Piyavadee Srivichai and Sakesun Thongtip

DOI: 10.14456/sjst-psu.2021.101

pp. 767 - 773

Abstract

The purpose of this research is to investigate the effects of mixing speed (MS) (5-175 rpm) and retention time (RT) (1-
35 days) on biogas production of starchy sediment (SS) that is substantial waste from the modified tapioca starch plants. The AD
was performed using biochemical methane potential (BMP) method. The two factor central composite design (CCD) has been
employed to design and response surface methodology (RSM) used to evaluate the digestion efficiency and performance. The
biogas yield (BY) can be as high as 403 ml/g TVS_added at an MS:RT ratio of 112:30, whereas the TVS removal measures equal to
65.07%. It indicated that the SS could be applied as the suitable substrate for AD by operating with this MS:RT ratio. However,
the signs of initial system instability were detected. It requires the further study about pH control by adding the chemical to
maintain the proper stability.