ABSTRACT
Tanneries are one of the water intensive industries that responsible for the generation of large quantity of wastewater. They include the tanning process of skins and hides of the animals, which requires a major portion of the fresh water. Currently the chrome tanning process is followed in tanneries, which involves huge amounts of chromium metal. The presence of chromium metal in tannery wastewater makes them very toxic in nature, leads to the contamination of soil and aquatic ecosystems; resulting in the loss of aquatic life forms. In conventional treatment, most of the inorganic ions including heavy metals are still present in treated wastewater and also in the sludge produced during the treatment. Although many advanced processes like reverse osmosis and membrane filtration proved to very successful in the chromium removal, but they have high building and operating cost.
Microalgae have been found to be very efficient in chromium metal removal from tannery wastewater. They use various mechanisms in order to sequestrate the chromium metal from wastewater, most of the chromium adsorbed is on the cell surface; while some portion undergoes bioabsorption. Further bioabsorbed chromium either extrudes extracellularly in a less toxic form or is incorporated in to cellular metabolic needs. Thus microalgae mediated remediation could provide a sustainable, cost effective and efficient approach to metal removal from the tannery wastewater.
