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Updated: Jun 24, 2025
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Partial nitrification and simultaneous denitrification in sequential anaerobic and aerobic reactors: performance and
Marcus V A Santos1, Juliana C Morais2, Shyrlane T S Veras1
1Department of Civil and Environmental Engineering, Laboratory of Environmental Sanitation, Federal University of Pernambuco, Recife, Brazil.
This study evaluated a two-reactor system for domestic sewage treatment, achieving high removal of chemical oxygen demand (COD) and total nitrogen (TN) through simultaneous nitrification and denitrification (SND). The system demonstrated efficient organic matter and nitrogen removal, with optimized conditions yielding excellent effluent quality.
Area of Science:
- Environmental Engineering
- Wastewater Treatment
- Microbial Ecology
Background:
- Domestic sewage contains significant organic matter and nitrogen, requiring effective removal to prevent environmental pollution.
- Conventional wastewater treatment methods often involve multiple stages and can be energy-intensive.
- Simultaneous Nitrification and Denitrification (SND) offers a promising approach for efficient nitrogen removal in a single reactor or system.
Purpose of the Study:
- To evaluate the efficiency of a two-sequential-reactor system (anaerobic-aerobic) for removing organic matter and nitrogen from domestic sewage.
- To investigate the impact of low dissolved oxygen (DO) concentrations and effluent recirculation on the simultaneous nitrification and denitrification (SND) process.
- To characterize the microbial community dynamics associated with the observed treatment performance.
Main Methods:
- A two-stage system comprising an anaerobic reactor (ANR) and an aerobic reactor (AER) with polyurethane foam support was employed.
- The AER was operated at varying low dissolved oxygen (DO) concentrations (3.0 and 1.5 mg/L) across three operational phases.
- Effluent recirculation from AER to ANR was implemented in the final phase (PIII); microbial community analysis was conducted using massive sequencing.
Main Results:
- The system achieved high removal efficiencies, with Chemical Oxygen Demand (COD) removal reaching approximately 94% and Total Nitrogen (TN) removal reaching approximately 65% in Phase III.
- Effluent concentrations were reduced to below 30 mg COD/L and 15 mg TN-N/L under optimized conditions.
- Kinetic assays revealed significant nitrification and denitrification rates, with dominant microbial communities including *Rhodococcus*, *Nitrosomonas*, *Pseudomonas*, and *Porphyromonas*, supporting the SND process.
Conclusions:
- The sequential anaerobic-aerobic reactor system, particularly under low DO conditions with effluent recirculation, is highly effective for domestic sewage treatment.
- The study confirmed the feasibility and efficiency of the simultaneous nitrification and denitrification (SND) process in the aerobic reactor.
- Microbial community analysis provided insights into the biological mechanisms driving the efficient removal of organic matter and nitrogen.
