The anaerobic ammonium oxidation (anammox) process is well-known as a low-energy consuming and eco-friendly technology for treating nitrogen-rich wastewater. Although the anammox reaction was widely investigated in terms of its application in many wastewater treatment processes, practical anammox application at the pilot and industrial scales is limited because nitrogen removal efficiency and anammox activity are dependent on many operational factors such as temperature, pH, dissolved oxygen concentration, nitrogen loading, and organic matter content. In practical application, anammox bacteria are possibly vulnerable to non-essential compounds such as sulfides, toxic metal elements, alcohols, phenols, and antibiotics that are potential inhibitors owing to the complexity of the wastewater stream. This review systematically summarizes up-to-date studies on the effect of various operational factors on nitrogen removal performance along with reactor type, mode of operation (batch or continuous), and cultured anammox bacterial species. The effect of potential anammox inhibition factors such as high nitrite concentration, high salinity, sulfides, toxic metal elements, and toxic organic compounds is listed with a thorough interpretation of the synergistic and antagonistic toxicity of these inhibitors. Finally, the strategy for optimization of anammox processes for wastewater treatment is suggested, and the importance of future studies on anammox applications is indicated.

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Performance of Anammox Processes for Wastewater Treatment: A Critical Review on Effects of Operational Conditions and Environmental Stresses

Evaluation of the inhibitory effects of heavy metals on anammox activity: A batch test study.

Enhancement of anammox performance by Cu(II), Ni(II) and Fe(III) supplementation.

BACKGROUND

Anaerobic ammonium oxidation (anammox) is a promising approach for removing nitrogen from landfill leachates and other nitrogen-laden wastewater. Although heavy metals, which are known for their microbial toxicity, are commonly present in those wastewater streams information on their inhibitory impact on anammox activity is still limited. The main aim of this study is to investigate the inhibitory effects of six common metal ions (Cu2+, Cd2+, Ni2+, Zn2+, Pb2+, and molybdate) on anammox activity.



RESULTS

The soluble concentrations of cationic metals decreased due to precipitation reactions. Cu, Zn, Cd, and Ni were the most toxic metals with 50% inhibiting soluble concentrations of 4.2, 7.6, 11.2, and 48.6 mg L-1, respectively. Molybdate and Pb2+ were not or only moderately inhibitory at the highest soluble concentrations tested (22.7 mg Mo L-1 and 6.0 mg Pb L-1, respectively). A noncompetitive inhibition model successfully described the relationship between microbial inhibition and metal concentrations for all tested metals except for Pb.



CONCLUSION

Cu, Zn and Cd were the most toxic heavy metals for anammox bacteria. The soluble concentration of these heavy metals needs to be monitored carefully before applying anammox processes. © 2014 Society of Chemical Industry

Inhibition of anaerobic ammonium oxidation by heavy metals

https://ir.nctu.edu.tw:443/bitstream/11536/24861/1/000338710700017.pdf

Effect of zinc on anammox activity and performance of simultaneous partial nitrification, anammox and denitrification (SNAD) process

The effect of Cu(II) stress on the activity, performance and recovery on the Anaerobic Ammonium-Oxidizing (Anammox) process

Estimating the recovery of ANAMMOX performance from inhibition by copper (II) and oxytetracycline (OTC)

The invention relates to a high-efficiency anaerobic ammonia oxidation reactor. The reactor comprises a reaction container, a main water inlet and a main water outlet, wherein a plurality of clapboards are arranged in the reaction container and divide the reaction container into a plurality of independent reaction chambers in turn; the frontmost independent reaction chamber is communicated with the main water inlet; the rearmost independent reaction chamber is communicated with the main water outlet; each clapboard is provided with a channel; a combined baffle plate for dividing each independent reaction chamber into a downward flow area and an upward flow area is arranged in each independent reaction chamber; the downward flow area is close to the main water inlet; the upward flow area is close to the main water outlet; the combined baffle plate comprises a vertical part for dividing each independent reaction chamber and a chamfer part for allowing a substrate to flow into the upward flow area from the downward flow area; and an independent substrate water inlet is formed at the bottom of each independent reaction chamber. The reactor has the advantages that: starting time is short, the stability of the reactor is enhanced, the inhibitory influence of high substrate concentration inlet water on anaerobic ammonia oxidation bacteria is reduced, and the whole process load is improved while process stability is kept.

High-efficiency anaerobic ammonia oxidation reactor

A high-efficiency anaerobic ammonium oxidation reactor comprises a reaction vessel, a main water inlet and a main water outlet. A plurality of partition plates are arranged in the reaction vessel and used for sequentially dividing the reaction vessel into a plurality of independent reaction chambers; the first independent reaction chamber is communicated with the main water inlet; the last independent reaction chamber is communicated with the main water outlet; a channel is arranged on each partition plate; a combined baffle plate for dividing each independent reaction chamber into a down-flow area and an up-flow area is arranged in each independent reaction chamber; each down-flow area is closed to the main water inlet; each up-flow area is close to the main water outlet; each combined baffle plate comprises a vertical portion for dividing the corresponding independent reaction chamber and a chamfer portion allowing matrix to flow from each down-flow area into the corresponding up-flow area; and an independent matrix water inlet is arranged at the bottom of each independent reaction chamber. The high-efficiency anaerobic ammonium oxidation reactor has the advantages of short starting time, strengthened stability, reduction of the influence of inlet water with high matrix concentration on anaerobic ammonium oxidation bacteria, retention of technical stability and improvement of integral technical load.

Hui Wang

Papers

The effect of Cu(II) stress on the activity, performance and recovery on the Anaerobic Ammonium-Oxidizing (Anammox) process

Estimating the recovery of ANAMMOX performance from inhibition by copper (II) and oxytetracycline (OTC)

High-efficiency anaerobic ammonia oxidation reactor

High-efficiency anaerobic ammonium oxidation reactor