Effective dampening of temperature effects in an anammox reactor treating real mainstream wastewater. (April 2021)

• Record Type: Journal Article
• Authors: Juan-Díaz, Xènia; Pérez, Julio; Carrera, Julián
• Is Part Of: Journal of water process engineering. Volume 40(2021)
• Publication Date: 2021-04
• Subjects: Mainstream anammox -- Urban wastewater -- Overcapacity -- Substrate concentration profiles; Water-supply engineering -- Periodicals; Saline water conversion -- Periodicals; Seawater -- Distillation -- Periodicals; Sanitary engineering -- Periodicals; Sewage -- Purification -- Periodicals; 627
• DOI: 10.1016/j.jwpe.2020.101853
• Languages: English
• ISSNs: 2214-7144

Abstract

Graphical abstract: Highlights: The up-flow anammox sludge bed reactor is able to treat real mainstream wastewater. Up-flow anammox sludge bed allows dampening the effect of 10 °C temperature drop. Heterogeneous substrate distribution granted assistance of intra-bed overcapacity. Intra-bed reactor overcapacity allows constant loading rates over the seasons. Despite influent COD, anammox conversion dominates over heterotrophic even at 10 °C. Abstract: The aim of the present study was to evaluate the capability of an up-flow anammox sludge bed reactor (13 L) of dampening a 10 °C temperature drop at mainstream conditions while operating at constant nitrogen loading rates (0.11 ± 0.01 g N L −1 d −1 ). The up-flow anammox sludge bed reactor was fed with an aerobically pre-treated mainstream wastewater. The reactor temperature was controlled as to mimic a (realistic) summer-to-winter transition from 20 to 10 °C plus a three months period at 10 °C. During the 350 days of operation, the average nitrogen removal rate remained high (0.10 ± 0.01 g N L −1 d −1 ), indicating that the 10 °C drop did not affect the overall efficiency of the reactor. This can be explained as anammox activity differed among the different sludge bed sections. At 20 °C, anammox activity was mainly located at the bottom of the sludge bed. At 10 °C, the anammox activity decrease of the bottom sludge bed was compensated by an activity increase within the upper sludge bed sections. The contribution of heterotrophic denitrifying activity to the total nitrogen removal rate was assessed to be 3-to-5 times lower than that of anammox, even at 10 °C. Microbial community of 16S rRNA gene-targeted sequencing analyses resulted in the identification of an uncharacterized Planctomycetes in high numbers. This study demonstrated that the low temperatures should not be an obstacle for the feasibility of anammox bacteria in the main water line of an urban wastewater treatment plant.