IMPACT OF INDUSTRIAL DYES ON ALGAL GROWTH

The deterioration of water quality because of industrial dye discharges is becoming an emerging environmental problem throughout the world. Dyes are directly discharged into nearby water bodies which in turn affect the aquatic ecosystem and human health. Dyes were degraded by means of biological methods. This study involves the application of two algae (Chlorella vulgaris and Spirulina) and oxidation pond in the decolourisation of dyes. The UV spectromax M3 spectrophotometer was used in reading absorbance values. Methylene blue (MB) (20 mg/l, 50 mg/l and 100mg/l), Eriochrome Black T (EBT) (20mg/l, 50mg/l and 100mg/l) and Melanoidin (100mg/l, 250mg/l and 500mg/l) at different concentrations were used for this study. Decolourisation was recorded in a 10-day experiment. In Spirulina, maximum dye removal was 92.37 percent (20mg/l) in methylene blue dye, 54.24 percent (20 mg/l) in EBT and 45.89percent (100mg/l) in melanoidin while in oxidation pond, the maximum dye removal was 91.84 percent (20mg/l) in methylene blue dye, 93.22percent (20mg/l) in EBT and 46.1 percent (100mg/l) in melanoidin and in Chlorella vulgaris, the maximum dye removal was 91.3 percent (20mg/l) in methylene blue dye, 79.25 percent (20mg/l) in EBT and 57 percent (100mg/l) in melanoidin. The dye removal was dependent on algal concentration and dye concentration. Gel puncture method was used to determine the toxicity of individual dyes on algae (Mixed sample, Scenedesmus and Lake Sample) at varying concentration of dyes.