Regrowth of fecal coliforms in class A biosolids.
Eight types of Class A biosolids were tested for fecal coliform (FC) reactivation and/or regrowth at 20, 35, and 50 degrees C for 21 days. Growth of FC did not occur at 20 or 50 degrees C, but it was observed in two samples incubated at 35 degrees C after a lag period of 48 hours. In undigested biosolids, final FC concentration exceeded 10(4) MPN/g, whereas in thermophilically digested biosolids, the final FC concentration remained below 10(3) MPN/g, as FC regrowth may have been affected by the presence of the anaerobic bacterial consortium responsible for the digestion process. Fecal-coliform reactivation and regrowth within treatment plant operations seem unlikely but can occur in land application of biosolids.
Jolis
Domènec
D
Clean Water Enterprise, Public Utilities Commission, San Francisco, CA 94124, USA. djolis@sfwater.org
D000693:Anaerobiosis / Q000502:physiology; D004755:Enterobacteriaceae / Q000254:growth & development*; D005243:Feces / Q000382:microbiology; D012037:Refuse Disposal / Q000379:methods* / Q000592:standards; D012722:Sewage / Q000382:microbiology*; D013696:Temperature; D013997:Time Factors; D018508:Water Purification / Q000379:methods
D012722:Sewage