Format

Send to

Choose Destination
Water Res. 2019 Dec 1;166:115038. doi: 10.1016/j.watres.2019.115038. Epub 2019 Sep 5.

Long term performance and dynamics of microbial biofilm communities performing sulfur-oxidizing autotrophic denitrification in a moving-bed biofilm reactor.

Author information

1
Department of Civil and Environmental Engineering, Water Technology Center, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch), The Hong Kong University of Science and Technology, Hong Kong China; Shenzhen Research Institute, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China.
2
Department of Civil and Environmental Engineering, Water Technology Center, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch), The Hong Kong University of Science and Technology, Hong Kong China.
3
Department of Biotechnology, Delft University of Technology, Delft, the Netherlands.
4
Department of Civil and Environmental Engineering, Water Technology Center, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch), The Hong Kong University of Science and Technology, Hong Kong China; Shenzhen Research Institute, Fok Ying Tung Graduate School, The Hong Kong University of Science and Technology, Guangdong, China. Electronic address: cewudi@ust.hk.

Abstract

Sulfide-oxidizing autotrophic denitrification (SOAD) implemented in a moving-bed biofilm reactor (MBBR) is a promising alternative to conventional heterotrophic denitrification in mainstream biological nitrogen removal. The sulfide-oxidation intermediate - elemental sulfur - is crucial for the kinetic and microbial properties of the sulfur-oxidizing bacterial communities, but its role is yet to be studied in depth. Hence, to investigate the performance and microbial communities of the aforementioned new biosystem, we operated for a long term a laboratory-scale (700 d) SOAD MBBR to treat synthetic saline domestic sewage, with an increase of the surface loading rate from 8 to 50 mg N/(m2·h) achieved by shortening the hydraulic retention time from 12 h to 2 h. The specific reaction rates of the reactor were eventually increased up to 0.37 kg N/(m3·d) and 0.73 kg S/(m3·d) for nitrate reduction and sulfide oxidation with no significant sulfur elemental accumulation. Two sulfur-oxidizing bacterial (SOB) clades, Sox-independent SOB (SOBI) and Sox-dependent SOB (SOBII), were responsible for indirect two-step sulfur oxidation (S2-→S0→SO42-) and direct one-step sulfur oxidation (S2-→SO42-), respectively. The SOBII biomass-specific electron transfer capacity could be around 2.5 times greater than that of SOBI (38 mmol e-/(gSOBII·d) versus 15 mmol e-/(gSOBI·d)), possibly resulting in the selection of SOBII over SOBI under stress conditions (such as a shorter HRT). Further studies on the methods and mechanism of selecting of SOBII over SOBI in biofilm reactors are recommended. Overall, the findings shed light on the design and operation of MBBR-based SOAD processes for mainstream biological denitrification.

KEYWORDS:

Autotrophic denitrification; Mainstream nitrogen removal; Microbial competition; PICRUSt; Sulfur-oxidizing bacteria

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center