Abstract
Background: High salinity (1–10% w/v) of tannery wastewater makes it difficult to be treated by
conventional biological treatment. Salt tolerant microbes can adapt to these saline conditions and
degrade the organics in saline wastewater.
Results: Four salt tolerant bacterial strains isolated from marine and tannery saline wastewater
samples were identified as Pseudomonas aeruginosa, Bacillus flexus, Exiguobacterium homiense and
Staphylococcus aureus. Growth factors of the identified strains were optimized. Tannery saline
wastewater obtained from a Common Effluent Treatment Plant (CETP) near Chennai (southern
India) was treated with pure and mixed consortia of four salt tolerant bacterial strains. Experiments
with optimized conditions and varying salt content (between 2 and 10% (w/v) were conducted. Salt
inhibition effects on COD removal rate were noted. Comparative analysis was made by treating
the tannery saline wastewater with activated sludge obtained from CETP and with natural habitat
microbes present in raw tannery saline wastewater.
Conclusion: Salt tolerant bacterial mixed consortia showed appreciable biodegradation at all
saline concentrations (2%, 4%, 6%, 8% and 10% w/v) with 80% COD reduction in particular at 8%
salinity level the consortia could be used as suitable working cultures for tannery saline wastewater
treatment.
Background
Tannery saline wastewater, a primary effluent stream in
leather processing industry is generated by soaking