Infectious Disease Hazards of Landspreading Sewage Wastes
1978
Burge, Wylie D. | Marsh, Paul B.
Major increases are currently taking place in the United States in the application of sewage wastes to agricultural land. This paper reviews literature relating to the question of whether such applications involve hazard from human disease organisms. Evidence on the matter is still inadequate. Processed sewage wastes often contain residual pathogenic viruses, bacteria, cysts of protozoa, and ova of helminths, but most sewage-related disease outbreaks have been attributed to use of raw sewage waste water, raw sludges, or night soils on food crops consumed raw, to contamination of drinking water from septic tanks, or to consumption of raw shellfish from sewage-polluted waters. Although subject to relatively high levels of exposure to pathogens in aerosols, waste water treatment plant workers appear to be unaffected, but data on this are limited. Percolation of waste water at a moderate rate through soils of medium to fine texture removes most bacteria and viruses; pathogen movement in surface runoff water may present a greater hazard for spreading disease. Techniques that completely disinfect sludges may fail to stabilize them so that putrefaction is a problem. Properly conducted composting stabilizes raw sludge and destroys most pathogens. Certain fungi and actinomycetes generated during composting may have allergenic potentialities of import for workers at sludge composting sites.
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