Perchlorate bioreduction in UASB reactor: S^2--autotrophic granular sludge formation and sulphate generation control

ABSTRACT

Perchlorate (${\mathrm{ClO}}_4^{-}$) industrial wastewater requires efficient removal to prevent adverse environmental impacts, however, high concentration and low biodegradability give rise to poor ${\mathrm{ClO}}_4^{-}$ bioreduction performance. ${\mathrm{S}}^{2-}$-autotrophic granular sludge (${\mathrm{S}}^{2-}$-AuGS) was firstly cultivated for high concentration perchlorate (${\mathrm{ClO}}_4^{-}$) removal in the upflow anaerobic sludge blanket (UASB) reactor (${\mathrm{ClO}}_4^{-}$: 150 mg L⁻¹). Simultaneously, the ${\mathrm{S}}^{2-}$ was utilized to control the ${\mathrm{SO}}_4^{2-}$ generation as electron donor, the effluent ${\mathrm{SO}}_4^{2-}$ concentration (190 mg L⁻¹) was satisfied with drinking water standard (250 mg L⁻¹). Under the optimized condition of hydraulic retention time (HRT) (6 h) and ${\mathrm{S}}^{2-}$/${\mathrm{ClO}}_4^{-}$ molar ratio (2.2), more EPS was secreted, which promoted the $S^{2-}$-AuGS formation and stability. Though acclimation of 146 d, the ${\mathrm{S}}^{2-}$-AuGS was formed with a large average granular sludge size (612 μm) and an excellent settleability (sludge volume index: SVI₅/SVI₃₀= 1). With the mature ${\mathrm{S}}^{2-}$-AuGS formation, the highest ${\mathrm{ClO}}_4^{-}$ and ${\mathrm{S}}^{2-}$ loading was increased to 1.06 and 0.75 kg m⁻³ d⁻¹. Interestingly, Georgfuchsia, Methyloversatilis, Sulfurisoma, and Exiguobacterium were the main microbial community in the ${\mathrm{S}}^{2-}$-AuGS. This study proposed to form a novel ${\mathrm{S}}^{2-}$-AuGS for developing the high ${\mathrm{ClO}}_4^{-}$ concentration removal performance and to utilize the ${\mathrm{S}}^{2-}$ as an electron donor for controlling the excessive ${\mathrm{SO}}_4^{2-}$ generation.

GRAPHICAL ABSTRACT

KEYWORDS:

• Perchlorate bioreduction
• ${\mathrm{S}}^{2-}$-autotrophic
• granular sludge
• sulphate generation
• UASB reactor

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary materials.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [Grant Numbers 51678387, 51708389], Scientific Research Project of Tianjin Municipal Education Commission [Grant Number 2020KJ040], and Key Project of Natural Science Foundation of Tianjin City [Grant Number: 18JCZDJC40000].