Cost-effective tannery wastewater treatment using cyanobacteria: insights on the growth pattern and seedling vigor...

Nowadays to cope-up with the emerging global clean-water crisis, wastewater needs to be remediated properly to be used as an alternative source. Here a cost-effective approach has been taken to treat heavily-polluted (BOD-1234.33 mg L^-1, COD-1706.64 mg L^-1, TDS-6984 mg L^-1, and sulfide-140.8 mg L^-1 ammonium-134.5 mg L^-1) Tannery Waste Water (TWW). Three cyanobacteria were (Arthrospira platensis, Leptolyngbyavalderiana, and Anabaenasphaerica) used as bio-reagents in pilot-scale treatment. Wastewater remediation-potential and biomass-generation capacity were evaluated in various TWW concentrations. The maximum biomass growth and the highest pollution removal percentage was observed when exposed to 50% TWW; although among the tested strain, Arthrospira and Leptolyngbya performed better than Anabaena by showing greater pollution removal potential (BOD 93%, COD 94%, sulfide 99%, ammonium 93%) in one hand and higher biomass production rate (100 mg L^-1 Day^-1) on the other. DO was increased noticeably by 10-15-fold. Morphological characterizations of tannery wastewater exposed Anabaena revealed unusual thick sheath formation, along with heterocyst and akinete formation in their trichome. Biochemical characterizations of remediating cyanobacteria showed presence of wastewater-accumulated nutrients (N, P, K). Nutrient-loaded biomass improved growth of rice and chickpea seedlings when used as a growth promoter. These facts have been illustrated by factor analysis and discriminant analysis. Cyanobacteria-mediated pilot-scale tannery wastewater treatment would create ecologically and economically-sustainable technology for clean-water production.

The online version contains supplementary material available at 10.1007/s13205-023-03712-x.