A pilot-scale study of a novel two-stage denitrification filter. (February 2021)

• Record Type: Journal Article
• Authors: Guo, Qiming; Yang, Zhihong; Zhao, Qun; Chen, Jing; Li, Jie; Chen, Lijun; Shi, Wei; An, Pinglin; Wang, Guanping; Xu, Guangjing
• Is Part Of: Journal of water process engineering. Volume 39(2021)
• Publication Date: 2021-02
• Subjects: Sponge iron -- Volcanic rock -- Fe(II)-oxidizing nitrate-reducing bacteria -- Dissolved oxygen -- External carbon source; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2020.101873
• Languages: English
• ISSNs: 2214-7144

Abstract

Abstract: In this study, a pilot-scale two-stage denitrification filter (TSDNF) was developed to further remove the effluent nitrate from a cyclic activated sludge system. Sponge iron and volcanic rock were used as DNF-1 and DNF-2 filter beds, respectively. A single-stage DNF-3 filter with volcanic rock was used as the control. Most dissolved oxygen (DO) was consumed for iron oxidation in the DNF-1, and in turn denitrification rates increased in the DNF-2. In the DNF-1, 17.9 %±13.6 % of the NO3 − -N was removed in the absence of organic carbons, resulting in a significant increase in the total NO3 − -N removal in the TSDNF with a COD/NO3 − -N ratio of about 2.6. Autotrophic denitrification should be finished by the dominant Fe(II)-oxidizing nitrate-reducing Gallionellaceae genus (21.38 %) in the DNF-1, while common denitrifying strains were dominant in both DNF-2 and DNF-3. Moreover, obvious chemical phosphorus removal (83.3 %) was found in the DNF-1. Therefore, simultaneous autotrophic denitrification and chemical P-removal can be achieved using iron ions released from sponge iron filters, which provides a new model to reshape the design of advanced removal of nitrogen and phosphorus in the secondary clarifier effluent.