Class B alkaline stabilization to achieve pathogen inactivation.
Liming is a cost-effective treatment currently employed in many Class B biosolids production plants in the United States. A bench scale model of lime stabilization was designed to evaluate the persistence of viral, bacterial and parasitic pathogens. The survival of fecal coliforms, Salmonella, adenovirus type 5, rotavirus Wa, bacteriophage MS-2, Cryptosporidium parvum oocysts, Giardia lamblia cysts, and Ascaris lumbricoides ova was evaluated under lime stabilization conditions in a water matrix. Fecal coliforms and Salmonella were undetectable following 2 hours of lime stabilization, demonstrating a 7-log reduction. Adenovirus, MS-2 and rotavirus were below detectable levels following 2 h of liming, demonstrating a 4-log reduction. G. lamblia cysts were also inactivated. A. lumbricoides ova remained viable following 72 hours of liming as did C. parvum oocysts. While this study confirmed that Ascaris ova are resistant to liming, their scarcity in sludge and low recovery efficiencies limit their use as indicator. The persistence of C. parvum oocysts after exposure to lime, suggests that this parasite would be a better choice as indicator for evaluating biosolids intended for land application. The studies done with adenovirus Type 5, rotavirus Wa and male specific bacteriophage provided preliminary data demonstrating similar inactivation rates. Monitoring anthropogenic viruses is a time consuming, labor intensive and expensive process. If further studies could demonstrate that phage could be used as an indicator of other enteric viruses, enhanced monitoring could result in greater acceptance of land application of biosolids while demonstrating no increased public health threat.
Bean
Christine L
CL
Department of Microbiology, University of New Hampshire, 35 Colovos Rd, ETB Hall Rm. 230, Durham, NH 03824, USA.
Hansen
Jacqueline J
JJ
Margolin
Aaron B
AB
Balkin
Helene
H
Batzer
Glenda
G
Widmer
Giovanni
G
D000818:Animals; D017164:Ascaris lumbricoides / Q000187:drug effects / Q000502:physiology; D001419:Bacteria / Q000187:drug effects; D017610:Calcium Compounds / Q000494:pharmacology*; D016785:Cryptosporidium parvum / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D016829:Giardia lamblia / Q000187:drug effects / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D020128:Inhibitory Concentration 50; D050296:Microbial Viability / Q000187:drug effects; D033661:Oocysts / Q000187:drug effects; D010087:Oxides / Q000494:pharmacology*; D014780:Viruses / Q000187:drug effects; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000469:parasitology; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods*
D017610:Calcium Compounds; D010087:Oxides; D014867:Water; C016538:lime