Microbial aerosols from food-processing waste spray fields

Abstract

Federal legislation restricts the discharge of\nwaste from various industrial processes into\nrivers, lakes, or other waters. For this reason\ndisposal of wastewater by spraying onto cultivated,\ngrassed, or forested lands has come into\nuse. These waste disposal spray systems produce\ndroplets of water containing suspended\nmaterial that may become aerosolized as particles\nless than about 20 µ in diameter. Particles\nof this size will remain suspended in the\natmosphere and will travel long distances\ndownwind. The generation of such particles\nby commercial spray or sprinkler equipment\nmay be presumed because regardless of the\nsize distribution for water droplets leaving the\nsprinkler nozzle a number of particles of aerosol\nsize will develop through rapid evaporation.\nSolid materials, including microorganisms, suspended\nin the water become the nuclei of the\naerosol particles. Recent reviews have been\npublished regarding the aerosolization of microorganisms\nin sprays resulting from the treatment\nand disposal of wastewater from domestic\nwaste. Microbial aerosol particles were\nsampled up to 1.2 km downwind of the spray\nsource. Katzenelson and Teltch reported\naerosolized coliforms short distances downwind\nof spray fields for disposal of wastewater\ncontaining raw domestic waste and for disposal\nof effluent from a wastewater settling\npond.\nIn this report, studies were made of microbial\naerosols downwind from spray fields\nfor the disposal of potato processing wastewater.