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Bioremediation of Tannery Effluents Using a Consortium of Blue–Green Algal Species
Author(s) -
Shashirekha Viswanaathan,
Sridharan Melatheru Ramanujam,
Swamy Mahadeswara
Publication year - 2011
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201000548
Subject(s) - chemical oxygen demand , biosorption , biochemical oxygen demand , effluent , oscillatoria , freundlich equation , bioremediation , pulp and paper industry , environmental chemistry , sorption , chemistry , chromium , langmuir , sulfate , sorbent , environmental science , environmental engineering , adsorption , sewage treatment , cyanobacteria , contamination , ecology , geology , biology , organic chemistry , paleontology , bacteria , engineering
Trivalent chromium in the form of basic chromium sulfate (BCS) is used for tanning hides/skins and is a strong pollutant of the soil and water bodies. Significant quantities of unutilized chemicals, such as sulfates, chlorides, are also discharged, contributing to high levels of total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), etc. Though many treatment techniques are being practiced, biotechnological methods are gaining importance. Biosorption is recognized as a cost‐effective technology worldwide; one potential sorbent being blue–green algae (BGA), for treating metal‐bearing effluents. This work studies the feasibility of using a species each of Spirulina , Oscillatoria , and Synechocystis , individually and as a consortium, as sorbents to remove Cr 3+ from a segregated stream, viz. exhaust chrome liquor (ECL) and synthetic BCS solution. The species studied were found to be effective in removing Cr 3+ considerably at varying concentrations, besides reducing sulfates, BOD, COD, etc. The results of ECL experiments were more encouraging than those for BCS solution. The kinetic data on Cr 3+ sorption onto algal biomass fit well into the pseudo‐second order model. The equilibrium data were analyzed using the classic Langmuir and Freundlich isotherm models, yielding good fits. The results of the experiments indicate that algal consortia could be good alternatives to the conventional treatment methods for leather and other industrial wastewaters containing chromium.