Abstract:
This research examined the effects of flocculating agents and their varying concentration on enhancing the aggregation and growth of algae. Four species of algae, Spirulina platensis, Cholorella vulgaris, Scenedesmus acutus and Closterium acerorum. were selected for this study. The flocculating agents used were potassium aluminium sulphate, ferri chloride, sodium hydroxide and magnesium hydroxide at five concentration : 50 ppm., 100 ppm., 150 ppm., 200 ppm. and 250 ppm., respectively. It was found that the concentration and kinds of flocculating agents used enhanced of aggregation of algae. Ferri chloride produced the best result among all of the agents while, in consecutive order, potassium aluminium sulphate, sodium hydroxide and magnesium hydroxide were less effective. The amount of harvested of algae increased when the concentration of flocculating agents was increased. It. was also found that the growth of algae after they were harvested was different. The flocculent of Spirulina platensis produced by ferric chloride at the concentration 100 ppm. grew more successfully than when other flocculating agents were used. The flocculent of Scenedesmus acutus produced by potassium aluminium sulphate at a concentration of 100 ppm. grew better than that obtained when other agents were introduced to the algae. The flocculent of Chlorella vulgaris grew best when magnesium hydroxide was used at a concentration of 50 ppm. Finally, the flocculent of Closterium acerorum produced the greatest amount of algae growth when sodium hydroxide was used at a concentration of 150 ppm. The resultant aggregation of algae by these flocculating agents did not show any effects on the growth algae following the aggregation.