Darwin Gani

The purpose of this study was to investigate the potential of methane production from anaerobic co-digestion of coco husk with digested swine manure. The experiment was set up in the batch system. Inoculum utilized in this experiment was derived from semi-continuous reactor run at steady state condition, with 25 days of hydraulic retention time and mesophilic condition. The temperature applied in this experiment was maintained under mesophilic condition, which was 35 o C. The highest methane productivity generated from anaerobic co-digestion of cocoa husks with digested swine manure (CH) was 345.8 ± 7.82 mL/day, which was higher compared with the anaerobic digestion of digested swine manure alone (286.97 ± 16.8 mL/day). CH reactors had less methane yield (60.3 ± 1.6 mL CH4/g VS added) compared with control reactors (104.1 ± 4.4 mL CH4/g VS added). However, chemical oxygen demand (COD) removal and volatile solids (VS) reduction of CH reactors were 45.1 ± 4.3%, 19.9 ± 0.5%, respectively, which were higher compared with control reactors (20.3 ± 5.0%, 14.7 ± 1.0%, respectively). Based on the results, a lower biodegradation efficiency of anaerobic co-digestion of cocoa husks with digested swine manure was affected by the high cell wall content of cocoa husks that may hinder the anaerobic microbes to convert cocoa husk into methane.

This study aimed to investigate potential methane production through anaerobic co-digestion of cocoa husk and digested swine manure with different total solids concentration. The research was conducted in batch experiments. Anaerobic co-digestion processes were carried out at different level of solids concentration including 2%, 3%, and 4% total solids concentration. The anaerobic co-digestion process was run at 500 mL batch reactors under constant temperature (35ºC) and agitation (270 rpm). Based on the results, volatile solids reduction of control and cocoa husk co-digested with digested swine manure (CH) reactors were 22.69 ± 0.16% and 40.51 ± 0.69%, respectively. In terms of total solids reduction, control and CH reactors had 19 ± 0.34% and 22.7 ± 2.23%, respectively. This condition lead CH reactors run at 4% TS to produce more methane within 30 days of digestion, where in terms of total methane production they generated about 50.68% higher compared with that produced under 2% TS, and around 22.33% higher compared with that produced in 3% TS. In terms of methane yield, CH reactors achieved the highest methane yield at 2% TS which was 60.25 ± 1.60 mL CH 4 /g VS added, and the lowest methane yield was obtained at CH reactors operated in 4% TS which was around 38.99 ± 1.57 mL CH 4 /g VS added. Reference to this paper should be made as follows: Darwin, Cheng, J.J., Gontupil, J. and Liu, Z. (2016) 'Influence of total solid concentration for methane production of cocoa husk co-digested with digested swine manure', Int.

ABSTRAK Thermal pre-treatment diberikan pada limbah tanaman jagung dengan tujuan untuk memecahkan kandungan lignin yang terdapat pada limbah tanaman jagung sehingga memudahkan mikroorganisme anaerobik untuk mengkonversi polimer yang berupa selulosa dan hemiselulosa menjadi biogas. Tujuan dari penelitian ini adalah untuk melakukan kajian mengenai penerapan thermal pre-treatment pada limbah tanaman jagung terhadap proses anaerobik digesi yang meliputi efisiensi proses digesi dan produksi biogas yang dihasilkan. Penelitian ini dilakukan dengan menggunakan reaktor tipe batch yang suhunya dipertahankan pada kondisi mesophilic atau di atas rata-rata suhu kamar (33 ± 2 o C). Hasil penelitian diperoleh bahwa thermal pre-treatment yang diberikan pada limbah tanaman jagung mampu mempercepat proses produksi biogas pada 10 hari pertama sehingga dapat mengurangi lag-phase pada proses anaerobik digesi. Limbah tanaman jagung yang diberikan thermal pre-treatment mengalami perlambatan produksi biogas pada hari ke 26 dengan rata-rata total produksi 12.412,5 mL untuk limbah tanaman jagung yang diberikan thermal pre-treatment selama 15 menit, dan 12.310 mL untuk limbah tanaman jagung yang diberikan thermal pre-treatment selama 25 menit, sedangkan limbah tanaman jagung yang tidak diberikan pre-treatment menghasilkan produksi biogas sebesar 12.557 mL pada hari ke 26. Produksi biogas harian tertinggi terjadi pada substrat yang diberikan thermal pre-treatment 25 menit, dengan produksi biogas tertinggi pada hari ke 9 dengan rata-rata produksi sebesar 915 mL. Substrat yang diberikan thermal pre-treatment 15 menit juga memproduksi biogas jauh lebih tinggi (772,5 mL) pada hari ke 9 jika dibandingkan dengan substrat tanpa diberikan pre-treatment yang hanya memproduksi biogas sebesar 405 mL. Data hasil penelitian menunjukkan bahwa limbah tanaman jagung yang diberikan thermal pre-treatment memperoleh biogas yield lebih tinggi dari pada yang tidak diberikan pre-treatment dimana 670,39 mL/g volatile solids untuk thermal pre-treatment 15 menit, 690,65 mL/g volatile solids untuk thermal pre-treatment 25 menit dan 456,37 mL/g volatile solids untuk limbah tanaman jagung yang tidak diberikan pre-treatment. Kata kunci: Thermal pre-treatment, limbah tanaman jagung, anaerobik digesi, biogas ABSTRACT Thermal pre-treatment was given on corn stover in the purpose of breaking the lignin content; thus, it may help anaerobic microorganisms to convert polymer including cellulose and hemicelluloses into biogas. This study aimed to investigate the effects of thermal pre-treatment on corn stover in anaerobic digestion process related to the production of biogas as well as digestion process efficiency. This research was carried out by utilizing batch reactors where the temperature was maintained at mesophilic conditions above room temperature (33 ± 2 o C). Based on the result, it was known that thermal pre-treatment given on the corn stover may enhance anaerobic digestion process for biogas production at the first 10 days. This condition reduced the time of lag phase during anaerobic digestion. The biogas production of corn stover given thermal pre-treatment was slow at 26 days where their average total production were 12,412.5 mL,

