Effect of Total Solid Content to Biogas Production Rate from Vinasse

Vinasse that has high COD and total solid content is bottom product of distillation from unit of bioethanol production. Vinasse treatment using anaerobic digestion produced biogas. The purpose of this research was investigation the effect of total solid content to biogas production rate from vinasse, pH profile and COD removal. This research used anaerobic digester-laboratory scale at room temperature and batch system. Initial pH for all media was adjusted at 7 with the aid of NaOH 10 N solution. The result showed that vinasse:water ratio of 1:3 (TS 7.015 +/- 0.007%) produced the most total biogas (37.409 mL/g COD) however vinasse:water ratio of 1:2 (TS 9.310 +/- 0.014%) had the biggest COD removal (23.580 +/- 0.532%) than others. Variables with TS more than 7.015 +/- 0.007% caused the overloading in the digester whereas below of that caused unstable in decomposition process. Total solid that was in high level indicated COD content of substrates in high level. The more of COD concentration of substrates in the digester caused the more of COD removal after fermentation process at anaerobic condition. Vinasse:water of 1:3 that was the best variable in this research had kinetic model of biogas production which was P = 37.485x exp[-exp[((6.665 x e/37.485)/37.485) x (0.959t)+1]]. Kinetic constants of A (biogas production potential), U (maximum biogas production rate), lambda (minimum time to produce biogas) were 37.485 mL/g COD, 6.665 mL/g COD. day, 0.959 days respectively