School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Sci Total Environ. 2022 Nov 20;848:157708. doi: 10.1016/j.scitotenv.2022.157708. Epub 2022 Jul 29.
To further explore the response mechanism of microorganisms to the synchronous control of nitrogen and phosphorus release from sediments by CaO, the spatiotemporal changes in the physical, chemical and biological indicators of the overlying water, interstitial water and sediments in each reactor were measured in the experiment. The experiment results showed that CaO could increase the ammonia monooxygenase activity, nitrite oxidase activity and Nitrospira abundance in the sediment near its dosing position, and enhanced the activities of nitrate reductase and nitrite reductase at a certain distance from the dosing position, thereby promoting nitrogen removal in sediments through the alternating process of nitrification and denitrification. At the same time, the increase of alkaline phosphatase activity and Saccharimonadales abundance in the test groups accelerated the hydrolysis of organic phosphorus, and the P immobilization in sediments was realized through the subsequent precipitation reaction of Ca and PO under alkaline conditions. In addition, the enhanced activities of dehydrogenase and catalase ensured that CaO would not cause great killing effect on microorganisms when improving the hypoxic conditions and inhibiting endogenous release. As a result, the dissolved product of CaO such as Ca(OH) and HO reduced the nutrients concentration and killed the algae, which kept the algae density and chlorophyll a concentration at a low level throughout the test groups. Therefore, this study systematically clarified the microbial mechanism of CaO synchronously controlling the release of nitrogen and phosphorus from sediments, which provided a new idea for the remediation of endogenous pollution in the water system.
为了进一步探索 CaO 对沉积物中氮磷同步释放的微生物响应机制，本实验测量了每个反应器中上层水、间隙水和沉积物的物理、化学和生物指标的时空变化。实验结果表明，CaO 可以增加投加点附近沉积物中的氨单加氧酶活性、亚硝酸盐氧化酶活性和 Nitrospira 丰度，并增强投加点一定距离处硝酸盐还原酶和亚硝酸盐还原酶的活性，从而通过硝化和反硝化的交替过程促进沉积物中的氮去除。同时，碱性磷酸酶活性和 Saccharimonadales 丰度的增加加速了有机磷的水解，在碱性条件下，Ca 和 PO 的后续沉淀反应实现了沉积物中磷的固定。此外，增强的脱氢酶和过氧化氢酶活性确保了 CaO 在改善缺氧条件和抑制内源性释放时不会对微生物产生巨大的杀伤作用。结果，CaO 的溶解产物如 Ca(OH) 和 HO 降低了营养物浓度并杀死了藻类，使藻类密度和叶绿素 a 浓度在整个实验组中保持在较低水平。因此，本研究系统地阐明了 CaO 同步控制沉积物中氮磷释放的微生物机制，为水体内源污染的修复提供了新的思路。
