Anaerobically digested biosolids odor generation and pathogen indicator regrowth after dewatering

• Published in: Water research (Oxford) Vol. 45; no. 8; pp. 2616 - 2626
• Main Authors: Chen, Yen-Chih, Higgins, Matthew J., Beightol, Steven M., Murthy, Sudhir N., Toffey, William E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2011; Elsevier
• Subjects: Anaerobiosis; Applied sciences; Bacteria; Bacteria - growth & development; Biosolids; coliform bacteria; Colony Count, Microbial; Density; Desiccation; Dewatering; Exact sciences and technology; Fecal coliforms; Indicators; Methane - analysis; Microorganisms; Odor; odor compounds; Odorants - analysis; Odors; Other industrial wastes. Sewage sludge; oxygen; pathogens; Pollution; Regrowth; Shearing; Stabilization; Stimulation; sulfur; Volatile Organic Compounds - analysis; Volatile organic sulfur compounds; Waste Disposal, Fluid; Wastes; Water - chemistry; Fecal coliforms; Regrowth; Odor; Biosolids; Volatile organic sulfur compounds; Sulfur compounds; Microbiology; Stabilization; Waste treatment; Volatile organic compound; Coliforms; Dehydration; Sewage sludge; Anaerobic digestion; Indicator; Pathogenic; Bacteria; Air pollution; Biological treatment; Biological contamination; Organic compounds
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2011.02.014

The objective of this research was to investigate whether a preferential stimulation of microorganisms in anaerobically digested biosolids can occur after dewatering and if it can lead to pathogen indicator regrowth and odor generation upon storage. Laboratory incubation simulating biosolids storage indicates that both odorant generation, based on total volatile organic sulfur compound concentrations (TVOSCs) and pathogen indicator regrowth, based on fecal coliform densities follow similar formation and reduction patterns. The formation and reduction patterns of both odor compounds and fecal coliforms imply that groups of microorganism are induced if shearing disturbance is imposed during dewatering, but a secondary stabilization can be achieved soon after 1–2 weeks of storage. The occurrence of the induction is likely the microbial response to substrate release and environmental changes, such as oxygen, resulting from centrifuge shearing. The new conditions favor the growth of fecal coliforms and odor producing bacteria, and therefore, results in the observed fecal coliforms regrowth and odor accumulation during subsequent storage. However, when both substrate and oxygen deplete, a secondary stabilization can be achieved, and both odor and fecal coliforms density will drop. ► Preferential stimulation of microbes occurs by centrifuge dewatering of biosolids. ► Stimulation is likely by shearing release of substrates and introduction of oxygen. ► Stimulation results in fecal coliforms regrowth and organic sulfur odor production. ► A second stabilization can be achieved upon further storage of dewatered biosolids.