Review of Ecological Floating Bed Restoration in Polluted Water

Using Ecological Floating Bed (EFB) to purify polluted water is a process of ecological restoration at virgin position, as well as a complicated physical, chemical and biological process. Its core is utilizing aquatic plants and root’s microbes to absorb nitrogen and phosphorus elements, degrade organic matter and enrich heavy metal. EFB has been applied to some water pollution control projects at home and abroad, and has got several achievements. However, there are some factors influenced the removal rate of pollutants, including plants, temperature, seasons, processing time, coverage and initial concentration of pollutants. In the future, the development orientation has been prospected from plant and its combinations, the transformation of EFB structure and the utilization of aquatic resources, and probed the technology of EFB’s building and management, to implement the win-win of landscape benefit and ecological function.

Function and Screening of Plants in Ecological Floating Bed Applied in Treating Rural Domestic Wastewater

With the construction of new countryside and the development of people's living standard,the environmental problems caused by rural domestic sewage gradually attracts more attention. Ecological floating bed is one of the effective techniques for treating rural domestic sewage. Building different types of ecological floating beds according to the surrounding environment characteristics in rural areas could treat rural domestic sewage with low operation cost,simple management and convenient maintenance,and could obtain a certain economic benefit as well. Therefore,ecological floating bed get fast development in treating rural domestic sewage. The screening of plants would be vital as an important role. Assembling different plants by choosing those with ornamental function,economic benefit and strong decontamination ability according to the surrounding environment and characteristics of domestic waste water along with the seasonal features of plant growth could take full advantages of ecological floating bed.

Influence of artificial ecological floating beds on river hydraulic characteristics

The artificial ecological floating bed is widely used in rivers and lakes to repair and purify polluted water. However, the water flow pattern and the water level distribution are significantly changed by the floating beds, and the influence on the water flow is different from that of aquatic plants. In this paper, based on the continuous porous media model, a moveable two-layer combination model is built to describe the floating bed. The influences of the floating beds on the water flow characteristics are studied by numerical simulations and experiments using an experimental water channel. The variations of the water level distribution are discussed under conditions of different flow velocities（ v= 0.1 m/s, 0.2 m/s, 0.30 m/s, 0.4 m/s）, floating bed coverage rates（20%, 40%, 60%） and arrangement positions away from the channel wall（ D= 0 m, 0.1 m, 0.2 m）. The results indicate that the flow velocity increases under the floating beds, and the water level rises significantly under high flow velocity conditions in the upstream region and the floating bed region. In addition, the average rising water level value（ARWLV） increases significantly with the increase of the floating bed coverage rate, and the arrangement position of floating beds in the river can also greatly influence the water level distribution under a high-flow velocity condition（v ？0.2 m /s）.

Nutrient concentration variations during Oenanthe javanica growth and decay in the ecological floating bed system

The ecological floating bed system is a natural alternative to technical methods of wastewater treatment and involves complex processes induced by plants or microorganisms in the wastewater. This study aimed to identify nutrient concentration variations during Oenanthe javanica （Blume） DC growth and decay in the ecological floating bed system. Results showed that the third-order polynomial equation was suitable to describe pollutant concentration changes, showing that the effect of O. javanica ecological floating bed system on polluted water could be divided into the purification phase and decay phase. During the purification phase, nutrient concentrations rapidly decreased because O. javanica influenced water microbial communities and water physical parameters （i.e., dissolved oxygen, pH, and temperature）, and had a direct uptake of nutrients. However, during the decay phase, nitrogen and phosphorus concentrations in the plant tissues decreased, and these lost nutrients ultimately transferred to water and led to water quality deterioration. Results also showed that the uptake and storage of O. javanica in nutrients were temporary and the plant served only as media of the nutrients removed from the water. Under these circumstances, harvesting was an appropriate intervention to improve the treatment efficiency of O. javanica ecological floating bed system.

曝气-生态浮床联合技术净化河道水质效果及机理研究

为提升东减河水体质量,探究了曝气增氧-生态浮床联合技术对河道水体中氮磷及有机物的去除效果及机理.实验结果表明,联合技术对主汛期河道水体的COD去除率达到65%,总氮和磷酸盐去除率分别达到72%和46%.常规水质指标的相关性分析得出,氨氮、硝酸盐和亚硝酸盐是水体富营养化的主控因子.河道水温和藻类生长呈显著正相关,和溶解氧呈显著负相关.同时,在7—9月河道表层沉积物的有机氮和有机磷矿化释放作用增强且具有持续性.这些是造成该时段河道水质状况较差的关键因素.曝气-生态浮床联合技术既可以有效地去除河道水体中氨氮、总磷等污染物,还可以提高水体溶解氧含量,抑制水中藻类的生长.联合技术增加了河道底泥细菌群落的多样性和功能菌群的丰度,多种丰度较高的菌属与脱氮更为相关.其中脱氮功能菌有Thiobacillus、Sphingopyxis、Nitrospira、Pseudomonas、Thermomonas.除磷功能菌有Bacillus、Rhodobacter、Acinetobacter.同时检测出高丰度的黄杆菌属(Luteolibacter)是良好水质水体的指示生物.

