The Start-up of Hybrid, Anaerobic up-flow Sludge Blanket (HUASB) under a Range of Mesophiclic and Thermophilic Temperatures

We have examined the effect of gradual increase of the temperature on the performance of anaerobic process of palm oil mill effluent (POME), and sludge granules development. Two hybrid up-flow anaerobic sludge blanket (HUASB) reactors R1 and R2 were employed to be run at 27±2 and 37±1°C, respectively. R1 was kept at room temperature for the whole experiment, where the temperature of R2 was increased up to 49oC (3oC after every steady-state occurrence). Maximum COD removal of 91% was obtained in R2 at optimum temperature of 46°C, while 84% was recorded in R1. Additional parameters were applied to evaluate the performance of the process, i.e. total suspended solids (TSS), Turbidity, and Color. The imaging of sludge aggregate has revealed the effect of temperature on granulation development during the experiment. Throughout the operation period, it can be seen that the microbial growth rate was significantly affected by temperature. Hence, the use of HUASB reactor could be productively implemented for POME treatment as an efficient system under the mesophilic and thermophilic temperatures.