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PERSISTENCE OF PATHOGENS IN LAGOON-STORED SLUDGE
Citation:
Reimers, R., M. Little, T. Akers, W. Henriques, R. Badeaux, D. McDonnell, AND K. Mbela. PERSISTENCE OF PATHOGENS IN LAGOON-STORED SLUDGE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-89/015.
Description:
The project objective was to investigate pathogen inactivation in lagoon-stored municipal sludges. The in-field lagoons were located in Louisiana (New Orleans) and in Texas (Port Aransas), both semitropical areas of the United States. ach lagoon was filled with 7.56 m3 of anaerobically digested sludge to which a spike containing a mixture of salmonella livingstone, poliovirus Type 1, and eggs was added. The municipal sludge placed in each lagoon was from the respective local area. The field and laboratory data demonstrated that 15 mo of storage was required for pathogen inactivation to meet the U.S. Environmental Protection Agency's (EPA) Process to Further Reduce Pathogens (PFRP) criteria for lagoon-stored sludges in a semitropical climate. n this study, viable Ascaris eggs were inactlvated in 15 mo in the New Orleans lagoon where the temperature averaged about 25-C over a 5 mo period. lthough a similar temperature was observed for the Texas (Port Aransas) lagoon, all eggs were dead after 12 mo of storage, probably because of petroleum organics in the Texas sludge. Salmonella livingstone was inactivated in 4 to 6 mo in both lagoons at a log-reduction rate of 1.2 and 1.6 log Most Probable Number (NPN)/mo/1OO mL in New Orleans and Port Aransas sediments, respectively. otal coliforms and fecal coliforms declined 2 to 6 logs within 12 mo. ittle, if any, die-off of fecal streptococci, either on a volume or a gram dry weight basis, was noted in either lagoon. n increase of total coliforms was observed in both lagoons after 10 mo. oliovirus Type 1 was inactivated within 12 mo at rates ranging from 0.01 to 0.02 log PFU/mo/100 mL in the sediments of both lagoons.