增强型生态浮床填料筛选及工况优化

生态浮床作为一种经济、环保的黑臭水体处理工艺得到广泛应用,但其处理能力受制于植物根系深度及表面积。通过悬浮球、生物绳、弹性和组合填料分别与间种的粉绿狐尾藻(Myriophyllum aquaticum)和西伯利亚鸢尾(Iris sibirica)植物构建生态浮床,探究不同填料对生态浮床效能的强化作用及微生物机制;并在优选填料的基础上进一步探究优选填料的最优添加工况及其强化下浮床对污染物去除的动力学模型。填料优选实验结果显示,生物绳填料对COD、氨氮和总磷的去除率最佳,分别为>99%、43.85%和14.03%;高通量测序分析显示,生物绳填料表面生物膜微生物丰富度最高、物种组成分布最均匀、微生物多样性最高,且生物绳填料可定向富集Flavobacterium、Exiguobacterium、Chryseobacterium、Microbacterium、Caulobacter等脱氮除磷相关功能菌。生物绳工况优化结果显示,修复轻度黑臭水体的最佳生物绳填料投加量为12.5 m/m^(3),其对COD、氨氮和总磷的去除率分别为96.4%、38.5%和56.6%;动力学模型拟合显示,一级动力学模型能更好地拟合生物绳强化生态浮床的氨氮及COD降解规律。

Coupling of the flow field and the purification efficiency in root system region of ecological floating bed under different hydrodynamic conditions

The artificial ecological floating bed is a commonly adopted in situ treatment technique for repairing and purifying polluted water. The plant root system of the floating bed is the primary region to absorb and degrade the pollutant of water. Its inner flow field characteristics and the interactive water quantity with the surrounding water greatly impact the purification efficiency of the floating bed. In this paper, the particle image velocimetry （PIV） technology and the boundary velocity direct extraction method are used to study the velocity distribution of the root system region by numerical simulations and experiments in an experimental water channel. A pollution removal rate （PRR） evaluation model is built to calculate the PRR by coupling with the flow velocity field of the root system region. The variations of the total pollutant removal rate （TPRR） are discussed for different center distances （L =0.30 m, 0.45 m, 0.60 m）, flow velocities （v= 0.007 m/s, 0.015 m/s, 0.025 m/s, 0.040 m/s, 0.055 m/s, 0.070 m/s） and root system porosities （P = 54.73%, 68.33%, 79.17%）. The results indicate that the position arrangement of the floating beds influences the TPRR significantly, and the distance should be limited in a reasonable range for a high purification efficiency. Moreover, the root systems with higher porosity （P = 68.33%, 79.17%） have higher TPRR value than a lower porosity root system （P = 54.73%） within a certain flow velocity range, and the higher porosity root system has less fluctuation of the TPRR value than a lower porosity situation within a wide flow velocity range. Furthermore, under the same center distance condition, the lower flow velocity condition brings about a significantly higher TPRR value than the higher flow velocity situation.

东南丘陵山区深水水库两种浮床植物脱氮效率对比研究

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,开展了原位模拟实验对比研究,探究不同营养盐浓度和光强下两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=0.66mg/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达到213.30和44.23 mg/(m^(2)·d)。(3)空心菜去除氮主要以植物同化作用为主,占70%以上TN去除量,40%遮光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增强了氮的去除能力;粉绿狐尾藻同化吸收和反硝化脱氮作用各占50%左右,以遮光75%下脱氮效果最好。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。

