title: Heterotrophic and elemental-sulfur-based autotrophic denitrification processes for simultaneous nitrate and Cr(VI) reduction.
abstract: Nitrate and chromate can be present together in water resources as nitrate is a common co-contaminant in surface and ground waters. This study aims at comparatively evaluating simultaneous chromate and nitrate reduction in heterotrophic and sulfur-based autotrophic denitrifying column bioreactors. In sulfur-based autotrophic denitrification process, elemental sulfur and nitrate act as an electron donor and an acceptor, respectively, without requirement of organic supplementation. Autotrophic denitrification was complete and not adversely affected by chromate up to 0.5 mg/L. Effluent chromate concentration was <50 μg/L provided that influent chromate concentration was ≤0.5 mg/L. Heterotrophic denitrification performance was not adversely affected even at 20 mg/L chromate and complete chromate reduction was attained up to 10 mg/L. Although autotrophic denitrification rate was much lower compared with heterotrophic one, it may be preferred in drinking water treatment due to the elimination of organic supplementation and the risk of treated effluent contamination.
authors.affiliation: Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul, Turkey. Electronic address: erkansahinkaya@yahoo.com.
authors.forename: Erkan
authors.initials: E
authors.lastname: Sahinkaya
authors.affiliation: Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa, Turkey; Yeditepe Treatment Company, Kucukbakkalkoy, Ataşehir, Istanbul, Turkey.
authors.forename: Adem
authors.initials: A
authors.lastname: Kilic
mesh_terms: D052818:Autotrophic Processes; D001419:Bacteria / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology; D002857:Chromium / Q000302:isolation & purification*; D058440:Denitrification; D052836:Heterotrophic Processes; D009566:Nitrates / Q000302:isolation & purification*; D013455:Sulfur / Q000378:metabolism*; D014865:Waste Disposal, Fluid
chemical_list: D009566:Nitrates; D002857:Chromium; C074702:chromium hexavalent ion; D013455:Sulfur
keywords: Autotrophic denitrification; Chromate removal; Elemental sulfur; Heterotrophic denitrification; Nitrate removal