Effect of suspended solids removal methods on methane production from tapioca starch wastewater

This study aims to evaluate methods for removing suspended solids (SS) from tapioca starch wastewater to increase methane producing activity (MPA) and biochemical methane potential (BMP). Three methods for SS removal, filtration, centrifugation, and settling, were compared using raw wastewater that had a high SS concentration of over 3,000 mg/L. Filtration was found to be the best method and it increased the MPA by 44% while removing 100% of the SS. Centrifugation and gravity settling had substantial effects, increasing BMP by 7.7% and 6.1% and removing 98.4% and 15.5% of SS, respectively. While the SS concentration is the main factor for determining the success of an up-flow anaerobic sludge bed (UASB) system, this study showed that the carbohydrate to protein ratio signifies that the biochemical component of the wastewater is a key factor causing increases in MPA and BMP. The SS removal methods used in this study also led to higher carbohydrate/COD and protein/COD ratios, which can increase MPA and BMP values relative to conditions where SS removal is not performed.