Pengaruh Penghentian Natrium Bikarbonat terhadap Unjuk Kerja Fermentor Dengan dan Tanpa Recycle pada Proses Fermentasi Limbah Cair Pabrik Kelapa Sawit

Abstract

Based on the preliminary research, it was found that recycle sludge system can increase the rate of COD decomposition and the value of Volatile Solid (VS) so that biogas production can be increased. It was also found that the use of NaHCO3, in the anaerobic process can influence fermentation process. The increase of NaHCO3 can also be needed to neutralize pH and increase alkalinity. The objective of the research was to find out the amount of influence if NaHCO3 was stopped on biogas production, pH, and alkalinity with or without recycle. The research was conducted by using two liters of Continuous Stirred Tank Reactor (CSTR). The material used as ferment feedback was liquid waste from PKS ADOLINA PTPN IV with supplements such as sodium bicarbonate (NaHCO3), trace metals FeCl2, NiCl.6H2O, and CoCl.6H2O. The observed variables were M-Alkalinity, Total Solid (TS), VS, and biogas production in Hydraulic Retention Time (HRT) in six days. The result of the research showed that biogas production of recycle system and the elimination of the average of 5,5-6,5 L/day of NaHCO3, using NaHCO3, 7-8,5 L/day, pH was stable, alkalinity was on the average of 1500 mg/L, decomposition rate of VS fermentation recycle which was produced if the additional NaHCO3 was stopped on the average of 60%, using 80% of NaHCO3 on the average of 5-6 L/day, using NaHCO3 6-8 L/day, ph was stable, decomposition rate of which was produced if the additional NaHCO3 was stopped on the average of 45%, using 55% of NaHCO3.

Berdasarkan penelitian-penelitian yang telah ada, diketahui dengan adanya sistem recycle sludge dapat meningkatkan laju dekomposisi COD, serta dapat meningkatkan nilai Volatil Solid (VS), sehingga meningkatkan produksi biogas. Diketahui bahwa penggunaan NaHCO3 dalam proses anaerobik dapat mempengaruhi proses fermentasi. Penambahan NaHCO3 juga sangat dibutuhkan sebagai penetral pH, dan meningkatkan alkalinitas. Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh jika dilakukan penghentian NaHCO3 terhadap produksi biogas, pH dan alkalinitas baik menggunakan sistem recycle maupun tanpa recycle. Penelitian dilakukan dengan menggunakan reaktor berpengaduk kontinu Continuous Stirred Tank Reactor (CSTR) bervolume 2 liter. Bahan yang digunakan sebagai umpan fermentor adalah limbah cair dari PKS ADOLINA PTPN IV, dengan bahan tambahan berupa natrium bikarbonat (NaHCO3), larutan logam (trace metals) FeCl2, NiCl.6H2O dan CoCl2.6H2O. Variabel-variabel yang diamati antara lain M-Alkalinitas, Total Solid (TS), VS, dan produksi biogas pada Hydraulic Retention Time (HRT) 6 hari. Dari hasil penelitian ini diperoleh produksi biogas sistem recycle dengan dihentikan penambahan NaHCO3 rata-rata 5,5-6,5 L/hari, menggunakan NaHCO3 7-8,5 L/hari, pH yang diperoleh stabil, alkalinitas yang dihasilkan rata-rata 1500 mg/L , laju dekomposisi VS fermentasi recycle dihentikan penambahan NaHCO3 rata-rata 60%, menggunakan NaHCO3 80%. Sedangkan untuk nonrecycle produksi biogas dihentikan penambahan NaHCO3 rata-rata 5-6 L/hari, menggunakan NaHCO3 6-8 L/hari, pH yang dihasilkan juga stabil, laju dekomposisi yang dihasilkan dihentikan penambahan NaHCO3 rata-rata 45%, menggunakan NaHCO3 55%.