Water purification with sintered porous materials fabricated at 400℃ from sea bottom sediments

A sintering technology for preparing porous materials from sea bottom sediments was developed for use in water purification. The purpose of the present study was to develop methods for converting the sea bottom sediments dredged from Ago Bay into value-added recycled products. The sintered products fabricated at 400℃ were found to be very effective adsorbents for the removal of heavy metals.

Distribution of Macro-elements and Natural Radionuclides in the Bottom Sediments and Soils of the Catchment Areas of Small Lakes in the Baikal Region

The examination of macroelements and natural radionuclides in the bottom sediments of small lakes and soils in the catchment areas of the Baikal region allows for the study of the mechanism of inflow and the source of these materials.On the basis of the results of rentgenostructural analysis lake sediments are divided into four types:terrigenous,carbonate, terrigenous-carbonate and organogenic.Through the analysis of gamma-ray spectrometry and ato-

EFFECTS OF ANAEROBE IN SEA BOTTOM SEDIMENT ON THE CORROSION OF CARBON STEEL

This in situ corrosion study of steel in sea bottom sediment by the "Plate TransplantingBurying Method" (MD method ) showed that the corrosion rate of steel in sea bottom sediment with sulfur reduction bacteria (SRB) can be as high as ten times that in sea bottom sediment without SRB . The ex-periments in simulating sea bottom sediments with different concentrations of cultured SRB showed that theelectrochemical polarization behaviour of steel in sea bottom sediment with and without SRB were differ-ent SRB altered the polarization behaviour of steel significantly by acididfying the environment so that ap-parent hydrogen depolarization occurred and accelerated the corrosion of steel.

Wave-current bottom shear stresses and sediment re-suspension in the mouth bar of the Modaomen Estuary during the dry season

On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses （BSS） and their effect on a sediment resuspension. Swell induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI （wave-current interaction） is strong enough to re-suspend the coarse sediment.

Assessment of Cu, Pb and Hg Contamination in Bottom Sediments Of Surface Water in XuZhou

Pollution of heavy metals Cu,Pb and Hg is assessed using geo-accumulation index in this paper. The result shows that the bottom sediments of surface water in Xuzhou is polluted by these heavy metals to deferent degrees, of which the Jinma River is the most serious, and then the Kuihe River, the abandoned Yellow River, and the Jinghang Canal. The Yunlong Lake has also been polluted by Hg. The three kinds of heavy metals in the order of concentration is Hg>Cu>Pb. The pollution degree and the type of element is closely related with industrial structure in Xuzhou.

黄河水沙监测数据分析与模型构建

对黄河水沙监测数据进行分析研究,使用相关性分析、回归分析、Mann-Kendall非参数检验、奇异谱分析等方法构建数学模型.分析含沙量与各因素的关系、水沙通量变化规律、水沙通量趋势预测、河底高程变化规律预测等问题,并提出水沙通量监测的优化策略.在环境治理、调水调沙、防洪减灾等方面具有一定的现实意义.

基于浅地层剖面数据和改进地声模型的底质反演方法

浅地层剖面仪发射的声脉冲能够穿透海底面进入沉积层内部,其回波中携带了丰富的底质信息。地声模型是底质声学与物理性质关系的数学描述,广泛用于海底声学与地声反演研究。本文通过对浅地层剖面数据的处理、解译得到海底反射系数,与考虑底质松密影响的改进Biot-Stoll模型相结合,提出底质反演新方法并开展实例验证。研究结果表明:通过对浅地层剖面原始记录的读取、解译,提取反射波振幅,并结合设备声源级,可有效求取海底反射系数。通过引入相对密度改进孔隙度计算公式,进而在基于Biot-Stoll模型构建海底反射系数和底质平均粒径关系过程中进一步考虑了底质松密的影响。基于山东威海某海域及文献的算例均显示,本文提出的改进地声模型可缩小底质反演与实测结果之间的相对误差、提升基于浅地层剖面数据的海底底质地声反演精度。

A FVCOM-Based Unstructured Grid Wave, Current,Sediment Transport Model,I.Model Description and Validation

