Application of chitosan as a flocculant for the cultures of the green alga: Scenedesmus acutus.

Use of partially deacetylated chitin or chitosan (CSN) has been investigated
as a potential cationic flocculant to concentrate the cultures of the alga
ScenedesrnU$ acutus, The optimal concentration of 0.05 gil of chitosan could
flocculate mass outdoor cultures with 6.3 times less energy inputs and minimal
operation conditions compared to the use of desired centrifugal separator. Under
comparable viscous resistance conditions, laboratory experiments were carried out
using different flocculants, viz" C8N in CH3COOH, Ca(OH)2, KAl(S04)!
Al~(SO')3 for their sedimentation rates. Chitosan gave a maximum value of 96.5 0/0
fall in algal cell concentration of the culture supernatant within 10 min compared
to all the other flocculants tested. The optimum OD range for flocculation was
found to be between 0,4 to 0.5 and pH 7.5 to 8.5. Since chitosan is a natural
product and carbohydrate in nature, it appeats to have greater potential in
concentration of algae in mass cultures without affecting the toxicological safety.