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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
A free nitrous acid (FNA)-based technology for reducing sludge production
Qilin Wang1, Liu Ye, Guangming Jiang
1Advanced Water Management Centre (AWMC), The University of Queensland, QLD 4072, Australia. wangqilin666@hotmail.com
Water Research
|June 4, 2013
Summary
Free nitrous acid (FNA) treatment significantly reduces sludge production in wastewater plants by 28%. FNA-treated sludge also supports wastewater treatment and can be used for denitrification.
Area of Science:
- Environmental Engineering
- Wastewater Treatment Technologies
- Microbial Ecology
Background:
- Sludge management is a major operational challenge in wastewater treatment plants, accounting for up to 60% of costs.
- Effective sludge reduction strategies are crucial for improving the economic and environmental sustainability of these facilities.
Purpose of the Study:
- To investigate the efficacy of free nitrous acid (FNA) treatment for reducing excess sludge production in biological wastewater treatment.
- To evaluate the impact of FNA treatment on sludge properties and overall wastewater treatment performance.
Main Methods:
- Two sequencing batch reactors (SBRs) were operated: one control and one experimental.
- The experimental reactor involved treating 50% of excess sludge with FNA (2.0 mg N/L for 24-42 h) before returning it to the parent reactor.
- Sludge wastage was adjusted to maintain similar mixed liquor suspended solids (MLSS) concentrations in both reactors.
Main Results:
- Sludge production in the FNA-treated system was 28% lower compared to the control.
- FNA treatment did not adversely affect organic carbon and nitrogen removal efficiency.
- Key sludge properties, including settleability and nitrous oxide (N2O) emissions, remained unaffected by FNA treatment.
Conclusions:
- Free nitrous acid (FNA) offers a promising strategy for significant sludge reduction in wastewater treatment.
- FNA-treated sludge can be effectively reintroduced into the treatment process without compromising effluent quality or sludge characteristics.
- FNA-treated sludge demonstrates potential as a carbon source for endogenous denitrification, offering further process benefits.
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