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Updated: Jun 12, 2026
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Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Nitrogen removal from reject water with primary sludge as denitrification carbon source
1School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang Province, China. zhangliang_1986@126.com
Summary
A novel system effectively removes nitrogen from reject water using simultaneous sludge fermentation and denitrification. This process achieves over 90% total nitrogen removal efficiency without external carbon sources.
Area of Science:
- Environmental Engineering
- Wastewater Treatment
- Microbial Ecology
Background:
- Reject water poses challenges for nitrogen removal due to high ammonia concentrations.
- Conventional denitrification requires supplemental carbon sources, increasing operational costs.
- Simultaneous sludge fermentation and denitrification offer a potential solution for in-situ carbon generation.
Purpose of the Study:
- To develop and evaluate a novel system for nitrogen removal from reject water.
- To investigate the efficacy of using primary sludge as an intermittent electron donor for denitrification.
- To assess the impact of effluent recycle and operational parameters on nitrogen removal efficiency.
Main Methods:
- Implementation of a coupled anoxic/oxic reactor for nitrification and a specialized denitrification reactor.
- Intermittent addition of primary sludge as an electron donor in the denitrification reactor.
- Monitoring of key parameters including total nitrogen, volatile suspended solids, alkalinity, and oxidation-reduction potential (ORP).
Main Results:
- Achieved over 90% total nitrogen removal efficiency without external carbon addition.
- Demonstrated simultaneous sludge fermentation and denitrification, promoting both processes.
- Observed a 50% reduction in volatile suspended solids due to primary sludge degradation.
- Identified effluent recycle as beneficial for alkalinity recovery and nitrogen removal.
Conclusions:
- The novel system effectively removes nitrogen from reject water using primary sludge as an in-situ carbon source.
- Simultaneous sludge fermentation and denitrification is a viable and efficient wastewater treatment strategy.
- Oxidation-reduction potential (ORP) can serve as a reliable control parameter for primary sludge addition.
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