Characterization of Hydrolysis Kinetics in Staged Anaerobic Digestion of Wastewater Treatment Sludge Publisher Pubmed



Zamanzadeh M^{1, 2} ; Parker WJ¹ Show Affiliations
Source: Water Environment Research Published:2018

Abstract

The hydrolysis of mixed primary and secondary sludges in two-stage anaerobic digestion was evaluated and compared with conventional single-stage digestion, using various temperature-phased configurations of M1-M2, M1-T3, T1-T2, and T1-M3. A dual hydrolysis model best described the hydrolysis in all tests. This model was also able to consistently estimate the readily and slowly fractions of particulate chemical oxygen demand (COD) of raw sludge used in the tests. The hydrolysis kinetic coefficients (Khyd-s and Khyd-r) estimated for the mesophilic digesters were significantly greater in the short hydraulic retention time (HRT) M1 digester than those of the extended HRT digesters. Conversely, at thermophilic temperatures only Khyd-r was greater in short HRT T1 digester when compared to the extended HRT digesters. The increased Khyd-r and reduced Khyd-s values due to staging effect were explained with surface reaction models and endogenous decay. The temperature dependency of Khyd-s and Khyd-r was also explored in the staged digesters.