GROWTH AND HEAVY-METAL REMOVAL BY KLEBSIELLA-AEROGENES AT DIFFERENT PH AND TEMPERATURE

A strain of K. aerogenes isolated from a wastewater treatment station was examined for its ability to grow in a media supplemented with maximum tolerance concentrations of Pb2+, Zn2+, Ni2+ and Cd2+, separately, at different temperatures and initial pH. At 28.degree. C and during the first 24 h, Pb2+ and Ni2+ had no effect on the growth of the bacteria; the presence of Zn2+ and Cd2+ decreased the cell count. Growth reached a maximum level after the 2nd day and started to decrease gradually. At 37.degree. C, the bacterial count was less than that at 28.degree. C in the presence of Pb2+ and Ni2+; the presence of Zn2+ and Cd2+ affected growth slightly. No bacterial multiplication occurred at 44.degree. C. There was little difference between heavy metal removal at 28.degree. and 37.degree. C. At 44.degree. C, no considerable removal took place. In general, a slightly acidic or neutral medium was better for growth and metal removal.