Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; Department of Geography and Resource Management, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong Special Administrative Region.
Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China; College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China.
Water Res. 2024 May 1;254:121387. doi: 10.1016/j.watres.2024.121387. Epub 2024 Feb 27.
Constructed wetlands (CWs) are frequently used for effective biological treatment of nitrogen-rich wastewater with external carbon source addition; however, these approaches often neglect the interaction between plant litter and biochar in biochar-amended CW environments. To address this, we conducted a comprehensive study to assess the impacts of single or combined addition of common reed litter and reed biochar (pyrolyzed at 300 and 500 °C) on nitrogen removal, greenhouse gas emission, dissolved organic matter (DOM) dynamics, and microbial activity. The results showed that combined addition of reed litter and biochar to CWs significantly improved nitrate and total nitrogen removal compared with biochar addition alone. Compared to those without reed litter addition, CWs with reed litter addition had more low-molecular-weight and less aromatic DOM and more protein-like fluorescent DOM, which favored the enrichment of bacteria associated with denitrification. The improved nitrogen removal could be attributed to increases in denitrifying microbes and the relative abundance of functional denitrification genes with litter addition. Moreover, the combined addition of reed litter and 300 °C-heated biochar significantly decreased nitrous oxide (30.7 %) and methane (43.9 %) compared to reed litter addition alone, while the combined addition of reed litter and 500 °C-heated biochar did not. This study demonstrated that the presences of reed litter and biochar in CWs could achieve both high microbial nitrogen removal and relatively low greenhouse gas emissions.
人工湿地（CWs）常用于添加外部碳源以有效处理富氮废水，但这些方法往往忽略了生物炭添加的 CW 环境中植物凋落物和生物炭之间的相互作用。为了解决这个问题，我们进行了一项综合研究，评估了单独或联合添加普通芦苇凋落物和芦苇生物炭（在 300 和 500°C 下热解）对氮去除、温室气体排放、溶解有机物（DOM）动态和微生物活性的影响。结果表明，与单独添加生物炭相比，CWs 中同时添加芦苇凋落物和生物炭可显著提高硝酸盐和总氮去除率。与未添加芦苇凋落物的 CWs 相比，添加芦苇凋落物的 CWs 具有更多的低分子量和更少的芳香 DOM，以及更多的蛋白样荧光 DOM，这有利于与反硝化相关的细菌的富集。添加芦苇凋落物可提高氮去除率，这归因于添加凋落物后反硝化微生物和功能反硝化基因的相对丰度增加。此外，与单独添加芦苇凋落物相比，联合添加芦苇凋落物和 300°C 热解生物炭可显著降低氧化亚氮（30.7%）和甲烷（43.9%）的排放量，而联合添加芦苇凋落物和 500°C 热解生物炭则没有。本研究表明，CWs 中存在芦苇凋落物和生物炭可以实现高微生物氮去除和相对低的温室气体排放。
