Pilot plant studies for the removal of heavy metals from industrial wastewater using adsorbents

With the development of industrialization and human activities, discharge of waste water containing heavy metals in the environment is increasing day by day. It causes serious threats to the human civilization and the flora and fauna in this earth. Conducting polymers like polypyrrole and polyaniline can be used for treating wastewater due to their inherent ion absorption properties. This article has been focused on the development of polypyrrole coated bio-composites and their potential about the removal of heavy metals from industrial wastewater. Adsorption process can be successfully employed to remove heavy metals from the wastewater by the treatment of water with polypyrrole-coated composites. It was reported in literature that the polypyrrole and polyaniline-coated adsorbents had good adsorption capacities for Mg, Fe, Cu, Cd, Pb, Zn, and Ni. Polypyrrole-coated saw dust, rice husk, chitin, and cellulosic materials could be able to remove Cr, Fe, Cu, and Zn from wastewater. This method would be a replacement for costly conventional methods of removing heavy metal ions from wastewater. It is expected that this method would be an alternative for waste water treatment which will benefit the industries in future.

Download Full-text

Bioleaching of heavy metals from contaminated aquatic sediments using indigenous sulfur-oxidizing bacteria: a feasibility study

Water Science & Technology ◽

10.2166/wst.1998.0776 ◽

1998 ◽

Vol 37 (6-7) ◽

pp. 387-394 ◽

Cited By ~ 16

Author(s):

H. Seidel ◽

J. Ondruschka ◽

P. Morgenstern ◽

U. Stottmeister

Keyword(s):

Heavy Metals ◽

Pilot Plant ◽

River Sediments ◽

Chemical Properties ◽

Leaching Potential ◽

Removal Of Heavy Metals ◽

Sulfur Oxidizing ◽

Physical And Chemical ◽

Better Than ◽

Sulfur Oxidizing Bacteria

The removal of heavy metals from contaminated river sediments was studied using suspension leaching under laboratory conditions and percolation leaching in a pilot plant. The leaching potential of indigenous sulfur-oxidizing bacteria was compared with acid treatment. Bioleaching with elemental sulfur as substrate was found to be better than treatment with sulfuric acid for the solubilization of all metals tested. The physical and chemical properties of the sediments used in this study did not affect leaching capacity under optimum conditions in the laboratory. Under the practical conditions in the pilot plant, the redox state of sludge had a considerable influence on leaching efficiency. In a deposited oxic sediment with good permeability, about 62% of the metals tested were removed by percolation leaching after 120 days. Zn, Cd, Ni, Co and Mn were sufficiently leached to enable treated sediments to be reused as soil. In a freshly dredged anoxic sediment, only a total of 9 % of metals were removed. The results indicate that freshly dredged sediments need to undergo pretreatment before percolation leaching to improve mass transfer and to activate the leaching active bacteria.

Download Full-text