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Low‐Temperature Inactivation of Fecal Coliforms in Sludge Digestion
Author(s) -
Puchajda Bartek,
Oleszkiewicz Jan,
Sparling Richard,
Reimers Robert
Publication year - 2006
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143006x101638
Subject(s) - mesophile , propionate , chemistry , anaerobic digestion , butyrate , food science , fecal coliform , digestion (alchemy) , valerate , microbiology and biotechnology , bacteria , chromatography , biochemistry , biology , fermentation , organic chemistry , methane , ecology , genetics , water quality
The goal of this research was to demonstrate the ability to achieve Class A pathogen standards in nonthermophilic acid digesters. It was proposed that the key mechanism responsible for fecal coliform inactivation was the presence of un‐ionized volatile fatty acids. Lab‐scale acid digesters were assembled and operated in a batch mode for 5 days at mesophilic (38°C) and low‐mesophilic (21°C) temperatures and at different solids concentrations. The key factor recognized for successful pathogen inactivation was pH, which is also the main factor driving the shift in organic acids toward the un‐ionized form. Compared to conventional mesophilic acid digestion, low‐mesophilic acid digestion was effective in fecal coliform inactivation because the process maintained lower pH throughout the duration of the experiment, offered continuous release of organic acids, and showed higher concentrations of organic acids in un‐ionized form, including acetate, propionate, butyrate, and valerate.