摘要
孔隙水是沉积物和上覆水之间物质交换的重要媒介,污染物可以通过孔隙水对流、扩散等方式向上覆水中迁移,加剧上覆水体的污染。采用自制电动导排孔隙水装置,设置5组对照实验,模拟了导排沉积物孔隙水对氮磷污染沉积物的修复,分析了泥–水界面氮磷释放通量,探讨了不同实验条件对沉积物内源释放与微生物多样性的影响。结果表明:导排孔隙水可以显著抑制泥–水界面氮磷释放,但是氮磷的响应存在差异。通电导排孔隙水后泥–水界面总氮(TN)释放通量总体呈逐步下降趋势,变化范围为–15.698~79.903 mg/(m^(2)·d),实验进行14 d即可使TN释放通量降低为最大释放通量的10%以内。与对照组相比,仅导排孔隙水可以使泥–水界面氮释放通量减低76.72%,通电后界面释放通量最终降幅可达95.53%以上。泥–水界面总磷(TP)释放通量在实验进行28 d内呈波动变化,其范围为–3.558~4.279 mg/(m^(2)·d),当实验时间超过70 d以后,除对照组以外,泥–水界面磷释放通量均为负值,最终沉积物从磷的“源”转为“汇”。实验结束后,沉积物中pH值、有机质含量(LOI)没有发生显著变化。导排孔隙水后沉积物中TP降低约1.06%~5.02%。TN含量减少主要发生在阳极,相对于初始状态减少了2.65%~13.63%。电动导排孔隙水对沉积物中微生物α多样性影响较小,在电场作用下沉积物中微生物的Chao1指数、ACE指数略有降低,但在统计学上无显著差异。沉积物中微生物群落组成相似,在门水平上,均以变形菌门(13.41%~24.40%)、拟杆菌门(12.77%~29.71%)和绿弯菌门(5.01%~18.64%)为主。冗余分析表明,对微生物群落结构影响较大的因素为沉积物pH值、含水率,其次为沉积物LOI和电导率,沉积物中总磷含量的影响最小。研究表明,通过电动导排孔隙水修复氮磷污染沉积物是一种具有应用前景的技术选择。
Pore water plays a key role in sediment nutrient exchange.This study uses electrokinetic geosynthetics(EKGs)as electrodes to drain sediment pore water in the presence of overlying water and conducts five sets of indoor experiments(one control group and four groups exposed to voltage gradients of 0,0.5(intermittent power),0.5(continuous power),and 1.0 V/cm(intermittent power))to investigate the performance and mechanisms of pore water drainage in regulating sediment nutrient release and the response of microbial communities.The results showed that draining pore water significantly inhibits the release of nitrogen and phosphorus at the sediment-water interface(SWI).However,the responses of nitrogen and phosphorus exhibit differences.The TN release flux at the SWI shows a gradual downward trend,ranging from–15.698 to 79.903 mg/(m^(2)·d).Within 14 days of the experiment,the TN release flux reduces to within 10%of the maximum release flux.Compared to the control,conducting pore water drainage alone reduces the nitrogen release flux at the SWI by 76.72%.In contrast,the TP release flux at the SWI fluctuates within the 28-day experiment,ranging from–3.558 to 4.279 mg/(m^(2)·d).After the experiment,the pH and LOI of the sediment do not change significantly.TP decreases by approximately 1.06%~5.02%following drainage,while the reduction in TN content occurs primarily near the anode,decreasing by 2.65%~13.63%compared to the initial state.The drainage causes a nonsignificant decline in community abundance indices(the Chao1 index and ACE index of microorganisms in the sediment are slightly reduced)but does not change the dominant species of sediment microorganisms.The dominant phyla are Proteobacteria(13.41%~24.40%),Bacteroides(12.77%~29.71%),and Chloroflexi(5.01%~18.64%).The pH and water content are the primary factors affecting microbial community structure,while the LOI and conductivity of the sediment are secondary factors.The total phosphorus content in the sediment has the least impact.The research demonstrates that the electric drainage of pore water is an economical and low-ecological-impact technology for restricting in-situ sediment nutrient release.
作者
黎睿
汤显强
胡艳平
卢士强
顾鋆鋆
孙远军
LI Rui;TANG Xianqiang;HU Yanping;LU Shiqiang;GU Junjun;SUN Yuanjun(Basin Water Environmental Department,Changjiang River Scientific Research Institute,Wuhan 430010,China;Shanghai Engineering Research Center of Water Environment Simulation and Ecological Restoration,Shanghai Academy of Environment Sciences,Shanghai 200233,China;Key Laboratory of Basin Water Resource and Eco-Environmental Science in Hubei Province,Wuhan 430010,China)
出处
《工程科学与技术》
北大核心
2025年第1期234-243,共10页
Advanced Engineering Sciences
基金
湖北省自然科学基金重点项目(2024AFD349)
国家自然科学基金面上项目(51979006)
中央级公益性科研院所基本科研业务项目(CKSF2021444/SH,CKSF2023188/SH)
上海水环境模拟与水生态修复工程技术研究中心资助项目(WESER-202204)。
关键词
孔隙水
沉积物
电动修复
释放通量
微生物多样性
pore water
sediment
electrokinetic remediation
release flux
microbial biodiversity
作者简介
黎睿(1990-),男,高级工程师,硕士.研究方向:富营养化水体治理技术研发.E-mail:Leeruiwh@outlook.com;通信作者:汤显强,正高级工程师,E-mail:ckyshj@126.com;通信作者:卢士强,正高级工程师,E-mail:Lusq@saes.sh.cn。
