Pilot-scale study of a structured bed reactor for nitrogen and organic matter removal from sanitary sewage: advances and design challenges

Kiemi De Brito Murata,Eugenio Foresti,Rafael Brito De Moura,Dagoberto Yukio Okada,Bruno Garcia Silva,Carla Eloísa Diniz Dos Santos,Márcia Helena Rissato Zamariolli Damianovic

doi:10.33448/rsd-v10i13.21560

Abstract

Simultaneous nitrification and denitrification (SND) is a process that can remove both nitrogen and organic matter in a single unit. Several bench-scale studies show that the structured bed reactors (STBR) subjected to recirculation and intermittent aeration have achieved a good performance for SND treating different types of wastewater. Thus, this study took a step forward and evaluated the efficiency and stability of treating domestic sewage in a pilot-scale STBR. COD removal efficiencies higher than 87% were achieved in the whole experimental period. The highest Total-N removal efficiency was approximately 74 ± 7% by adopting a hydraulic retention time (HRT) of 47.2 h and intermittent aeration (2 h aerated and 1 h non-aerated). The setup of the aeration system was an important mechanism to ensure the optimal balance between nitrification and denitrification in a pilot-scale system.

Highlights

Basic sanitation universalization poses as a challenge in developing countries such as Brazil
According to the SNIS (Brazilian Sanitation Information System), in 2018, 60.9% of the urban domestic sewage produced in Brazil was collected and only 46.3% of the generated sewage received some type of treatment (Sistema Nacional de Informações sobre Saneamento, 2019)
The highest Total-N removal efficiency was achieved in Stage 4 and a low nitrification rate was observed at Stage 3

Summary

Introduction

Basic sanitation universalization poses as a challenge in developing countries such as Brazil. In Brazilian isolated communities and rural areas, access to basic sanitation infrastructure is almost non-existent. In these areas, the options adopted are decentralized systems which comprise the collection, treatment, and disposal or reuse of wastewater from individual houses, clusters, rural communities, isolated commercial, industrial, and agricultural facilities or places located near the waste generation (Gikas & Tchobanoglous, 2009). The decision-making should consider that few will pay the costs of implementing/maintaining such decentralized treatment systems. These units demand simplicity in the construction, operation, and waste management to become feasible. The common options for sewage management adopted are improperly constructed cesspits and final disposal in water bodies and/or soil (IBGE, 2015)

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