Document Type : Original Article
Department of Environmental Management, Kaduna State University, Kaduna, Nigeria
The tanning, textile, and dye industries consume a large amount of water during production, leading to a large quantity of wastewater. This study aims to provide insight into the phycoremediation of the tannery, textile, and dye wastewater microalgae biofilm. Microalgae biofilm was grown in a photo-bioreactor with BG-11 as the culture medium, used to treat tannery, textile, and dye wastewater. The antioxidant response of the microalgae biofilm before and after treatment of the wastewater was determined. The results obtained show the microalgae biofilm best reduced biochemical oxygen demand (BOD) (68%), chemical oxygen demand (COD) (83%), chloride (52%), phenol (39%), and alkalinity (47%), from textile wastewater, Total dissolve solids (TDS) (88%), total suspended solids (TSS) (94%), sulfate (56%), phosphate (45%), total nitrogen (63%), oil and grease (42%), and total chromium (64%) were all reduced in dyeing wastewater, while electrical conductivity (EC) (64%) and total chromium were reduced the best in tannery wastewater. The result also shows an increase in peroxidase activity, catalase activity, superoxide dismutase activity (SOD), and glutathione reductase activity, indicating the role of enzymatic antioxidants in pollutant degradation and counteracting the effect of reactive oxygen species (ROS). The decrease in flavonoid, anthocyanin, and carotenoid indicates non-enzymatic antioxidants' involvement in the degradation and role of the pollutant in osmoregulatory balance maintenance. Simultaneously, the increase in TOC and lipid content signifies the strong role of antioxidants in radical scavenging. The increase in phosphomolybdate capacity, hydrogen peroxide scavenging, and DPPH scavenging ability is also a strong indication of high ROS production and prevention of its effect. The microalgae biofilm's ability to remove pollutants from wastewater is by the activities of enzyme release by the microalgae or adsorption of the pollutants to the wall of the participant microalgae in the biofilm.