Application of the conventional bioreactors based on biosorption for removal of heavy metals is limited because they can be broken through by heavy metals. The novel calcifying cyanobacteria reactors based co-precipitation of heavy metals with carbonate minerals induced by cyanobacteria may be a promising alternative technology to overcome the shortcomings of biosorption. In this study, removal of cadmium (Cd) from wastewater using three calcifying bacterium Nostoc calcicola reactors was investigated. N. calcicola can significantly increase aquatic phase pH in the reactor, associated with a decrease of dissolved inorganic carbon (DIC) content in the effluent. During the two-month operation of the bioreactors, over 98% of Cd removal was obtained with an initial Cd2+ concentration of 2.5 mu M. Cd2+ was mainly sequestrated in organic-bound fraction, followed by a small amount of carbonate and exchangeable fractions in the N. calcicola cell. A crystalline compound of Ca, C, and O, as well as a small amount of Cd on the surface of N. calcicola cell, was observed. The two-month high Cd removal efficiency of the N. calcicola reactors shows the calcifying cyanobacteria reactors have advantages over the conventional biosorption system, which can be shortly broken through for removal of heavy metals. Although the results revealed that calcifying cyanobacterium reactor is a promising way to remove Cd from water, assessment of its longer-term performance of heavy metal removal is needed. (C) 2015 Elsevier B.V. All rights reserved. Publication name | ECOLOGICAL ENGINEERING, 81 107-114; 10.1016/j.ecoleng.2015.04.012 AUG 2015 | Author(s) | Zhao, Chenxi; Fu, Qinglong; Song, Wenjuan; Zhang, Daoyong; Ahati, Jiaerheng; Pan, Xiangliang; Al-Misned, Fahad A.; Mortuza, M. Golam | Corresponding author | ZHANG Daoyong zhang-daoyong@163.com 1. Chinese Acad Sci, Xinjiang Inst Ecol & Geog, Xinjiang Key Lab Environm Pollut & Bioremediat, Urumqi 830011, Xinjiang, Peoples R China 2. Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550002, Guizhou, Peoples R China | View here for the details
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