American Society of Civil Engineers


Multistaged Anaerobic Sludge Digestion Processes


by Jongmin Kim, (corresponding author), (Infilco Degremont, Inc., Richmond, VA 23229; formerly, Research Assistant, Dept. of Civil and Environmental Engineering, Virginia Tech E-mail: Jongmin.Kim@infilcodegremont.com), John T. Novak, M.ASCE, (Dept. of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061.), and Matthew J. Higgins, A.M.ASCE, (Dept. of Civil and Environmental Engineering, Bucknell Univ., Lewisburg, PA 17837.)

Journal of Environmental Engineering, Vol. 137, No. 8, August 2011, pp. 746-753, (doi:  http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0000372)

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Document type: Journal Paper
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.


ASCE Subject Headings:
Anaerobic treatment
Wastewater management
Heat treatment
Remediation
Odors
Pathogens
Sludge

Author Keywords:
Anaerobic treatment
Wastewater management
Heat treatment
Remediation
Odors
Pathogens