内陆河流域浮床植物根际微生物群落特征与比较

为研究内陆河流域不同浮床植物的根际微生物群落结构、多样性、潜在生态功能及其差异,采集了位于沱江二级支流赤水河生态浮床上的风车草(Cyperus involucratus)、黄菖蒲(Iris pseudacorus)、再力花(Thalia dealbata)、鸢尾(Iris tectorum)、美人蕉(Canna indica)、梭鱼草(Pontederia cordata)6种植物生长旺盛时期的根系样本,通过细菌16sRNA片段高通量测序和生物信息学手段,分析了微生物群落结构组成、生物多样性以及潜在的生态功能。结果表明,变形菌门(Proteobacteria)在6种浮床植物根际细菌中占绝对优势,丰度达47.5%~72.2%,在植物生长环境较为相似且空间距离较近的情况下,不同浮床植物根际微生物属水平优势种群丰度差异仍较大。微生物群落多样性由大到小依次为鸢尾、美人蕉、黄菖蒲、风车草、再力花、梭鱼草,同科同属的黄菖蒲和鸢尾根际细菌组成相对较为相似。风车草根际硝化/反硝化功能菌群丰度更高,梭鱼草根际芳香族化合物降解功能菌群丰度显著高于另外5种植物。根长、株高和生物量更大的植物根际微生物中芽殖杆菌属丰度显著更高,植物生长指标与部分根际细菌氮转化存在正相关关系。研究结果可为浮床植物根际微生物群落研究和生态浮床的建设优化提供参考。

海蓬子(Salicornia europaea)生态浮床对富营养化海水的净化效果研究

因陆源污染输入和沿岸养殖业发展,我国近岸和入海口海域富营养化严重。该研究利用海蓬子(Salicornia europaea)高耐盐碱性、潮汐带生长的特点,通过浮床栽培探究了其对富营养海水的净化效果。实验构建褐牙鲆(Paralichthys olivaceus)养殖池和浮床净化池的循环水净化系统,模拟持续污染的富营养化海水环境。通过在浮床上移植海蓬子幼苗,测定不同水体中氨氮(NH_(4)^(+)-N)、硝态氮(NO_(3)^(-)-N)、亚硝态氮(NO_(2)^(-)-N)和磷酸盐(PO_(4)^(3-)-P)浓度4种营养盐指标的变化情况及植物存活、生长状况,研究海蓬子的净化效果。实验结果表明,海蓬子对NH_(4)^(+)-N吸收效果显著(P<0.05),在12 h的水力停留时间下最高去除率为32.97%;对NO_(2)^(-)-N的净化效果显著(P<0.05),最高去除率为35.66%;对PO_(4)^(3-)-P和NO_(3)^(-)-N有去除效果,但不显著;浮床上的海蓬子存活率达93%以上,植株有明显生长,25 d总体长度增长12%,鲜重增加102%,干重增加83%。研究结果说明海蓬子可以作为生态浮床的工具植物,对近岸和入海口富营养化海水进行净化,为海洋生态环境保护提供技术支撑。

农田退水中氮磷与吡虫啉的光催化水循环协同净化试验研究

为探究光催化和水循环协同净化氮磷和吡虫啉污染的效果,设计了空白对照、水循环和光催化水循环3组生态浮床系统、6个处理组对2种模拟农田退水(氮磷退水、氮磷和吡虫啉复合污染退水)进行了试验研究。试验结果表明:水体循环能增强浮床系统对氮的去除效果,7 d后氮磷退水的水循环浮床水体中氨氮和硝氮去除率较空白对照浮床分别提升了5.5%和27.1%;增加光催化的净化技术可加快氨氮硝化,氮磷退水的光催化水循环浮床水体中氨氮和硝氮去除率较空白对照浮床分别提升了26.2%和20.3%;吡虫啉会影响水循环浮床系统对氮磷的净化效果,TiO_(2)光催化复合陶粒对吡虫啉有良好的氧化降解效果,同时对氮磷和吡虫啉复合污染有显著净化效果;氮磷和吡虫啉复合污染退水的光催化水循环浮床降解了58.2%的吡虫啉,水体中氨氮、硝氮和磷酸盐去除率较未添加吡虫啉的水循环浮床分别提升了72.4%、15.0%和14.8%。

不同生态浮床对水体氮磷的净化效果及机理探讨

[目的]研究不同生态浮床对水体氮磷的净化效果及机理。[方法]通过构建空心菜-生物膜组合生态浮床,与对照组和空心菜浮床组比较对富营养化水体氮磷的去除效果,分析不同生态浮床的植物根系微生物的生物量、氮磷吸收量及去除贡献率,探讨生态浮床的氮磷去除机制。[结果]与空心菜浮床相比,组合生态浮床对氮磷污染物的去除效果更好,TN、TP、NH_(4)^(+)-N、NO_(3)^(-)-N平均去除率分别为71.35%、70.05%、83.17%、85.83%,较空心菜浮床提高了13.92%~21.08%;在氮磷去除过程中植物根系充当“载体”,富集大量的微生物,形成根系生物膜,而组合生态浮床根系生物膜的微生物生物量显著大于空心菜浮床(P<0.05),表明载体生物膜对植物根系微生物的富集和生长有显著促进作用;空心菜浮床和组合生态浮床中植物对氮磷的吸收量均有限,氮去除贡献率分别为25.56%、20.24%,磷去除贡献率分别为5.99%、4.18%,表明植物吸收作用不是浮床系统氮磷去除的主体。[结论]生态浮床对水体氮磷的去除主要依靠微生物转化作用,组合生态浮床的微生物生物量较大,可有效提高水质净化效果和系统稳定性。

