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Nutrient removal through pyrrhotite autotrophic denitrification: Implications for eutrophication control.
Yongwei Zhang1, Dongyang Wei2, Liam Morrison3
1State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, 163# Xianlin Avenue, Nanjing 210023, China.
The Science of the Total Environment
|January 29, 2019
Summary
This study shows natural pyrrhotite autotrophic denitrification (PAD) effectively removes nitrate and phosphate from wastewater. PAD biofilters utilize specific bacteria, Thiobacillus and Sulfurimonas, for simultaneous biological nitrogen and chemical phosphorus removal.
Area of Science:
- Environmental Science
- Environmental Engineering
- Microbiology
Background:
- Wastewater treatment faces challenges in simultaneously removing nitrogen and phosphorus.
- Autotrophic denitrification using natural pyrrhotite offers a potential solution for nutrient removal.
- Understanding the kinetics and microbial community is crucial for optimizing PAD processes.
Purpose of the Study:
- To investigate the nutrient removal kinetics and influencing factors of natural pyrrhotite autotrophic denitrification (PAD).
- To evaluate the nutrient removal performance and microbial community dynamics in a PAD biofilter (PADB).
- To assess the efficacy of PAD technology for controlling eutrophication.
Main Methods:
- Experimental investigation of nutrient removal kinetics under varying conditions.
- Operation of a PAD biofilter (PADB) to assess performance.
- Analysis of microbial community composition using molecular techniques.
- Kinetic modeling of nitrate removal.
Main Results:
- PAD achieved near-complete removal of nitrate (NO3-) and phosphate (PO43-).
- Nitrate removal followed half-order kinetics and was effective across a wide range of temperatures and initial nutrient concentrations.
- The PAD biofilter demonstrated efficient nutrient removal, reducing nitrate-N to 1.15 mg·L-1 and phosphate-P to 0.09 mg·L-1 at 12h HRT.
- Thiobacillus and Sulfurimonas were identified as dominant bacteria, utilizing pyrrhotite as an electron donor for nitrate reduction, with their abundance varying spatially within the biofilter.
Conclusions:
- Natural pyrrhotite autotrophic denitrification is a highly effective method for simultaneous biological nitrogen and chemical phosphorus removal from wastewater.
- PAD technology demonstrates robustness across a range of operating conditions, making it suitable for practical applications.
- The microbial community, particularly Thiobacillus and Sulfurimonas, plays a critical role in the PAD process.
- PAD-based technologies present a promising strategy for mitigating eutrophication in water bodies.
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