Recent Published Articles

Feasibility of low-intensity ultrasound treatment with hydroxylamine to accelerate the initiation of partial nitrification and allow operation under intermittent aeration

Shuiyu Sun , Jianxiong Jian , Xiaojian Liao , Zhihua Mo , Shoupeng Li , Lei Li , Shaojin Chen , Zhenhua Huang , Junhao Chen , Wencan Dai


Received March 24, 2023,Revised , Accepted June 04, 2023, Available online June 10, 2023

Volume 36,2024,Pages 446-459

Partial nitrification is a key aspect of efficient nitrogen removal, although practically it suffers from long start-up cycles and unstable long-term operational performance. To address these drawbacks, this study investigated the effect of low intensity ultrasound treatment combined with hydroxylamine (NH2OH) on the performance of partial nitrification. Results show that compared with the control group, low-intensity ultrasound treatment (0.10 W/mL, 15 min) combined with NH2OH (5 mg/L) reduced the time required for partial nitrification initiation by 6 days, increasing the nitrite accumulation rate (NAR) and ammonia nitrogen removal rate (NRR) by 20.4% and 6.7%, respectively, achieving 96.48% NRR. Mechanistic analysis showed that NH2OH enhanced ammonia oxidation, inhibited nitrite-oxidizing bacteria (NOB) activity and shortened the time required for partial nitrification initiation. Furthermore, ultrasonication combined with NH2OH dosing stimulated EPS (extracellular polymeric substances) secretion, increased carbonyl, hydroxyl and amine functional group abundances and enhanced mass transfer. In addition, 16S rRNA gene sequencing results showed that ultrasonication-sensitive Nitrospira disappeared from the ultrasound + NH2OH system, while Nitrosomonas gradually became the dominant group. Collectively, the results of this study provide valuable insight into the enhancement of partial nitrification start-up during the process of wastewater nitrogen removal.

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