Treatment of beet sugar wastewater by UAFB bioprocess.

The aim of this work was to study the treatment of strong beet sugar wastewater by an upflow anaerobic fixed bed (UAFB) at pilot plant scale. Three fixed bed bioreactors (each 60 L) were filled with standard industrial packing, inoculated with anaerobic culture (chicken manure, cow manure, anaerobic sludge digested from domestic wastewater) and operated at 32-34 degrees C with 20 h hydraulic retention time (HRT) and influent COD ranging between 2000-8000 mg/L. Under these conditions the maximum efficiency of organic content reduction in the reactor ranged from 75% to 93%.

Bioremediation of toxic heavy metals using acidothermophilic autotrophes.

Investigations were carried out to isolate microbial strains from soil, mud and water samples from metallurgically polluted environment for bioremediation of toxic heavy metals. As a result of primary and secondary screening various 72 acidothermophilic autotrophic microbes were isolated and adapted for metal tolerance and biosorption potentiality. The multi-metal tolerance was developed with higher gradient of concentrations of Ag, As, Bi, Cd, Cr, Co, Cu, Hg, Li, Mo, Pb, Sn and Zn.

Screening of thermoacidophilic autotrophic bacteria for covellite solubilization.

In an attempt to obtain suitable bacterial isolates for bioleaching of copper from chalcopyrite and covellite, soil samples taken from areas of the metal industry were screened using an enrichment procedure specially run at acidic pH and thermophilic temperature range, to overcome the limitations of mesophiles employed for the purpose besides having economic and environmental advantages. Of a total of 47 isolates, the most promising 3 having resistance to copper toxicity were evolved by subjecting them to gradually increasing concentrations of CuSO4 by acclimatization runs conducted on an environmental shaker for 125 d at 65 degrees C. The isolates, JVCu-8, JVCu-10, and JVCu-12, exhibited significantly enhanced bioleaching and copper tolerance ability at pH 3.