Accelerated start-up, long-term performance and microbial community shifts within a novel upflow porous-plated anaerobic reactor treating nitrogen-rich wastewater via ANAMMOX process.

Dachao Zhang,Jianzheng Li,Zuwen Liu,Frederick Ayivi,Wuhui Luo,Shi Xu,Philip Antwi,Longwen Xiao,Hao Su,Cheng Lai

doi:10.1039/c9ra04225c

Abstract

The anaerobic ammonium oxidation (anammox) process has gained much popularity in recent years following its success in nitrogen removal. However, not much has been reported on techniques to promote anammox bacteria immobilization and associated microbial community evolution. In this study, a novel upflow porous-plate anaerobic reactor (UPPAR) was developed and explored to promote biomass (anammox) retention and growth. To comprehend the performance of the UPPAR, its nitrogen removal efficiencies, as well as the microbial community dynamics involved in the nitrogen removal process, was evaluated and reported. When NLR ranging 0.98–1.08 kg m−3 d−1 was introduced at various stages of the UPPAR operation, a rapid start-up was achieved in 63 d, and the overall nitrogen removal rate could reach 90–95%. By the end of the start-up period, it was revealed that Proteobacteria abundance had reduced by 43.92% as opposed Planctomycetes which increased from 2.95% to 43.52%. Conversely, after the UPPAR had been operated for 124 d, thus at steady-state, the most pronounced phylum observed was Planctomycetes (43.52%) followed by Proteobacteria (26.63%), Chloroflexi (5.87%), Ignavibacteriae (5.55%), and Bacteroidetes (4.9%). Predominant genera observed included Candidatus Kuenenia – (25.46%) and Candidatus Brocadia – (3.15%), an indication that nitrogen removal mechanism within the UPPAR was mainly conducted via autotrophic anammox process. Scanning electron microscopy (SEM) revealed that sludge samples obtained at steady-state were predominantly in granular form with sizes ranging between 2 mm to 5 mm. Granules surfaces were dominated with normal to coccoid-shaped cells as revealed by the SEM.

Highlights

The concept of industrialization has gained extensive attention in recent years following its signi cant contribution in a country's development and improvement of economies or the lives of people
As Nitrogen loading rate (NLR) of 0.27 kg mÀ3 dÀ1 was employed in the upflow porous-plate anaerobic reactor (UPPAR) in stage-I, it was found that effluent NH4+-N concentration was relatively higher compared to that in the in uent (Fig. 2B)
Over 90% of nitrogen removal was achieved when NLR of 1.08 kg mÀ3 dÀ1 was employed in the UPPAR at the steady-state

Summary

Introduction

The concept of industrialization has gained extensive attention in recent years following its signi cant contribution in a country's development and improvement of economies or the lives of people. Industrialization and its related activities have always affected many key natural resources including environment, water bodies, land, and air. Industrial activities generate huge volumes of wastewater containing signi cant concentrations of nitrogen, carbon, and phosphorus. Wastewater characterized by these pollutants and nutrients o en leads to water eutrophication and impact negatively on both human and aquatic life. Wastewater (industrial, domestic or municipal) treatment is no doubt, an important agenda that requires extensive promotion to avoid environmental pollution and its related consequences. Government-mandated institutions are enforcing pollution laws, a more stringent discharge standard is paramount to achieving a healthy water life across the globe.[1]

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Results

Conclusion