil Mill

Tujuan penelitian ini adalah mengetahui pengaruh penambahan tandan kosong kelapa sawit pada reaktor anaerobik terhadap produksi biogas limbah cair kelapa sawit. Bahan penelitian berupa limbah cair kelapa sawit, kotoran sapi dan variasi penambahan Tandan Kosong Kelapa Sawit (TKKS) 1%, 3% dan 5% dengan 2 kali ulangan dan waktu fermentasi selama 70 hari. Percobaan dilakukan dengan sistem batch dalam reaktor anaerobic, pada temperatur psychrophilic (27°C) dan temperatur. Mesophilic (37°C) dan kapasitas reaktor adalah 300 mL, dengan volume campuran sebanyak 210 mL yang berisi: a) LCKS, dan b) LCKS dengan tambahan kotoran sapi dengan rasio 1:2 (v/v). Reaktor anaerobik terhubung ke penampung untuk menghitung produksi biogas, yang diamati setiap hari selama 50 hari. Hasil penelitian menunjukkan bahwa produksi biogas tertinggi adalah pada limbah cair kelapa sawit, kotoran sapi, TKKS 5% sebesar 872,5 mL. Penambahan TKKS memberikan pengaruh terhadap produksi biogas limbah cair kelapa sawit pada hari ke 1-24. Penambahan TKKS yang optimal yaitu pada penambahan TKKS 5 %. Hasil penelitian menunjukkan produksi biogas pada temperatur mesophilic lebih besar daripada produksi biogas pada temperatur psychrophilic. The objective of research is to know the effect of empty fruit bunches in anaerobic reactor of palm oil mill effluent (POME) of biogas production. Research materials are this form of palm oil mill effluent, cows manure with a variation of Empty Fruit Bunches (EFB) addition of 1%, 3% and 5% with two replications and 70 days fermentation. The experiment was conducted in a batch system with the anaerobic reactor. It was conduct, at temperature psychrophilic (27°C) dan temperature mesophilic (37°C), with reactor capacity is 300 mL, and the volume of mixture is 210 mL which is contains: a) POME and b) POME with additional cow manure with the ratio of 1:2 (v/v). Anaerobic reactor was connected to the collector to calculate production of biogas. It was observed in every day during 50 days. The results showed that biogas production is highest in palm oil mill effluent, cow manure, EFB 5% is 872.5 mL. The addition of EFB give effect of palm oil mill effluent biobiogas production on days 1-24. The addition of empty fruit bunches which are optimal in the addition of 5 %. The results showed the biogas production at temperature mesophilic more hight than temperature psychrophilic.

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