组合生态浮床对城市河流缓流水体净化试验研究

采用由不同植物和生物载体组成的组合生态浮床应用于城市污染河道,考察了其对水体中污染物的去除效果。结果表明:组合生态浮床对水体中COD、氨氮、TN和TP都有一定的去除效果,其70 m沿程去除率平均分别达22.3%、23.6%、21.6%和9.7%。其中,美人蕉与碳素纤维生态草组合对高浓度水体中COD、氨氮、TN和TP的去除效果最为显著,去除率分别为5.56%、14.2%、10.5%和9.7%;不同植物在低浓度水体中表现出较好的去除效果,其中梭鱼草对COD和TP的去除效果显著,去除率分别达10.04%和11.1%,黄菖蒲对TN的去除率达7.2%,千屈菜对TP的去除率达11.1%,而阿科蔓生态基对低浓度水体中污染物的去除效果甚微。目前,城市河道水质受点源、面源等因素影响,污染物浓度变化较大,组合生态浮床能够适应水质的变化,可以有效改善污染河道水质。

人工生态浮床技术在城市水环境治理中的应用研究

城市可持续发展离不开生态环境建设,水环境治理是城市生态环境建设的重要环节。本文结合实际案例详细研究人工浮床技术在城市河道黑臭、河湖富营养化等水环境问题中的应具体应用及效果,以期能够促进城市更好地开展生态环境建设,更好地实现可持续发展。

海马齿生态浮床对金刚虾养殖环境的净化

为考察海马齿对金刚虾养殖水体的净化效果,对驯养后的海马齿茎叶主要成分进行测定,并分析金刚虾养殖中海马齿生态浮床对水体水质的影响。结果表明,海马齿的水分和灰分含量较高,其所含矿物质元素丰富,常见重金属未超标;铺设了海马齿生态浮床的金刚虾养殖池实验组的各氮磷指标的去除率比对照组高出9%~68%不等,对水体中氮、磷等相关成分有较明显的净化作用。显著性分析表明,是否使用海马齿生态浮床对水体中的氮磷指标有显著差异或极显著差异的影响。动力学拟合表明,对总磷和总氮的净化符合一级动力学模型,对硝酸盐、亚硝酸盐、氨氮在实验的前半段(分别为1~13、1~16、1~24 d)较符合一级动力学模型,后进入降解平台期。

某工业园区尾水组合式深度处理工艺研究

构建了一种以表面流人工湿地、垂直流人工湿地、潜流人工湿地、生态浮岛/人工水草立体生态技术、生态浮岛/水底森林立体生态技术等为主体的组合式工艺,深度处理了某工业园区污水处理厂尾水.结果表明:当水力停留时间为72 h时,进水COD、氨氮、总磷和总氮为21.9~41.2、0.51~4.21、0.06~0.31、8.79~14.2 mg·L^(-1)时,出水水质优于《地表水环境质量标准》(GB 3838—2002)准Ⅳ类标准.该组合式工艺可为工业园区污水处理厂尾水深度处理提供一定的参考.

