Investigation of transient forms of sulfur during biological treatment of spent caustic. Issue 12 (18th June 2018)

• Record Type: Journal Article
• Authors: Kalantari, Hamed; Nosrati, Mohsen; Shojaosadati, Seyed Abbas; Shavandi, Mahmoud
• Is Part Of: Environmental technology. Volume 39:Issue 12(2018)
• Page Start: 1597
• Page End: 1606
• Publication Date: 2018-06-18
• Subjects: Spent caustic -- haloalkaliphiles -- sulfide -- Thioalkalivibrio versutus -- biological treatment; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2017.1334707
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: In the present study, the production of various transient forms of sulfur during biological oxidation of sulfidic spent caustics under haloalkaline conditions in a stirred tank bioreactor is investigated. Also, the effects of abiotic aeration (chemical oxidation), dissolved oxygen (DO) concentration and sodium concentration on forms of sulfur during biological treatment are demonstrated. Thioalkalivibrio versutus strain was used for sulfide oxidation in spent caustic (SC). The aeration had an important effect on sulfide oxidation and its final products. At DO concentrations above 2 mg l −1, majority of sulfide was oxidized to sulfate. Maximum sulfide removal efficiency (%R) and yield of sulfate production was obtained in Na + concentration ranging from 0.6 to 2 M. Abiotic aeration, which is the most important factor of production of thiosulfate, resulted in the formation of an undesired product-polysulfide. However, abiotic aeration can be used as a pretreatment to biological treatment. In the bioreactor the removal efficiency was obtained as 82.7% and various forms of sulfur such as polysulfide, biosulfur, thiosulfate and sulfate was observed during biological treatment of SC.