title: Impact of extraction methods on bio-flocculants recovered from backwashed sludge of bio-filtration unit.
abstract: Effect of ten extraction methods on flocculation activity and chemical composition of bio-flocculants recovered from backwashed sludge of bio-filtration unit was studied. The results showed that the chemical method was better than physical method with respect to the extracted BFs weight and its flocculation activity. Cell lysis did not affect to the flocculation activity of BFs. Among ten extraction methods, EDTA (20 g/L) was the best one with extracted BFs dry weight of 6242 mg/L and flocculation activity of 83%. Optimization of EDTA concentration showed that 5 g EDTA/L (or 0.2 g EDTA/g SS) was suitable for recovery of BFs from backwashed sludge. The flocculation activity of BFs was 94% when using 2.4 mg of BFs/g of kaolin. The outcome of this study suggested that backwashed sludge of the bio-filtration unit was a potential source for exploiting bio-flocculants.
authors.affiliation: Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam.
authors.forename: Viet Hoang
authors.initials: VH
authors.lastname: Nguyen
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada.
authors.forename: Nouha
authors.initials: N
authors.lastname: Klai
authors.affiliation: Institute of Environmental Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Hanoi, Viet Nam.
authors.forename: Thanh Dong
authors.initials: TD
authors.lastname: Nguyen
authors.affiliation: INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, G1K 9A9, Canada. Electronic address: Rd.tyagi@ete.inrs.ca.
authors.forename: Rajeshwar Dayal
authors.initials: RD
authors.lastname: Tyagi
mesh_terms: D004492:Edetic Acid / Q000737:chemistry; D005374:Filtration / Q000379:methods*; D005427:Flocculation; D005557:Formaldehyde / Q000737:chemistry; D007616:Kaolin / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D005557:Formaldehyde; D007616:Kaolin; D004492:Edetic Acid
keywords: Bio-flocculants; Flocculation activity; Recovery; Wastewater sludge