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Based on environmental and energetic analysis, a novel combined approach using bioelectrochemical systems (BES) followed by electrolysis reactors (ER) was tested for heavy metals removal from fly ash leachate, which contained high detectable levels of Zn, Pb and Cu according to X-ray diffraction analysis. Acetic acid was used as the fly ash leaching agent and tested under various leaching conditions. A favorable condition for the leaching process was identified to be liquid/solid ratio of 14:1 (w/w) and leaching duration 10h at initial pH 1.0. It was confirmed that the removal of heavy metals from fly ash leachate with the combination of BESs and ER is feasible. The metal removal efficiency was achieved at 98.5%, 95.4% and 98.1% for Cu(II), Zn(II), and Pb(II), respectively. Results of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) indicated that Cu(II) was reduced and recovered mainly as metal Cu on cathodes related to power production, while Zn(II) and Pb(II) were not spontaneously reduced in BESs without applied voltage and basically electrolyzed in the electrolysis reactors., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Great efforts have been made in China to retrofit and upgrade the existing municipal wastewater treatment plants (WWTPs) for enhanced removal of organic substrates and in particular nutrients. However, the removal of trace recalcitrant or hazardous organic chemicals, e.g. steroid estrogens, one group of typical endocrine disrupting chemicals, has long been overlooked. The extensive investigations on estrogen removal rates in global and Chinese WWTPs and the estrogen biodegradation kinetics results in batch laboratory experiments are reviewed in this study. The effects of estrogen initial concentration and nitrifying activated sludge are highlighted. Challenges existing in current estrogen studies are pointed out, which are relevant for researches on fate and behavior of similar down-the-drain chemicals in both Chinese and global WWTPs., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

A membrane-free baffled microbial fuel cell (MFC) was developed to treat synthetic Cu(II) sulfate containing wastewater in cathode chamber and synthetic glucose-containing wastewater fed to anode chamber. Maximum power density of 314 mW/m(3) with columbic efficiency of 5.3% was obtained using initial Cu(2+) concentration of 6400 mg/L. Higher current density favored the cathodic reduction of Cu(2+), and removal of Cu(2+) by 70% was observed within 144 h using initial concentration of 500 mg/L. Powder X-ray diffraction (XRD) analysis indicated that the Cu(2+) was reduced to Cu(2)O or Cu(2)O plus Cu which deposited on the cathode, and the deficient cathodic reducibility resulted in the formation of Cu(4)(OH)(6)SO(4) at high initial Cu(2+) concentration (500-6400 mg/L). This study suggested a novel low-cost approach to remove and recover Cu(II) from Cu(2+)-containing wastewater using MFC-type reactor., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The two-chamber microbial fuel cells (MFCs) were constructed with excess sludge as the anodic substrate and CuSO4 solution as the catholyte. The start up method, degradation of the anodic sludge, removal of the Cu2+ and products on cathode were investigated in the study. The results of batch experiments showed that Cu2+ can be used as cathodic electron acceptors, e. g. a stable voltage output of 0.478 V and a maximum power density of 536 mW/m3 were obtained at external resistance of 1 000 omega and Cu2+ concentration of 6 400 mg/L. The Cu2+ contained in wastewater could be removed effectively by the MFC process, e. g. 97.8% of Cu2+ was removed in a MFC reactor at the end of 288 h with initial Cu2+ concentration of 1 000 mg/L and external resistance of 0 omega. The cathodic products depended on cathodic reducibility, most of Cu2+ was deposited as Cu2O and a small part as Cu4 (OH), 6SO4 with lower cathodic reducibility, metal copper deposited on the cathode with higher cathodic reducibility. Using excess sludge as anodic substrate could support the MFCs for long-term operation. The acclimation stage of the exoelectrogenic bacteria on the anode had an impact on MFC performance and cathodic reduction of Cu2+, and the stability of exoelectrogenic biofilm on anode could be determined by monitoring the anode potential. The MFC with excess sludge as anodic substrate can degrade organic matter in sludge and accomplish Cu(2+) -containing wastewater treatment and copper recovery simultaneously.