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ENVIRONMENTAL MONITORING OF A WASTEWATER TREATMENT PLANT
Citation:
Johnson, D., D. Camann, H. Harding, AND C. Sorber. ENVIRONMENTAL MONITORING OF A WASTEWATER TREATMENT PLANT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/1-79/027 (NTIS PB80103211), 1979.
Description:
A wastewater aerosol monitoring program was conducted at an advanced wastewater treatment facility using the activated sludge process. This plant was recently constructed next to an elementary school in Tigard, Oregon. Wastewater aerosols containing pathogenic organisms are generated by the aeration basin (within 400 meters of the classroom area) and by an aerated surge basin (within 50 meters of the school playground). From a preliminary microbial screen of the wastewater, predominant indicator and pathogenic microorganisms were selected for routine wastewater and aerosol monitoring. The geometric mean aerosol concentrations at 30 to 50 meters downwind of the aeration basin were 5.8 cfu/cu.m. of total coliforms, 2.0 cfu/cu.m. of fecal streptococci, 9.1 cfu/cu.m. of mycobacteria, 7 cfu/cu.m. of Pseudomonas, 0.7 pfu/cu.m. of coliphage, and <0.0009 pfu/cu.m. of enteroviruses. The inability to detect enteroviruses in air resulted from their low concentration (relative to other test organisms) in the wastewater and from their adsorption onto and incorporation into the mixed liquor suspended solids which are not easily aerosolized. While it is a relatively insensitive measure, attendance at the nearby school and eight control schools provided no evidence of adverse effects from wastewater treatment plant operation. If any adverse effects had occurred, it was slight enough to be completely obscured by the usual school absenteeism factors.