Effect of low-intensity electric current field and iron anode on biological nitrate removal in wastewater with low COD to nitrogen ratio from coal pyrolysis. (June 2020)

• Record Type: Journal Article
• Authors: Zhang, Zhengwen; Xu, Chunyan; Han, Hongjun; Zheng, Mengqi; Shi, Jingxin; Ma, Wencheng
• Is Part Of: Bioresource technology. Volume 306(2020)
• Publication Date: 2020-06
• Subjects: Wastewater from coal pyrolysis (WCP) -- Microbial electrolysis cell (MEC) -- Mixotrophic nitrate removal -- Iron anode -- Microbial community analysis; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2020.123123
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: Nitrate removal in wastewater from coal pyrolysis was enhanced by iron anode MEC. Production of N2 O was decreased by the formation of Fe 2+ . Extra nitrate removed was performed by nitrate reducing ferrous oxidation bacteria. The interaction of functional bacteria established an iron cycle in iron anode MEC. Abstract: Mixotrophic nitrate removal in wastewater from coal pyrolysis was achieved in microbial electrolysis cell with iron anode (iron-MEC). The effect of voltage, iron anode and conductivity were investigated. The effluent TN concentration was 8.35 ± 1.94 mg/L in iron-MEC when the conductivity of the wastewater was adjusted to 3.97 ± 0.08 mS/cm, which was lower than that in no-treated reactor. The increase of current density, which was resulted from the elevation of conductivity, promoted the iron corrosion and Fe 2+ ion generation. Therefore, more Fe 2+ ion was utilized by nitrate reducing ferrous oxidation bacteria (NRFOB) used to reduce nitrate. The microbial community analysis demonstrated that NRFOB, including Acidovorax and Bradyrhizobium, possessed a higher abundance in iron-MEC. The enrichment of Geobacter in iron-MEC might imply that the part of Fe(III) produced by ferrous oxidation was reduced by Geobacter, which established an iron cycle. Moreover, the production of N2 O was decreased by the formation of Fe 2+ ion.