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.

Mechanical,expansion and rheological properties of circulating fluidized bed fly ash based ecological cement:A critical review

Circulating fluidized bed fly ash(CFBFA)is a solid waste product from circulating fluidized bed(CFB)boilers in power plants,and the storage of CFBFA is increasingly become an environmental problem.Previous scholars have made contributions to improve the resource utilization of CFBFA.Especially,ecological cement is prepared by CFBFA,which is more conducive to its large-scale utilization.In recent years,a lot of effort has been paid to improve the properties of ecological cement containing CFBFA.In this work,the physicochemical properties of CFBFA are introduced,and recent research progress on the mechanical,expansion,and rheological properties of CFBFA based ecological cement(CEC)is extensively reviewed.The problem of over-expansion of f-CaO is summarized,which limits the scale application of CFBFA in ecological cement.Hence,the challenge for f-CaO in CFBFA to compensate for cement volume shrinkage is proposed,which is beneficial to the utilization of CFBFA in ecological cement,and the reduction of CO_(2) emissions from the cement industry.In addition,the environmental performance,durability,and economy of CEC should be valued in future research,especially the environmental performance,because the CFBFA contains heavy metals,such as Cr,As,which may pollute groundwater.

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.

Research on Purification of Domestic Sewage by Artificially Strengthened Ecological Filter Bed in North China

Artificially strengthened filter bed is an innovative wastewater treatment technology based on the coupling of eco-contact oxidation filters and artificial wetlands purification mechanism.By small scale laboratory equipment,the effects of cascade aeration,filter type,filter clogging and other ecological factors on the operation effect of artificial filter bed were studied.As indicated by the results,the pretreatment of cascade aeration had obvious effect and could satisfy the oxygen requirements of artificially strengthened ecological filter bed.Through the analysis on the purification results of volcanic and gravel filter,the effluent quality of volcanic filter was better than that of gravel filter.With the advantages of low operations costs and good effluent quality,the artificially strengthened ecological filter bed has great value to be popularized in North China.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

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。

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.

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。

顺层变质岩坡稳定性评价与生态治理方案

为了探究鄂西北变质岩区不稳定斜坡滑崩地质灾害的成因机制和生态治理模式,以三用塘顺层变质岩不稳定斜坡为研究对象,在查明灾害体地质与变形特征的基础上,分析了其可能的破坏模式与主要影响因素,深入探究了顺层变质岩坡渐进式变形破坏的成因机理。采用极限平衡等方法对不稳定斜坡进行了稳定性分析评价,结果表明,该斜坡体处于不稳定状态。基于地质灾害生态治理理念,提出了削方整形、护脚墙、格构锚固、截排水沟、生态绿化与监测等综合防治措施。通过工程实施及效果监测表明:该治理方案不仅有效地消除了三用塘滑崩地质灾害安全问题,而且取得了良好的环境绿化与美化效果。其综合防治措施,特别是将地质灾害防治与生态绿化融为一体的生态治理模式可为同类顺层变质岩不稳定斜坡的加固与坡面防护提供借鉴。

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.

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。

海草床的固碳潜力及其生物量监测方法研究进展

海洋是地球上最大的活跃碳库,包括浮游生物、细菌、海藻、海草床、盐沼和红树林等在内的海洋生态系统固定了全球50%以上的碳,每年可吸收约30%的人类活动排放到大气中的CO_(2),其碳储量分别是陆地碳库和大气碳库的20倍和50倍,是地球上最高效的碳汇,在应对全球气候变化、保护生物多样性和实现可持续发展等方面发挥着重要作用[1].

曹妃甸海草床生态特征及限制因子研究

通过开展曹妃甸海草床的分布、生物学特征、水环境和底质环境要素等调查研究工作,划定海草床分布区,对覆盖度进行分级,分析研究海草床生态特征及关键环境影响因子特征,为查明曹妃甸海草床资源环境家底、保护区划定、海洋生态修复及蓝碳研究工作提供技术参考。结果显示,曹妃甸海草床主要优势种类为鳗草,平均株高75.00±6.15 cm/shoot,且不同站点之间有差异;总平均茎枝密度为261.26±48.50 shoots/m^(2),总平均地上和地下生物量分别为302.53±71.79 g DW/m^(2)和114.71±27.40 g DW/m^(2)。海草床分布区面积42.90 km^(2),其中密集区、较密集区、一般区、较稀疏区和稀疏区分别占比为13.09%、12.93%、18.82%、18.75%和36.40%,海草分布在北部和南部两个区域,其中密集区与较密集区多分布在北部区域;草床区和裸沙区水环境差异不明显,底质环境差异较大;水温、营养盐、透光度、水流及人类工程活动是影响曹妃甸海域海草生长的关键因素。

生态砾石床+碎石湿地在城市劣五类水体治理中的应用

为解决北方寒冷地区城市劣Ⅴ类河道的问题,采用“生态砾石床+碎石湿地系统”的组合工艺,将来水引入湿地进行净化。结果表明:该工艺对北方城市劣V类水体处理效果明显,系统具有较强的耐冲击能力,可降低冬季气温对湿地运行的影响。原水COD≤80 mg/L、NH_(3)-N≤3.0 mg/L、TP≤0.6mg/L时,该工艺系统对COD、NH_(3)-N、TP的平均去除率分别可达59.54%、60.62%和33.42%,出水主要指标满足《地表水环境质量标准》(GB 3838-2002)Ⅴ类水体限值。运行后每年削减COD排放量为1204.50 t,NH3-N排放量为40.15 t,TP排放量为8.03吨,明显改善了河道的生态环境。