REMOVALS OF CHAIN-LIKE AND PIN-LIKE ALGAE BY POSITIVELY CHARGED BUBBLE FLOTATION
Keywords:algal morphology, filamentous algal removal, bubble flotation, positively charged bubble.
The objective of this study was to investigate the effects of positive ferric-bubble on behaviors of chain-like and pin-like algae (i.e. Phormidium specie (sp.) and Nitzchia pungens, respectively). Two selected algae were cultured in a laboratory under the certain conditions. At stationary phase, algae were below 4 μm in diameter and in the range of 50 ~ 100 μm for chain-like algae, of 20 – 35 μm for pin-like shape in length; with negatively charged at cultivated conditions (pH from 6.5 to 9). Positive ferric-bubbles were generated by adding coagulants (as Fe3+) and were injected at a pressure of 5 bars with a bubble rate of 30 % into a 10 L-acryl made reactor with algal-containing tap water. Removal efficiencies were assessed by the cells number, Chlorophyll a reduction and the morphological changes (i.e. cell structure). For cells number, about 90 % of both algae were removed whilst pin-like algae obtained the higher reduction of Chlorophyll a, showing by 92 % in comparison with about 85 % of chain-like shape. The breakup of algal morphologies occurred for chain-like cells only. The structure of filaments affects performance of positively charged bubble flotation.