American Society of Civil Engineers


Removal of Heavy Metals and COD by SRB in UAFF Reactor


by Mahmoud El Bayoumy, (Asst. Lect., Prof. of Sanitary Engrg., Fac. of Engrg., Ain Shams Univ., Abassia, Cairo, Egypt), J. K. Bewtra, (Prof. of Envir. Engrg., Dept. of Civ. and Envir. Engrg., Univ. of Windsor, Windsor, ON, Canada N9B 3P4), Hamdy I. Ali, (Asst. Lect., Prof. of Sanitary Engrg., Fac. of Engrg., Ain Shams Univ., Abassia, Cairo, Egypt), and N. Biswas, (Prof. of Envir. Engrg., Dept. of Civ. and Envir. Engrg., Univ. of Windsor, Windsor, ON, Canada N9B 3P4)

Journal of Environmental Engineering, Vol. 125, No. 6, June 1999, pp. 532-539, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9372(1999)125:6(532))

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Document type: Journal Paper
Abstract: Sulfate-reducing bacteria under anaerobic conditions reduce sulfate, SO4–², to sulfide, S–², which in turn can effectively precipitate heavy metals. In this research project, sulfate-reducing bacteria were grown in an upflow anaerobic fixed-film (UAFF) reactor using optimum growth conditions obtained in previous studies. These reactors were then fed with different heavy metals at increasing loading rates until complete failure occurred as metal removal reached zero and residual sulfide dropped to zero. The metal concentrations were measured as total, dissolved, and free ions both in the influent and in the effluent streams. The results of this research showed that 100% removal efficiencies could be obtained with individual concentrations up to 200 mg/L for Cu, 150 mg/L for Ni and Zn, 75 mg/L for Cr, 50 mg/L for Cd, and 40 mg/L for Pb. Also, the corresponding organic matter removal as total organic carbon was found to be about 50% of the influent total organic carbon. A set of mathematical equations were derived to express the mass balance inside the UAFF reactor, with respect to metal influent concentrations and sulfide production. These equations were corrected by incorporating a correction product, α.β, to represent the toxicity effect of the increasing metal concentrations.


ASCE Subject Headings:
Anaerobic treatment
Bacteria
Heavy metals
Organic carbon
Abatement and removal
Sulfates