Laboratory Research of Hydrolysis-Acidogenesis Process of Primary Sludge

Hydrolysis-acidogenesis of primary sludge is a suitable method to produce readily biodegradable organic matter. Sludge retention time (SRT) is a significant technological parameter: when it is too short, the sufficient amount of short chain volatile fatty acids (SCVFAs) will not be produced. When SRT is too long, part of the produced SCVFAs will be consumed by bacteria-producing methane. The objective of this research was to determine the optimal SRT of the hydrolysis-acidogenesis process for the highest production of organic carbon content. For research on the hydrolysis-acidogenesis process, two laboratory methods were applied, and primary sludge from two wastewater treatment plants (WWTPs) was investigated. The obtained results showed that the optimal SRT was six days under investigated conditions. The maximum SCVFAs production and biochemical oxygen demand (BOD7) formation were achieved with the destruction of volatile suspended solids (VSS) of 5%.