Enhanced denitrification of dispersed swine wastewater using Ca(OH)2-pretreated rice straw as a solid carbon source. (October 2022)

• Record Type: Journal Article
• Authors: Yuan, Lianhua; Tan, Leilei; Shen, Zhiqiang; Zhou, Yuexi; He, Xuwen; Chen, Xuemin
• Is Part Of: Chemosphere. Volume 305(2022)
• Publication Date: 2022-10
• Subjects: Dispersed swine wastewater -- Ca(OH)2pretreatment -- Solid carbon source denitrification -- Rice straw -- Microbial community; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.135316
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In a pilot-scale packed bed reactor, the denitrification performance and microbial community structure of the dispersed swine wastewater treatment using calcium hydroxide (Ca(OH)2 ) pretreated rice straw as a carbon source were investigated. In a Ca(OH)2 -pretreated rice straw supported denitrification system (Ca(OH)2 -RS), the removal efficiency of NO3 − -N was 96.39% at an influent NO3 − -N load of 0.04 kg/(m 3 d). Meanwhile, there was no obvious accumulation of NO2 − -N or chemical oxygen demand (COD) in the effluent of Ca(OH)2 -RS. The contents of soluble microbial byproduct-like substances and tryptophan-like substances in the effluent of Ca(OH)2 -RS were reduced by 46.2% and 43.4%, respectively, compared with the influent. Overall, the Ca(OH)2 -pretreated rice straw system had a strong resistance to fluctuations in water quality conditions, such as influent NO3 − -N and COD concentrations. According to the microbial assay results, the Ca(OH)2 pretreatment enriched more denitrifying bacteria. Among them, Proteobacteria (42.33%) and Bacteroidetes (35.28%) were the dominant bacteria. Moreover, the main denitrifying functional bacteria, genera norank_f_Saprospiraceae (13.32%), norank_f_Porphyromonadaceae (4.22%), and Flavobacterium (3.25%), were enriched in Ca(OH)2 -RS. This suggested that using Ca(OH)2 -pretreated rice straw as a carbon source was a stable and efficient technology to enhance the denitrification performance of dispersed swine wastewater. Graphical abstract: Image 1 Highlights: Swine wastewater was treated through denitrification process. Ca(OH)2 -pretreated rice straw enhanced denitrification performance. Ca(OH)2 -RS had strong resistance to the fluctuation of influent NO3 − -N and COD. Higher abundant denitrifiers bacteria in Ca(OH)2 -RS.