THE EFFICACY OF EMPLOYING BACILLUS GLOBIGII AS A PARTICULATE TRACER IN AQUATIC SYSTEMS.

The use of BACILLUS GLOBIGII spores as a particulate tracer for surface and subsurface systems was investigated. Thermal pretreatment allowed the tracer to be used in situations where large bacterial concentrations were present. The resulting large red-orange colonies on manitol plates were easily quantified. In suspended growth reactor systems, the residence times obtained using B. globigii spores were statistically different from those obtained using a miscible tracer. However, the residence times obtained for B. globigii and the common environmental bacteria E. coli were statistically indistinguishable. In porous media, B. globigii and E. coli yielded statistically similar tracer curves that were different from those obtained using the miscible fluorescein tracer. Based on these results, it was concluded that B. globigii has excellent potential as an environmental particle tracer. Field tests, conducted in aerobic and anaerobic digesters, confirmed the utility as a particulate tracer.