An effort was made to couple FVCOM (a three-dimensional (3D),unstructured grid,Finite Volume Coastal Ocean Model) and FVCOM-SWAVE (an unstructured grid,finite-volume surface wave model) for the study of nearshore ocean processes such as tides,circulation,storm surge,waves,sediment transport,and morphological evolution.The coupling between FVCOM and FVCOM-SWAVE was achieved through incorporating 3D radiation stress,wave-current-sediment-related bottom boundary layer,sea surface stress parameterizations,and morphology process.FVCOM also includes a 3D sediment transport module.With accurate fitting of irregular coastlines,the model provides a unique tool to study sediment dynamics in coastal ocean,estuaries,and wetlands where local geometries are characterized by inlets,islands,and intertidal marsh zones.The model was validated by two standard benchmark tests: 1) spectral waves approaching a mild sloping beach and 2) morphological changes of seabed in an idealized tidal inlet.In Test 1,model results were compared with both analytical solutions and laboratory experiments.A further comparison was also made with the structured grid Regional Ocean Model System (ROMS),which provides an insight into the performance of the two models with the same open boundary forcing.

Southern Jordan Coastal Sediments Quality Assessment at Aqaba Special Economic Zone/Red Sea

The bottom surface sediments at the southern part of the Jordanian coast of the Gulf of Aqaba have been studied. Samples were collected from 10 m depth at nine coastal stations which are located within two main zones: Marine Park Zone and Industrial Zone. Sedimentation rate, grain size oxygenation state, Loss on Ignition, hydrogen sulfide, calcium carbonate, total phosphorous, organic carbon, organic nitrogen, and heavy metals were analyzed to assess and evaluate the quality of bottom surface sediments. The sedimentation rate at the southern part of the Gulf has been affected by Khamassin winds from the south as a result of sand storm events in southern Jordan and adjacent regions. Floods and streams also played a vital role as a transportation agent of the sediments from the interstitial nearby areas to the Gulf. Also construction works played a minor role. Bottom surface sediments at the different sites were quite different in some chemical properties. Sediments from all stations other than the MSS were fine, gray-black and oxygen deficient. Sediments from the MSS and VC are whitish, better oxygenated and have higher calcium carbonate content since they are typically coral reef sediments coral reef sediments. Coral reef carbonate sediments are well known to have high organic nitrogen concentration as compared to silicate sediments, even those in close proximity. The concentration of phosphorous and calcium carbonate is attributed in the phosphate port to the phosphate by the generation of the dust and coral reef. Whilst, heavy metal concentration due to presence of major sources of metal pollution and intensive human activities. These include ship boat activities, domestic sewage discharges and phosphate rock particles from the phosphate port.

Hydro-Sedimentary Dynamics of the Grand-Popo Lagoon Located Upstream of the Mobile Embouchure “Bouche du Roy” in South-Western Benin

The problems of flooding, bank erosion and even the breaching of the barrier beach by the Grand-Popo lagoon are a concern in the south-western Beninese river-lagoon complex. The present study aims to improve the knowledge of the factors controlling the hydro-sedimentary functioning of this lagoon of Grand-Popo. It was based on bathymetric and sedimentological studies and the analysis of physical-chemical parameters of the water and allowed to know the morphology of the lagoon bottom and the distribution of sedimentary facies according to the intensity of the water current. The salinity of the lagoon waters shows a west-east gradient passing thus from 0‰ to 0.78‰ in the main direction of flow. Over the whole lagoon system, the average liquid flows vary from -38.499 to 159.13 m3/s. The bathymetry indicates depths varying from 0.4 to 6.5 m, revealing type V and type U lagoon bottoms which reflect acute bottom concavities marked by hollowing under the effect of strong currents or by sandy terraces resulting from the continuous input of sediments carried by the Mono River. These sediments are heterogeneously distributed in the lagoon bottom and vary from free sand to mud. Given the complexity of the factors that control the hydro-sedimentary functioning of the Grand-Popo lagoon, it is recommended that periodic hydrological and bathymetric monitoring be carried out to locate exceptional variations in water levels to prevent not only the risks of overflowing lagoon waters and the flooding that follows but also spectacular erosion of the lagoon banks.

