title: Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors.
abstract: Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4(2-) ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing bioreactors. The sulfide was measured using a sulfide ion selective electrode (pS) and the values obtained were used to calculate proportional-integral-derivative (PID) controller parameters. The experiments were performed in an inverse fluidized bed bioreactor with automated operation using the LabVIEW software version 2009(®). A rapid response and high sulfide increment was obtained through a stepwise increase in the CODin concentration, while a stepwise decrease to the HRT exhibited a slower response with smaller sulfide increment. Irrespective of the way the OLR was decreased, the pS response showed a time-varying behavior due to sulfide accumulation (HRT change) or utilization of substrate sources that were not accounted for (CODin change). The pS electrode response, however, showed to be informative for applications in sulfate reducing bioreactors. Nevertheless, the recorded pS values need to be corrected for pH variations and high sulfide concentrations (>200 mg/L).
authors.affiliation: Chair Group Pollution Prevention and Resource Recovery, UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands. Electronic address: denyskristalia@hotmail.com.
authors.forename: D K
authors.initials: DK
authors.lastname: Villa-Gomez
authors.affiliation: Chair Group Pollution Prevention and Resource Recovery, UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Cassidy
authors.affiliation: Systems and Control Group, Wageningen University, P.O. Box 17, 6700 AA Wageningen, The Netherlands.
authors.forename: K J
authors.initials: KJ
authors.lastname: Keesman
authors.affiliation: Sub-Department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Sampaio
authors.affiliation: Chair Group Pollution Prevention and Resource Recovery, UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, The Netherlands.
authors.forename: P N L
authors.initials: PN
authors.lastname: Lens
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D017736:Ion-Selective Electrodes; D009930:Organic Chemicals / Q000032:analysis; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D009930:Organic Chemicals; D013431:Sulfates; D013440:Sulfides
keywords: Bioreactor; Control; Organic loading rate; Sulfide; pS