Biorefinery from tannery wastewater treatment: a preliminary analysis

Abstract

The leather processing generates large amounts of wastewater which have high concentrations of organic matter, nutrients and toxic chemicals. Before the possibility of using wastewater as a low-cost culture medium of cyanobacteria to obtain bioproducts in biorefinery, the aim of this study was to evaluate the cyanobacteria Aphanothece microscopica Nägeli cultivation potential in tannery wastewater for the production of biomass, as well as its applicability in the treatment of these effluents. To achieve this, the cyanobacteria cultures were conducted in tannery wastewater in a heterotrophic bioreactor under conditions of initial celular concentration of 200 mg L^-1, initial pH 7.6, temperature of 25 ºC, continuous aeration and absence of light., During the studies, the kinetics of cyanobacteria growth in the effluent and the percentages of removal of the chemical oxygen demand, total phosphorus and Kjeldahl total nitrogen from the effluent after cultivation were analyzed. The results indicated the feasibility of the use of the cyanobacteria, in heterotrophic bioreactor, for the tannery wastewater treatment allied with biomass production, being registered a biomass productivity of 42.67 mg L^-1 h^-1 and  removal efficiencies of 72.3% of chemical oxygen demand, 94.7% of total phosphorus and 51.9% of total Kjeldahl nitrogen, after 36 hours of cultivation.