Strategi Start-Up Produksi Biogas Dari Vinasse: Transisi Operasi dari Kotoran Sapi ke Vinasse

Abstract

Vinasse utilization as biogas forming substrate requires special handling because of it’s acidic state which is inhibitor to methanogens. At start-up, the performance of microbial group should be in state of equilibrium between methanogens and non-methanogens. This is attempted by adding inhibitor substrates incrementally. Start-up conduct in semi continue process with vinasse dry base composition 0% (S0), 50% (S1), 75% (S2), 90% (S3) up to 100% (S4). Biodigester loading rate is 40 kg/(m3/hari) with 8 litre effective slurry volume. Substrat is fed at 6,5% TS. The best pH stability obtained on S2 feed composition which is 6.3 for eleven consecutive days.This reflects the balance of methanogen and non-methanogenic microbes performance. The highest average daily biogas production was achieved at feed composition S3 of 3780mL even though the average pH tended to decrease to 6.18. At S4, pH and average biogas volume is decreased significanly to 5.9 and 1932mL.Pemanfaatan vinasse sebagai substrat penghasil biogas memerlukan penanganan khusus karena keasamannya bersifat inhibitor terhadap metanogen. Pada start-up biodigester diupayakan adanya keseimbangan mikrobia metanogen dan non metanogen dengan pemberian penambahan komposisi substrat yang mengandung inhibitor secara bertahap. Start-up dilakukan dengan proses semi kontinyu mengunakan campuran komposisi basis berat kering vinasse 0% (S0), 50% (S1), 75% (S2), 90% (S3) hingga 100% (S4). Loading rate biodigester 40 kg/(m3/hari) dengan volume efektif slurry 8 liter. Umpan diberikan pada 6,5% TS. Pada komposisi umpan S2 didapatkan kestabilan pH terbaik selama 11 hari sebesar 6,3 yang mencerminkan keseimbangan mikrobia metanogen dan non metanogen. Produksi rerata harian biogas tertinggi tercapai pada komposisi umpan S3 sebesar 3780mL meskipun rerata pH cenderung turun menjadi 6,18. Pada komposisi umpan S4, rerata pH turun lebih jauh lagi menjadi 5,9 dan produksi rerata harian biogas menurun hingga 1932m