Field Observation and Analysis of Wave-Current-Sediment Movement in Caofeidian Sea Area in the Bohai Bay, China

In order to study the mechanism of flow-sediment movement, it is essential to obtain measured data of water hydrodynamic and sediment concentration process with high spatial and temporal resolution in the bottom boundary layer （BBL）. Field observations were carried out in the northwest Caofeidian sea area in the Bohai Bay. Near 2 m isobath （under the lowest tidal level）, a tripod system was installed with AWAC （Acoustic Wave And Current）, ADCP （Acoustic Doppler Current Profilers）, OBS-3A （Optical Backscatter Point Sensor）, ADV （Acoustic Doppler Velocimeters）, etc. The accurate measurement of the bottom boundary layer during a single tidal period was carried out, together with a long-term sediment concentration measurement under different hydrological conditions. All the measured data were used to analyze the characteristics of wave-current-sediment movement and the BBL. Analysis was performed on flow structure, shear stress, roughness, eddy viscosity and other parameters of the BBL. Two major findings were made. Firstly, from the measured data, the three-layer distribution model of the velocity profiles and eddy viscosities in the wave-current BBL are proposed in the observed sea area; secondly, the sediment movement is related closely to wind-waves in the muddy coast area where sediment is clayey silt： 1） The observed suspended sediment concentration under light wind conditions is very low, with the peak value generally smaller than 0.1 kg/m^3 and the average value being 0.03 kg/m^3; 2） The sediment concentration increases continuously under the gales over 6-7 in Beaufort scale, under a sustained wind action. The measured peak sediment concentration at 0.4 m above the seabed is 0.15-0.32 kg/m^3, and the average sediment concentration during wind-wave action is 0.08-0.18 kg/m^3, which is about 3-6 times the value under light wind conditions. The critical wave height signaling remarkable changes of sediment concentration is 0.5 m. The results show that the suspended load sediment concentration is mainly influenced by wave-induced sediment suspension.

Distinguishing the main components of submarine groundwater and estimating the corresponding fluxes based on radium tracing method—taking the Maowei Sea for example

Submarine groundwater discharge(SGD)is an important part in the land-sea interactions,which mainly contains three components:submarine fresh groundwater discharge(SFGD),tidal flat recirculated saline groundwater discharge(tidal flat RSGD)and subtidal recirculated saline groundwater discharge(subtidal RSGD).In order to make a more accurate assessment of the impact of SGD on coastal ecological environment,it is necessary to distinguish the main components of SGD.In this study,the Maowei Sea,located in the northern part of the Beibu Gulf,was selected as the study area.Based on the radium(Ra)tracing method,we present a new analytical method for distinguishing the three main components of SGD in this area combined with field data.The average daily flow along the coastline of the Maowei Sea of tidal flat RSGD was slightly higher than that of SFGD,and both two were on the magnitude of 1×10^(5)m^(3)/d.The average daily flow for the subtidal RSGD of the entire subtidal zone of the Maowei Sea reached to the magnitude of 1×10^(6)-1×10^(7)m^(3)/d.The long-term variation trend of terrestrial SGD is a valuable information for the study of the influence of terrigenous material on the coastal ecological environment.Based on the results of four sampling periods,it is found that the fluxes of SFGD and tidal flat RSGD in the Maowei Sea had good linear correlation with the net precipitation.As an example,January 2015 to August 2022 were selected as the study periods,and the variation trends of SFGD and tidal flat RSGD were calculated by linear function with net precipitation as the independent variable.The results showed that the flux of tidal flat RSGD was slightly higher than that of SFGD,and the difference between the two is larger in flood season while smaller in dry season.In general,in the coastal range of China,the total SGD flux in the Maowei Sea area is at a high level,and the SFGD flux is at a medium level.

