Performance of a recirculating aquaculture system using biofloc biofilters with convertible water-treatment efficiencies

Wenchang Liu; Xinze Du; Hongxin Tan; Jing Xie; Guozhi Luo; Dachuan Sun

doi:10.1016/j.scitotenv.2020.141918

Performance of a recirculating aquaculture system using biofloc biofilters with convertible water-treatment efficiencies

Sci Total Environ. 2021 Feb 1:754:141918. doi: 10.1016/j.scitotenv.2020.141918. Epub 2020 Sep 2.

Authors

Wenchang Liu¹, Xinze Du², Hongxin Tan³, Jing Xie⁴, Guozhi Luo², Dachuan Sun²

Affiliations

¹ Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai Science and Technology Committee, Shanghai 201306, China; Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai Ocean University, Shanghai Science and Technology Committee, Shanghai 201306, China.
² Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai Science and Technology Committee, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, (Shanghai Ocean University), Shanghai 201306, China.
³ Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai Science and Technology Committee, Shanghai 201306, China; Shanghai Collaborative Innovation for Aquatic Animal Genetics and Breeding, (Shanghai Ocean University), Shanghai 201306, China. Electronic address: hxtan@shou.edu.cn.
⁴ Shanghai Aquatic Products Processing and Storage Engineering Technology Research Center, Shanghai Ocean University, Shanghai Science and Technology Committee, Shanghai 201306, China.

PMID: 32911144
DOI: 10.1016/j.scitotenv.2020.141918

Abstract

To achieve high water-treatment efficiencies and simplify the setup of recirculating aquaculture systems (RAS), this study examined the use of suspended growth reactors (R1 and R2) based on biofloc technology (BFT) as water-treatment biofilters. Moreover, the conversion of the heterotrophic R1 biofilter to a nitrifying role was investigated. During RAS operation using heterotrophic BFT biofilters, R1 and R2 simultaneously controlled total ammonium nitrogen, nitrite (NO₂^--N), nitrate (NO₃^--N), soluble reactive phosphate (SRP), and alkalinity, with relevant functional microbes including denitrifying bacteria (DNB), phosphorus accumulating organisms (PAOs), denitrifying PAOs (DNPAOs), glycogen accumulating organisms, ammonia oxidizing bacteria, and nitrite oxidizing bacteria. To achieve low concentrations of nitrogen, phosphorus, and save carbon sources, we were able to quickly convert R1 into a nitrifying BFT biofilter by stopping carbohydrate addition. Although there were dominant relative abundances of DNB, PAOs, and DNPAOs in the converted R1, the lack of carbon sources resulted in continuous rise of NO₃^--N in the effluent, stable NO₂^--N removal efficiency, and absence of SRP removal after 40 h. However, R2 retained the previous NO₃^--N and SRP removal efficiencies with carbohydrate addition. This indicated that this novel RAS using BFT biofilters achieved simultaneous nitrogen and phosphate removal, and that the convertible water-treatment efficiencies of BFT biofilters could be controlled by carbohydrate addition. This approach could simplify the RAS setup and meet real-time water quality demands.

Keywords: Denitrification; Microbial community; Nitrification; Phosphate removal; Scortum barcoo.

MeSH terms

Aquaculture
Bioreactors
Denitrification
Nitrification*
Nitrogen / analysis
Wastewater
Water Purification*

Substances

Waste Water
Nitrogen