A novel start-up strategy for mixotrophic denitrification biofilters by rhamnolipid and its performance on denitrification of low C/N wastewater. (January 2020)

• Record Type: Journal Article
• Authors: Peng, Chong; Huang, Hui; Gao, Yilin; Fan, Xuan; Peng, Pengcheng; Zhang, Xuxiang; Ren, Hongqiang
• Is Part Of: Chemosphere. Volume 239(2020)
• Publication Date: 2020-01
• Subjects: Mixotrophic denitrification biofilters (mDNBFs) -- Start-up -- Rhamnolipid -- Low C/N wastewater; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.124726
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A novel start-up strategy for sulfur-based mixotrophic denitrification biofilters (mDNBFs) by rhamnolipid was investigated for the first time. Rhamnolipid with gradient concentrations (0–120 mg/L) was added into five lab-scale mDNBFs. Results showed that rhamnolipid could promote biomass yield and nitrogen removal rate (NRR) by 71.7% and 68.7%, respectively, while its effect on EPS and adhesion force was concentration-dependent. The spatial distribution characteristics of microbial communities demonstrated the enrichment of main heterotrophic denitrifying bacteria outcompeted that of the autotrophs, with a more pronounced difference in high concentration rhamnolipid-treated mDNBFs. Furthermore, highest abundance of napA, narG, nirK and nosZ genes was observed in 80 mg/L rhamnolipid-treated mDNBF. Interfacial processes including solubilizing effect and hydration repulse and variations of organics were discussed to explicate the underlying mechanism. The study enlightened that an appropriate concentration (∼80 mg/L) of rhamnolipid may be a good solution for accelerating biofilm formation and enriching denitrifying bacteria to promote denitrification performance of mDNBFs treating low C/N wastewater. Graphical abstract: Image 1 Highlights: A start-up strategy for mDNBFs by rhamnolipid was first reported. Increased biomass and nitrogen removal rate by 71.7% and 68.7% in average in rhamnolipid-treated mDNBFs. Concentration-dependent effect of rhamnolipid on EPS secretion and adhesion force was observed. Enrichment of main heterotrophic denitrifying bacteria outcompeted that of the autotrophs. Interfacial process-mediated behavior influenced by rhamnolipid was discussed.