Abstract:
To study the effect of Hydraulic Retention Time (HRT) to COD removal and biogas production of anaerobic fluidized bed system by using rubber granule as a media for treating synthetic wastewater. The dimensions of reactor are 2.0 m. height, an internal diameter of 0.05 m. and a total volume of 3.5 liter. The experiments were operated with low 4 hydraulic retention time as 8, 5, 2 and 0.4 hrs, while 0.4 hrs was uncirculated wastewater condition in a reactor. Start-up process was performed by step up feeding of synthetic wastewater into the reactor with organic loading rate from 0.5 to 5.0 kg.COD/cb.m.-d. until the system reaches the steady state. Then proceed to the experimental treatment by adjusting the flow rate and COD value corresponding to various HRTs in order to control the organic loading rate constant at 8 kg.COD/cb.m./d. Based on the experimental results, anaerobic fluidized bed system using rubber granule as a media at hydraulic retention time of 8, 5, 2 and 0.4 hrs achieved the COD removal efficiency of 89.4, 82.3, 70.1 and 70.3% and the biogas production were 0.40, 0.38, 0.36 and 0.35 L./g.COD removed respectively. The result indicated that anaerobic fluidized bed still show effective in the treatment of COD, base on the advantages of this system which is able to maintain the high concentration of biomass and good water distribution around the tank. Moreover, it can be concluded that the crumb rubber was the appropriate media in anaerobic fluidized bed system. The crumb rubber could compatible with microorganisms in the system, making methanogen groups could created biofilm layer surrounding the rubber beads. In addition, crumb rubber material is low density and easy to create fluidized conditions with low energy to control and maintain this situation at all times.