title: Valuation of OSA process and folic acid addition as excess sludge minimization alternatives applied in the activated sludge process.
abstract: The aim of this study was to investigate the ability of the oxic-settling-anaerobic (OSA)-process and the folic acid addition applied in the activated sludge process to reduce the excess sludge production. The study was monitored during two distinct periods: activated sludge system with OSA-process, and activated sludge system with folic acid addition. The observed sludge yields (Yobs) were 0.30 and 0.08 kgTSS kg(-1) chemical oxygen demand (COD), control phase and OSA-process (period 1); 0.33 and 0.18 kgTSS kg(-1) COD, control phase and folic acid addition (period 2). The Yobs decreased by 73 and 45% in phases with the OSA-process and folic acid addition, respectively, compared with the control phases. The sludge minimization alternatives result in a decrease in excess sludge production, without negatively affecting the performance of the effluent treatment.
authors.affiliation: Department of Sanitary and Environmental Engineering - UFSC/CTC/ENS, Campus Universitário - Trindade, Florianópolis, SC 88.010-970, Brazil E-mail: lavina8@hotmail.com.
authors.forename: C L
authors.initials: CL
authors.lastname: Martins
authors.affiliation: Department of Sanitary and Environmental Engineering - UFSC/CTC/ENS, Campus Universitário - Trindade, Florianópolis, SC 88.010-970, Brazil E-mail: lavina8@hotmail.com.
authors.forename: V F
authors.initials: VF
authors.lastname: Velho
authors.affiliation: Department of Sanitary and Environmental Engineering - UFSC/CTC/ENS, Campus Universitário - Trindade, Florianópolis, SC 88.010-970, Brazil E-mail: lavina8@hotmail.com.
authors.forename: S R A
authors.initials: SR
authors.lastname: Ramos
authors.affiliation: Superior Institute of Agronomy, Lisboa, Portugal.
authors.forename: A S C D
authors.initials: AS
authors.lastname: Pires
authors.affiliation: Superior Institute of Agronomy, Lisboa, Portugal.
authors.forename: E C N F A
authors.initials: EC
authors.lastname: Duarte
authors.affiliation: Department of Sanitary and Environmental Engineering - UFSC/CTC/ENS, Campus Universitário - Trindade, Florianópolis, SC 88.010-970, Brazil E-mail: lavina8@hotmail.com.
authors.forename: R H R
authors.initials: RH
authors.lastname: Costa
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005492:Folic Acid / Q000032:analysis* / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology; D018508:Water Purification / Q000379:methods*
chemical_list: D005492:Folic Acid; D012722:Sewage; D062065:Wastewater