旋挖灌注桩泥浆悬浮法机械清孔施工技术研究

泥浆护壁旋挖钻孔灌注桩施工工艺是采用人工制作成品泥浆来置换孔中挖出的土、石,利用泥浆对孔壁的静压力和泥浆在孔壁上形成的泥皮来有效防止孔壁坍塌,再利用水下混凝土置换孔内泥浆的成桩工艺。结合桩基施工经验,以某项目泥浆悬浮法机械清孔旋挖施工技术为例,对旋挖钻孔灌注桩施工流程给予细致探讨,为类似工程提供相关经验借鉴。

噪声HVSR法在OBS探测中的应用——以珠江口外海OBS台阵为例

噪声谱比法(horizontal-to-vertical spectral ratio,HVSR)通常用于确定沉积层的厚度,而应用于海底地震仪(OBS)以获取海底沉积厚度的研究较少.本文将HVSR法应用于珠江口外海域OBS台阵中,验证了该方法用于OBS探测中的可靠性.通过对珠江口外海27台OBS收集的三分量地震噪声记录进行处理,得到了所有台站的HVSR曲线.有23台OBS的HVSR曲线可获取与沉积层厚度相关的峰值频率,通过经验公式可以计算得到沉积层厚度.结果显示,珠江口外海域沉积层(新生代地层)厚度范围为100~3500 m,研究区东南部沉积层远厚于西北部,且沉积厚度受到NEE向滨海断裂带控制.本文获得的结果与以往依靠反射地震剖面和钻井等获得的沉积层厚度结果基本一致.进一步分析发现研究区新生代地层具有多层结构,大部分HVSR曲线在5~12 Hz存在振幅最大的波峰,认为是与第四系厚度相关的峰值频率,继而确定第四系厚度为20~50 m.本研究拓展了HVSR法的应用领域,为获取海底沉积层厚度提供了一种新的可靠方法.

太湖湖泛常发区底泥特征及指示性细菌的研究

为探究太湖湖泛常发区环境下表层底泥细菌的特点及其与环境因子的相关性,运用高通量测序的方法对太湖中湖泛常发区域以及普通水体区表层底泥细菌及环境理化指标进行检测.结果表明:①湖泛区上覆水中的TN、TP分别是普通区的2.4倍和2倍;DO(溶解氧)显著降低.②湖泛区表层底泥细菌丰度以及多样性相比普通区有显著降低(P<0.05),湖泛区4个点位(#1、#2、#3、#4)的Simpson指数均高于0.003.③从细菌门的层次来看,拟杆菌门(Bacteroidetes)在湖泛区的优势地位显著上升,#1点位已经成为第二优势菌门(占比16.3%),且随机森林分析表明拟杆菌门是两组样本之间差异性重要值最高的门类.④从属的层面来看,在湖泛区占比显著升高的Bacteroides、Bacteroidetes vadinHA17_norank、Lentimicrobiaceae_norank均为拟杆菌门下的厌氧菌属(P<0.05),同时相关性分析也表明Steroidobacteraceae_uncultured与上覆水TN、TP以及TOC含量呈显著正相关,与DO呈显著负相关.本研究为未来环境监测中增加微生物方面的测评指标存在一定的借鉴意义.

袖阀管注浆技术在管桩引孔加固中的应用分析

文中阐述了预应力高强混凝土管桩采用引孔法施工出现的问题—管桩入土深度小于引孔深度,分析了引孔后管桩入土未及孔底的原因,制定并实施对于引孔后预制管桩进行袖阀管注浆的加固处理方案。经检测结果显示,袖阀管注浆技术可有效解决引孔后管桩施工出现的此类问题,对桩底沉渣及桩周松弱土体具有显著的加固作用,可规避桩身承载力无法满足设计要求的风险。

基于浅地层剖面仪的鄱阳湖水下沉积地形探测与分析

鄱阳湖是我国重要的淡水和砂石资源提供地,其水下沉积地形现状一直是学术界研究的重点。该文借助浅地层剖面探测手段对鄱阳湖水下地形与沉积特征进行了探测,通过分析32条浅地层剖面测线资料发现,鄱阳湖水深变化幅度为0.16~23.71 m,入江水道与主湖区西北部相对较深;松散沉积物厚度变化范围为0~8.73 m,主湖区中部松散沉积物较厚,估算松散沉积物总体积约3.02 km^(3)。为检验浅地层剖面探测数据的可靠性,2022年9月在主湖区开展了浅钻探测工作。通过与前人的相关研究对比发现,大规模采砂活动能够对鄱阳湖水下地形产生显著影响。该文较全面地揭示了鄱阳湖水下地形现状与沉积特征,得出的结论与建议对相关研究与管理工作具有重要的参考价值。