Limbah tanaman jagung merupakan limbah biomassa lignoselulosa yang terdiri dari lignin,
selulosa dan hemiselosula. Hemiselulosa dan selulosa merupakan polimer yang dapat
dikonversikan menjadi biogas. Penelitian ini bertujuan untuk melihat potensi produksi biogas
melalui teknologi co-digesi limbah tanaman jagung yang memiliki kandungan karbon tinggi
dengan manure sapi yang memiliki kandungan karbon rendah dan tinggi kandungan nitrogen,
sehingga dapat meningkatkan effisiensi dan menyeimbangkan proses digesi untuk produksi
biogas dan digestate. Metode yang digunakan dalam penelitian antara lain: limbah tanaman
jagung yang sudah digiling ± 2 mm dicampurkan dengan manure sapi yang telah melalui
treatment anaerobik. Proses anaerobik yang dilakukan yaitu pada konsentrasi 3% total solids.
Reaktor yang sudah diisikan dengan substrat meliputi reaktor yang hanya berisi digested
manure sapi dan reaktor yang berisi digested manure sapi dan limbah jagung yang diletakkan
di dalam thermostatic waterbath yang suhunya dipertahankan pada kondisi mesophilic (30-32
oC). Pengukuran produksi biogas dilakukan setiap hari dengan mencatat peningkatan level
gas pada gas meter. Dari hasil penelitian diketahui bahwa anaerobik co-digesi limbah jagung
dan digested sapi manure menghasilkan biogas jauh lebih tinggi (15969.5 mL) bila
dibandingkan dengan produksi biogas dari manure sapi yang tanpa ditambahkan limbah
jagung (887.5 mL).

This study aimed to investigate potential methane production through anaerobic co-digestion of rice straw and digested swine manure with different total solids. The research was carried out in bench scale with utilizing batch system. To evaluate the stability of anaerobic co-digestion process, the experiment was run in triplicate. The anaerobic co-digestion process was operated in 500 mL batch digesters under constant agitation speed and temperature. The agitation speed was maintained at 270 r/min. Temperature of the batch system was set and maintained at 35oC. Digested swine manure utilized in this experiment was obtained from semi-continuous digesters run at steady state condition, with 25 days of hydraulic retention time under mesophilic condition. Rice straw (RS) generated the highest methane production at 3% total solids (TS) which was around (1814±47.43) mL, where in this concentration, it had C:N ratio at 10.6:1. Rice straw obtained the highest methane yield at 3% TS, which was around (141.4±3.70) mL CH4/g volatile solids (VS) added. Rice straw also had the highest chemical oxygen demand (COD) removal and VS reduction at 3% TS which were around (52.97%±1.46%) and (61.81%±1.04%), respectively.

Anaerobic co-digestion of swine manure and corn stover for biogas production has been
studied in two completely-mixed and semi-continuously fed reactors (Reactor 1 and Reactor 2). Each
reactor had a working volume of 14 liters and was operated at 35°C, a hydraulic retention time of 25
days, and an agitation speed of 120 rpm. Initially the reactors were operated as duplicates and each
was fed with 560 ml of swine wastewater per day. After a stable performance had been achieved in
both reactors with almost the same results, corn stover was added to Reactor 2 to get a Carbon to
Nitrogen ratio (C:N) of 10:1. Since then 560 ml of swine wastewater and 14 g of corn stover have
been added to Reactor 2 every day to keep the C:N ratio at 10:1. In the meantime Reactor 1 has
been fed the same as previously.
Removal of chemical oxygen demand (COD), total kjeldahl nitrogen (TKN), fixed suspended solids
(FSS), and volatile suspended solids (VSS) was 52%, 1%, 54%, and 55%, respectively in Reactor 1.
When corn stover was added to Reactor 2, removal of COD, TKN, FSS, and VSS was 53%, 11%,
58%, and 59%, respectively. There was also a reduction of NH4-N by 15% in Reactor 2, probably
because of the better balance of nutrients compared to Reactor 1, where an increase of ammonium
was detected.
Average gas production was 274 ml per day in Reactor 1 and 3,910 ml per day in Reactor 2. Gas
chromatography (GC) analyses have shown that methane content is 67.8% in Reactor 1 and 50.7%
in Reactor 2. Methane yield in Reactor 1 and Reactor 2 was 0.22 and 0.18 m3 of CH4 per kg of COD
removed, respectively. Preliminary results indicate that corn stover could be substantially degraded
to methane in an anaerobic co-digestion with swine manure.