title: Kinetic responses of activated sludge microorganisms to individual and joint copper and zinc.
abstract: The individual and joint effects of copper and zinc on the growth kinetics of activated sludge microorganisms were studied in batch reactors fed with glucose as sole carbon source. The observed specific growth rate, substrate utilization rate and removal efficiency were determined at different concentrations of individual and joint Cu and Zn. Activated sludge microorganisms showed different kinetic responses to Cu and Zn, and the Haldane model seemed applicable for the inhibitory effect of Zn, while a first-order kinetics for Cu. Compared to Zn, Cu exhibited high toxicity to activated sludge microorganisms even at a very low concentration of 1.0 mg/dm3. However, Zn concentrations less than 40 mg/dm3 would stimulate the growth of activated sludge microorganism, and Zn acted as inhibitory chemical only at concentrations above this value. The combined effect of Cu and Zn could be regarded as neither synergistic nor antagonistic action.
authors.affiliation: Environmental Engineering Research Centre, School of Civil and Environmental Engineering, Nanyang Technological University, Singapore.
authors.forename: Yue-Mei
authors.initials: YM
authors.lastname: Lin
authors.forename: Xue-Fu
authors.initials: XF
authors.lastname: Yang
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001419:Bacteria; D003300:Copper / Q000009:adverse effects*; D007700:Kinetics; D008962:Models, Theoretical; D011157:Population Dynamics; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014865:Waste Disposal, Fluid; D015032:Zinc / Q000009:adverse effects*
chemical_list: D012722:Sewage; D003300:Copper; D015032:Zinc