不同植物组合的生态浮床对浅水富营养化湖泊水质净化效果及浮游动物群落结构的影响

为探究不同植物组合的生态浮床对浅水富营养化湖泊的水质净化效果及浮游动物群落结构的影响,于2021年6月对太湖梅梁湾示范区内已实施围网和围隔设施下的不同植物组合[美人蕉(Canna indica)+菖蒲(Acorus calamus)+芦苇(Phragmites australis)和美人蕉(Canna indica)+水芹(Oenanthe javanica)+慈姑(Sagittaria sagittifolia)]的生态浮床中浮游动物群落结构进行了调查。结果表明:生态浮床对浅水富营养化湖泊水质的净化效果良好,围网及围隔修复区较对照区总氮(TN)、总磷(TP)、叶绿素a(Chl-a)和高锰酸盐指数(COD_(Mn))等水体营养盐指标均显著降低(P<0.05),水体透明度显著上升(P<0.05);围网及围隔修复区域浮游动物种类数由对照区域的23种增加到39种,且由单一耐污种转变为多种类共存,其中,围网修复区内植物组合1(美人蕉+菖蒲+芦苇)的生态浮床浮游动物生物量及丰度显著高于对照区(P<0.05),表明修复区比对照区具有更强的浮游动物多样性恢复能力;冗余分析显示,Tur、Chl-a、COD_(Mn)和pH是影响浮游动物群落变化的主要环境因子;不同植物组合的生态浮床均在净化水质的同时提高了浮游动物密度和生物量。研究表明,浅水富营养化湖泊中置入两组不同植物组合的生态浮床,均可改变浮游动物群落结构,进而改善水环境原位修复效果,尤其以围网设施下美人蕉+菖蒲+芦苇的植物组合修复效果最好,本研究结果可为浅水富营养化湖泊水环境保护和水生生物资源恢复提供科学依据。

强化生态浮床净化黑臭水体研究

采用装载不同类型填料的生化物化耦合强化生态浮床处理低碳氮比黑臭水体。构建了Fe-C微电解强化生态浮床(ICEFB)、海绵铁微电解强化生态浮床(SIEFB)、沸石强化生态浮床(ZEFB)和生态浮床(EFB)四组反应器,比较不同浮床系统的脱氮除磷效果,考察DO质量浓度和进水NH_(4)^(+)-N质量浓度对氮、磷等营养盐去除效果的影响。结果表明,铁微电解填料的引入显著提高了生态浮床的脱氮除磷能力,与ZEFB和EFB相比,SIEFB和ICEFB具有较高的养分去除效率。在DO为2 mg/L、进水NH_(4)^(+)-N质量浓度为30 mg/L时,SIEFB对NH_(4)^(+)-N的去除率和去除负荷分别为99.33%和62.96 g/(m^(3)·d),TN的去除率和去除负荷分别为64.42%和56.78 g/(m^(3)·d),TP的去除率和去除负荷分别为88.51%和10.73 g/(m^(3)·d)。SIEFB的SND效率最高,为84.80%,具有较好的同步硝化反硝化效果。动力学研究结果表明,生态浮床系统内的NH_(4)^(+)-N的降解过程符合准零级动力学方程,TN和TP的降解过程符合准一级动力学方程。综上所述,海绵铁和Fe-C微电解是行之有效且有应用前景的生态浮床强化技术。

不同植物景观配置对河道污染水体的净化治理效果研究

经济快速发展的代价是环境污染,目前已提出多种针对污染水体的净化方法,但大部分不适用于中国国情,不具备高经济性,为此提出不同植物景观配置对河道污染水体的净化治理效果的研究分析,综合分析中国国情和河道污染情况,以生态浮床技术作为净化治理手段,探究不同植物景观配置下河道的化学需氧量、氮素、磷素污染参数值变化情况,并测量河道pH值治理前后的数值,得出在不同配置的净化效果。经实验结果表明,组合配置比单株植物的净化效果强,其中第3组水葫芦、再力花、慈姑以及水芹配置的净化效果最好。

养殖尾水浮床处理系统水生植物根际细菌的氮循环作用机制

为探讨养殖尾水处理中浮床水生植物根际细菌对水体氮循环的影响机制,采用16S rRNA基因扩增子测序和宏基因组测序技术方法,对浮床水生植物黄花鸢尾(Iris wilsonii C.H.Wright)根际细菌、水体细菌的群落结构及其与氮循环相关的功能基因丰度差异特征进行了研究。结果表明:生态浮床水生植物根际细菌以变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、Patescibacteria门和拟杆菌门(Bacteroidota)为主要优势门类;在属水平上,有10种关键功能菌属在氮素迁移转化关键过程中发挥了重要作用;与水体相比,水生植物根际细菌多样性较高,氮代谢活动更为活跃(P<0.05),且主要参与碳代谢、转运蛋白、细菌双组分调节系统和群体感应等代谢功能途径;根际细菌固氮功能基因(nifH、nifD和nifK)、硝化作用功能基因(hao)、反硝化作用功能基因(nirS、norB和nosZ)、异化/同化硝酸盐还原基因(napA、nrfA、nirB和nasA)及其6个氮循环关键酶的相对丰度均显著升高(P<0.05)。研究表明,生态浮床水生植物根际的氮素周转能力强于周围水环境,其生物脱氮的最主要方式是反硝化和异化硝酸盐还原过程。