Lead Inhibition on Urea Hydrolyzing Microorganisms Under Batch Conditions

Kiliç, Ahmet; Koçyiğit, Hasan

doi:10.2478/v10133-010-0079-2

Cited by 1 publication

(2 citation statements)

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“…We observed a low 24-h Pb toxicity, which did not cause significant reduction in COD, NH 3 –N removal, and SOUR. This is inconsistent with previous reports on lack of inhibition of nitrification at Pb concentration as high as 40 mg L –1 and partial inhibition of glucose degradation by 64 mg L –1 Pb . However, when the exposure time was extended to 7 days, even 1 mg L –1 Pb was capable of significantly inhibiting NH 3 –N removal and SOUR.…”

Section: Discussioncontrasting

confidence: 99%

“…This is inconsistent with previous reports on lack of inhibition of nitrification at Pb concentration as high as 40 mg L −134 and partial inhibition of glucose degradation by 64 mg L −1 Pb. 35 However, when the exposure time was extended to 7 days, even 1 mg L −1 Pb was capable of significantly inhibiting NH 3 −N removal and SOUR. The toxic effect may be due to the cumulative Pb exposures, which were 7, 35, and 70 mg L −1 for the concentrations added.…”

Section: ■ Discussionmentioning

confidence: 99%

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Lead Toxicity to the Performance, Viability, And Community Composition of Activated Sludge Microorganisms

Zhi

Liu

et al. 2015

Environ. Sci. Technol.

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Lead (Pb) is a prominent toxic metal in natural and engineered systems. Current knowledge on Pb toxicity to the activated sludge has been limited to short-term (≤24 h) toxicity. The effect of extended Pb exposure on process performance, bacterial viability, and community compositions remains unknown. We quantified the 24-h and 7-day Pb toxicity to chemical oxygen demand (COD) and NH3–N removal, bacterial viability, and community compositions using lab-scale experiments. Our results showed that 7-day toxicity was significantly higher than the short-term 24-h toxicity. Ammonia-oxidizing bacteria were more susceptible than the heterotrophs to Pb toxicity. The specific oxygen uptake rate responded quickly to Pb addition and could serve as a rapid indicator for detecting Pb pollutions. Microbial viability decreased linearly with the amount of added Pb at extended exposure. The bacterial community diversity was markedly reduced with elevated Pb concentrations. Surface analysis suggested that the adsorbed form of Pb could have contributed to its toxicity along with the dissolved form. Our study provides for the first time a systematic investigation of the effect of extended exposure of Pb on the performance and microbiology of aerobic treatment processes, and it indicates that long-term Pb toxicity has been underappreciated by previous studies.

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Section: Discussioncontrasting

confidence: 99%

Section: ■ Discussionmentioning

confidence: 99%