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| 东南丘陵山区深水水库两种浮床植物脱氮效率对比研究 |
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倪子怡1, 许海1, 詹旭2, 孙起亮3, 朱广伟1, 程新良4, 王裕成4, 朱梦圆1, 邹伟1
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1.中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室;2.江南大学环境与土木工程学院;3.杭州市桐庐县环境保护监测站;4.杭州市生态环境局淳安分局
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| 摘要: |
| 为探究东南丘陵山区深水水库中生态浮床技术深度脱氮的效率及管理措施，以大型山谷型深水水库千岛湖为例，选取湿生植物空心菜（Ipomoea aquatica）和水生植物粉绿狐尾藻（Myriophyllum aquaticum），采用生态浮床技术，通过原位模拟试验对比研究，探究了不同营养盐浓度和光强下2种植物的生长状况与氮素去除效率。结果发现：（1）空心菜长势受营养盐和光照条件影响明显，添加氮磷后（TN = 2.37 mg/L，TP = 0.046 mg/L）的空心菜生物量是原位水体（TN = 0.66 mg/L，TP = 0.028 mg/L）的1.6倍，适当遮光有助于浮床植物生长，40%遮光条件下空心菜的生物量是不遮光条件下的1.5倍；而粉绿狐尾藻生长受营养盐和光照条件影响均较小。（2）空心菜对于水体氮素净化能力显著高于粉绿狐尾藻，在最佳条件下空心菜和粉绿狐尾藻对氮素的去除效率分别可达213.30 mg/(m2·d)和44.23 mg/(m2·d)。（3）空心菜氮去除主要以植物同化作用为主，占70%以上的TN去除量，40%遮光的环境通过明显提升空心菜同化吸收氮量和根系反硝化速率以增强氮的去除；粉绿狐尾藻同化吸收和反硝化脱氮作用各占50%左右。本研究表明，采用生态浮床技术能够强化深水水库的脱氮能力，空心菜更适合在氮浓度较高的水体生长，夏季为空心菜和粉绿狐尾藻浮床分别进行40%和75%的遮光处理将有更好的水质净化效果。因此，在滨岸湿地匮乏的深水水库实施多种植物搭配的生态浮床技术强化水体脱氮作用是一种行之有效的水质改善方法。 |
| 关键词: 生态浮床 反硝化 千岛湖 光照 营养盐浓度 |
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| 基金项目:国家自然科学基金项目（42271126）、江苏省科技厅项目（BK20220041）、中国科学院南京地理与湖泊研究所自主部署科研项目（NIGLAS2022GS03）、杭州市生态环境局淳安分局委托项目（ZJCZZF[2021]17号） |
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| Comparative research on nitrogen removal efficiency of two floating bed plants in deep reservoir of southeastern hilly mountain region |
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NI Ziyi1, XU Hai1, ZHAN Xu2, Sun Qiliang3, ZHU Guangwei1, CHENG Xinliang4, WANG Yucheng4, ZHU Mengyuan1, ZOU Wei1
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1.State Key Laboratory of Lakes and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences;2.School of Environment and Civil Engineering,Jiangnan University;3.Tonglu Environmental Protection Monitoring Station of Hangzhou;4.Hangzhou Bureau of Ecology and Environment Chun′an Branch
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| Abstract: |
| To investigate the efficiency and management measures of deep nitrogen removal by ecological floating bed technology in deep-water reservoir of southeast hilly region, hygrophytes (Ipomoea aquatica) and aquatic plants (Myriophyllum aquaticum) were selected as examples in Qiandao Lake, a large valley-type deep-water reservoir. Their growth and nitrogen removal efficiency under different nutrient concentrations and light intensities were studied through in-situ simulation experiments using the ecological floating bed technique. The results showed that: (1) The growth of I. aquatica was significantly affected by nutrient concentrations and light conditions, and the biomass of I. aquatica under nutrients enrichment (TN=2.37 mg/L, TP=0.046 mg/L) was 1.6 times higher than that of the in-situ water body (TN=0.66 mg/L, TP=0.028 mg/L), while the growth under 40% shading was 1.5 times more than that without shading; the growth of M. aquaticum was less affected by either nutrient or light conditions. (2) The nitrogen removal capacity of I. aquatica was significantly higher than that of M. aquaticum, with nitrogen removal efficiencies of 213.30 mg/(m2·d) and 44.23 mg/(m2·d) for I. aquatica and M. aquaticum under optimal conditions. (3) Nitrogen removal by I. aquatica was mainly through plant assimilation, accounting for more than 70% of the total nitrogen removal. The shading of 40% enhanced nitrogen removal through significantly increased assimilative nitrogen uptake and root denitrification rate of I. aquatica. For M. aquaticum, plant assimilation and denitrification each accounted for 50% of the total nitrogen removal. The research showed that the application of ecological floating bed technology could strengthen the nitrogen removal capacity of deep-water reservoirs, in which the growth of I. aquatica was more suitable for water bodies with higher nitrogen concentrations, and that 40% and 75% shading for I. aquatica and M. aquaticum floating beds respectively during summer would have better water purification effect. Therefore, the implementation of ecological floating bed technology with a variety of plants to enhance water denitrification in deep-water reservoir where riparian wetlands are scarce is a proven method to improve water quality. |
| Key words: ecological floating bed denitrification Qiandao Lake light nutrient concentration |
