title: Excess cell mass as an internal carbon source for biological denitrification.
abstract: Aim of the present work was to examine whether the SCOD (soluble chemical oxygen demand) released after the physical disruption of excess activated sludge can be used as an alternative carbon source for biological denitrification. In the first stage of research, we investigated the potential use of energy efficient hydrodynamic cavitation (HC) technique for the disruption of activated sludge. In a comparative study between ultrasonic cavitation (UC) and HC, it was observed that UC needs five times more energy than that of HC to release the same amount of SCOD. In the second stage of the experimental study, SCOD was successfully used as an alternative carbon source (alternative to sodium acetate) for biological denitrification. The critical weight ratio (SCOD/NO(3)-N) of seven ensured 100% removal of nitrate. Nitrate removal kinetics indicated that denitrification with SCOD as a carbon source gives higher specific denitrification rate (by approximately 200%) as compared to conventional carbon source (sodium acetate).
authors.affiliation: Chemical Engineering Department, Institute of Chemical Technology, University of Mumbai, Matunga, Mumbai 400 019, India.
authors.forename: Prashant M
authors.initials: PM
authors.lastname: Biradar
authors.forename: S B
authors.initials: SB
authors.lastname: Roy
authors.forename: S F
authors.initials: SF
authors.lastname: D'Souza
authors.forename: A B
authors.initials: AB
authors.lastname: Pandit
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods*; D002244:Carbon / Q000737:chemistry*; D007700:Kinetics; D009566:Nitrates / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012722:Sewage / Q000382:microbiology; D019346:Sodium Acetate / Q000737:chemistry; D013997:Time Factors; D014465:Ultrasonics; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods
chemical_list: D009566:Nitrates; D012722:Sewage; D014874:Water Pollutants, Chemical; D019346:Sodium Acetate; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen