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Towards mainstream anammox: lessons learned from pilot-scale research at WWTP Dokhaven
Maaike Hoekstra1, Stefan P Geilvoet2, Tim L G Hendrickx3
1a Department of Biotechnology, Faculty of Applied Sciences , Delft University of Technology , Delft , Netherlands.
Environmental Technology
|April 27, 2018
Summary
Partial Nitritation/Anammox (PN/A) technology effectively removes nitrogen from wastewater, even at lower winter temperatures. This biological process shows feasibility for municipal wastewater treatment by suppressing competing bacteria.
Area of Science:
- Environmental biotechnology
- Wastewater treatment engineering
- Microbial ecology
Background:
- Nitrogen removal from municipal wastewater is crucial for environmental protection.
- Partial Nitritation/Anammox (PN/A) is a promising biological nitrogen removal technology.
- Understanding PN/A feasibility across temperature variations is essential for practical application.
Purpose of the Study:
- To assess the biological feasibility of PN/A technology for municipal mainstream wastewater.
- To quantify nitrogen removal rates at different temperature conditions (summer and winter).
- To investigate the suppression of nitrite-oxidizing bacteria (NOB) within the PN/A process.
Main Methods:
- Stable operation of PN/A reactors under controlled temperature conditions.
- Measurement of total nitrogen removal rates.
- Activity tests to assess microbial populations (NOB, ammonia-oxidizing bacteria, anammox bacteria).
- Monitoring of dissolved oxygen concentration.
Main Results:
- Significant nitrogen removal rates were observed: 0.223 ± 0.029 kg N/(m³·d) at 23.2°C and 0.097 ± 0.016 kg N/(m³·d) at 13.4°C.
- Successful suppression of NOB activity was achieved across the studied temperature range.
- Ample capacity of ammonia-oxidizing bacteria and anammox bacteria was consistently maintained.
- Low dissolved oxygen levels were key to suppressing NOB activity.
Conclusions:
- PN/A technology is biologically feasible for nitrogen removal from municipal mainstream wastewater.
- The process demonstrates effectiveness across a range of temperatures relevant to municipal wastewater.
- Maintaining low dissolved oxygen is critical for successful PN/A operation and NOB suppression.
- Future research should focus on the long-term stability of PN/A, particularly the preceding biological oxygen demand removal step.
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