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.

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.

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）.

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.

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。

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.

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。

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%。

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。

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。

污泥陶粒联合木本植物净化富营养化水体

以污泥、高岭土、粉煤灰为原料制备污泥陶粒,通过正交实验确定最佳制备条件,采用扫描电镜(SEM)、X射线衍射仪(XRD)对污泥陶粒进行表征,分别构建以木本植物小叶栀子、花叶杞柳和大白黄杨加陶粒的组合生态浮床,以研究陶粒联合木本植物对富营养化水体的净化效果及植物生长状况。结果表明,污泥∶高岭土∶粉煤灰=2∶3∶1、预热温度300℃、焙烧温度1050℃、焙烧时间15 min条件下制得的陶粒孔隙性较好,含有活性组分,适于做生态浮床基质。植物陶粒浮床对COD、TN、TP及NH_(4)^(+)-N的平均去除率较植物浮床分别提高了6.65%、15.17%、6.56%和11.42%,且植物生长也优于植物浮床。其中“花叶杞柳+陶粒”浮床综合净化效果最好。当陶粒投加量为25 g/L时,既能达到理想的处理效果,又能节约成本,具有一定的应用价值。

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。

低温条件下不同配置浮床净化太湖水体效果

文章研究了低温条件下不同生物配置的水生植物浮床、水生动物浮床、水生植物介质浮床、水生动物介质浮床和组合生态浮床对太湖水体氮、磷等污染物的去除规律,结果表明,组合生态浮床对各类污染物的综合去除效果最好。低温下植物对溶解态氮有较好的去除效果;人工介质较强的微生物富集作用使得其在低温下仍表现出一定的硝化反硝化作用。三角帆蚌通过滤食作用促进了颗粒性有机氮可溶化和无机化,有利于氮被植物和微生物利用,提高了组合生态浮床(IEFB)TN的去除效果。低温下植物单元的吸收和人工介质单元硝化反硝化作用是组合生态浮床除氮的主要原因。对TP研究表明,低温下三角帆蚌的滤食、人工介质的吸附拦截和微生物的同化作用是组合生态浮床除磷主要原因。考察了IEFB对微量有机物的去除,结果表明,IEFB 6 d微量有机物总峰面积下降了73.87%,是空白对照浮床的1.47倍。对三环[5.2.1.0(2,6)]癸-3-烯-10-酮、邻苯二甲酸二乙酯、邻苯二甲酸丁基酯2-乙基己基酯、氯芬磷6 d峰面积去除率达46.06%、36.45%、89.87%、48.25%,是空白对照浮床去除率的2.97、2.51、1.64、6.37倍。

基于生态浮床技术的广东省内河污染治理与水质改善研究

针对广东省内河污染问题,提出以生态浮床技术为主要治理手段,恢复水体生态环境。探讨生态浮床技术的原理和优势,分析广东省内河的污染现状,研究生态浮床技术的具体应用方式。选取广州市北部某内河作为研究案例,详细设计并构建了生态浮床系统。运行与维护结果表明,该技术能有效减少水体污染物,提高水体自净能力,具有实践推广价值。

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。

温度对生态浮床系统的影响

通过构建生态浮床净化临江河重污染河水,全面考察了温度对浮床系统的影响.结果表明,温度对生态浮床系统有明显的影响作用,对生态浮床系统氮、磷净化效果的影响呈抛物线型.在水温为2～29℃时,生态浮床对TN和TP的去除率随温度的增加而明显增加;当水温超过29℃时,系统对TN和TP的去除率随温度的增加呈下降趋势;且温度对TN去除效果的影响要大于对TP的影响.研究表明,浮床系统的最佳运行水温为25～29℃,此时浮床植物的平均株高为209.9cm,对氮、磷的平均累积量分别为69.84,19.73g/m2;浮床对TN和TP的去除率分别为38.7%～44.1%和38.6%～43.6%.

不同季节浮床美人蕉对水体氮素等污染物的去除

采用浮床无土栽培的方法,以人工模拟水槽为实验场所,在水槽内的富营养化水体表面种植美人蕉,通过植物的吸收和吸附作用,以及微生物的协同作用,去除水体中的氮素。实验结果表明,春季浮床美人蕉对水中氮素的去除效果较好,经过五天的处理,TN去除率约为58.4%;NH4+-N去除效果显著,2天内去除率达100%。与春季相比,秋季浮床美人蕉对氮素的去除效果有所下降,但去除规律大致相同,经过五天的处理,TN去除率为50.4%;对NH4+-N的去除效果仍很明显,4天内去除率可达100%。研究结果为浮床植物系统的全年运行提供了科学依据。

生态浮床对河口水质的净化效果研究

通过分析浮床建成前后、浮床撤除前后以及浮床边和开阔水道之间水质的差异,考察了浮床对河口水质的净化效果,并对净化机理进行了分析。结果表明,生态浮床具有很强的净化能力,经过浮床段后TN、TP和NH4+-N浓度均得到明显降低;浮床边的水质较好,浮床对TP、TN、NH4+-N的净去除率分别为10.4%、8.1%、18.1%;由于氮循环过程的复杂性,经过浮床段后NO3--N和NO2--N浓度反而显著升高;工程段水质的改善是湖水稀释、河流自净和浮床净化等综合作用的结果;撤除浮床后,对水体的净化效果大大降低,对TP、TN、NH4+-N的去除率仅分别为18.2%、9.2%、27.8%。