Lead toxicity to the performance, viability, and community composition of activated sludge microorganisms

Li YUAN, Wei ZHI, Yangsheng LIU, Saikumar KARYALA, Peter J. VIKESLAND, Xi CHEN*, Husen ZHANG

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

88 Citations (Scopus)


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. (Graph Presented).

Original languageEnglish
Pages (from-to)824-830
Number of pages7
JournalEnvironmental Science and Technology
Issue number2
Early online date7 Jan 2015
Publication statusPublished - 20 Jan 2015
Externally publishedYes

Bibliographical note

We thank the anonymous reviewers for improving this manuscript. This work was supported by Husen Zhang’s startup funds provided by Virginia Tech College of Engineering. L.Y. acknowledges support from the China Scholarship Council (CSC) visiting scholarship. The work of X.C. was supported by National Natural Science Foundation of China (11172231 and 11372241), AFOSR (FA9550-12-1-0159), and ARPA-E (DE-AR0000396).


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