Influence of light intensity and tannery wastewater concentration on biomass production and nutrient removal by microalgae Scenedesmus sp.

Due to the absorption capacity of nutrients by microalgae, their uses for industrial wastewater treatment have shown increasing interest in research. Tannery wastewaters have high organic content and are rich in nitrogenous compounds which are essential for microalgae cultivation. Thus, the aim of this study was to use tannery wastewater as alternative cultivation medium for microalgae biomass production aiming to treat this effluent. Biomass production and removal of ammoniacal nitrogen, phosphorus and chemical oxygen demand by the microalgae Scenedesmus sp., cultivated in tannery wastewater, was studied under different wastewater concentrations (between 20% and 100%), light intensity (between 80 and 200 μmol photons m−2  s−1) at temperature of 25 °C and constant aeration. The results showed that the adaptation of microalgae for this nutrient source was effective. The cultivation of Scenedesmus sp. showed maximum biomass concentration (0.90 g L−1) and maximum removal of ammoniacal nitrogen (85.63%), phosphorus (96.78%) and COD (80.33%) at a tannery wastewater of 88.4% and light intensity of 182.5 μmol photons m−2 s−1.