Multistaged Anaerobic Sludge Digestion Processes

Abstract

Two multistaged anaerobic digestion systems, a four-stage thermophilic anaerobic digestion (4TAD), all at 55°C, and a four-stage anaerobic digestion with a tapered temperature configuration (4ADT) at 55, 49, 43, and 37°C, respectively, were studied to evaluate their solids, volatile organic sulfur compounds, and indicator organism (E. coli and fecal coliform) reduction potentials. The 4TAD system removed significantly more volatile solids from sludges than the 4ADT system (6%). However, the dewatered biosolids cakes from the 4ADT system generated fewer organic sulfur compounds than those from the 4TAD system. Both multistage systems showed better digestion efficiencies than single-stage mesophilic or single-stage thermophilic anaerobic digesters at the same overall retention time. However, the lowest organic sulfur compounds were observed from the single mesophilic system. Both multistage anaerobic digestion systems failed to dramatically remove DNA of the indicator organism, E. coli, quantified by real time polymerase chain reaction, even though the indicator organism densities measured by standard culturing methods satisfied EPA Class A biosolids requirements.

Employment of Organic Residues for Methane Production: The Use of Wastes of the Pulp and Paper Industry to Produce Biogas - A Case Study

“…Similarly, the experiments carried out by Kim, Novak, & Higgins (2011), affirm the effectiveness of the combination of three temperature phases. In their results, they obtained a VS reduction of about 57% [32].…”

“…The mesophilic from 1 to 3 days, the thermophilic from 5 to 15 days, and a mesophilic with a retention time from 5 to 15 days; The results of his research were 55% SV reductions, coliform and pathogen reduction, as well as a volumetric gas production of ~5.5 L CH4 (kgVS fed) −1 [31]. Similarly, the experiments carried out by Kim, Novak, & Higgins (2011), affirm the effectiveness of the combination of three temperature phases. In their results, they obtained a VS reduction of about 57% [32].…”

A critical review of biogas production and usage with legislations framework across the globe

“…Blonskaja et al (Blonskaja et al 2003 ) stated that by using a two-phase AD for distillery waste, a higher rate of methane would be produced. Kim et al (Kim et al 2011 ) implemented a four-phase scheme for activated slurry, which allowed extraordinary digestion productivity. The latest improvements in the utilization of molecular biology implements have developed the utility of included microorganisms and the knowledge of the AD practice.…”