| 论文摘要： |
The low oxygen environment significantly affects the effectiveness of passivating agent control technology. This study examined the combined effects of ultra-nano oxygenation (UNO) and composite nutrients control agents (CNCA) on carbon (C), nitrogen (N), and phosphorus (P) management in sediments. The integration of these technologies shifted ammonium and P from a release to an adsorption state, evidenced by low equilibrium P concentration (EPC0) by 65.9 %-69.0 %, attributed to increased iron and manganese from CNCA and enhanced dissolved oxygen (DO) by 40 %-49 % from UNO. Subsequently, the combined application of UNO and CNCA led to nitrite (NO2--N) accumulation (up:15 % similar to 26 %), potentially triggering classical denitrification, short-cut denitrification, and anammox processes. Additionally, glucosidase activity increased, leading to a 40 %-42 % rise in dissolved organic C, providing sufficient electron donors for denitrification. Meanwhile, coupled with the accumulation of iron-manganese bound P, the core microbial communities were induced with the dominant denitrifying P-accumulating organisms (DPAOs) Dechloromonas (up:0.26-1.25 fold). All these factors contributed to the high N removal efficiency evidenced by higher denitrification rate, key genes and genera. In summary, based on the coupling mechanism of C, N and P, the combination of UNO and CNCA demonstrated significant advantages and potential for P stabilization and N removal by regulating adsorption-desorption state, redox state, electron donors, key microbial community composition and abundance. The technologies overcome the limitations of traditional passivation methods in anoxic environments by enhancing oxygen levels to strengthen the remediation effect, providing a more optimized solution for water body management. |
