Ref ID : 1193
P.F. Strom, V.A. Matulewich, and M.S. Finstein; Concentrations of nitrifying bacteria in sewages, effluents, and a receiving stream and resistance of these organisms to chlorination. Appl.Environ.Microbiol. 31(5):731-737, 1976
Reprint
In File
Notes
Estimates of NH4+ and NO2- oxidizers in samples from four activated sludge plants treating mainly domestic sewage were obtained using a most-probable-number (MPN) technique. Ranges of concentrations per milliliter of each, respectively, were 1010 to 3880 and 79 to 145 in settled sewages, 32 to 7420 and 2 to 1010 in secondary effluents, and <0.1 to 622 and 0.1 to 70 in chlorinated secondary effluents. The results of this field study indicated that nitrifiers were more resistant to chlorination than fecal streptococci, which were also enumerated. In laboratory studies the survivals of these bacterial groups in secondary effluents were determined after exposure to chlorine residuals of up to 2 mg/liter streptococci, with NO2- oxidizers showing greater resistance than NH4+ oxidizers. Below the outfall of one of the plants that discharges heavily clorinated unnitrified effluent, NH4+ oxidizers amounted to approximately 200x10E5 per g of slime scraped from stream-bed rocks. Upstream of the outfall this was approximately 3x10E5 per g.