Spatial distribution of multielements including lanthanides in sediments of Iron Gate I Reservoir in the Danube River

Recent studies show that lanthanides (Ln) are becoming emerging pollutants due to their wide application in new technologies, but their environmental fate, transport, and possible accumulation are still relatively unknown. This study aims to determine major and trace elements including Ln in the Danube River sediment which either belong or close to the Iron Gate Reservoir. The Iron Gate Reservoir is characterized by accumulation of sediments as an effect of building hydropower dam Iron Gate I. The surface sediments were collected on the Danube River—1141 to 864 km and three tributaries along this waterway. Two samples of deep sediments were used for comparison. The results indicate the significant upward enrichment of Zn, Sb, Cr, Nd, and Dy in sediments belongs to the Iron Gate Reservoir. The sample 4-Smed is labelled as a hot spot of contamination with Zn, Cr, As, Sb, Nd, and Dy. Also, a trend of increasing concentration in the time period from 1995 to 2016 was found for elements Zn, Cr, and Ni in sediment samples in the Iron Gate Reservoir. Chemometric analysis shows the grouping of sample sites into clusters characterized by the following properties: (i) increased concentration of all measured elements (samples within the Iron Gate Reservoir); (ii) increased Cu concentration (11-Pek); and (iii) lower concentrations of the measured elements (deep sediments). The data presented hereby contribute to the monitoring of pollution of the River Danube sediments and give the first view of Ln profile in the studied sediments.

Velocity field and discharge measurements at the turbine inlet of Iron Gate 2 hydropower plant

<p>To define the performance characteristics of turbines in Hydropower Plants (HPP) accurate hydraulic, mechanical and electrical quantities are needed. The discharge is the most difficult quantity to measure and assess its uncertainty (Adamkowski, 2012). Traditionally, during field acceptance tests the discharge is measured using velocity-area method. Often, no direct flow measurements are possible and only index methods are used, with flow coefficients obtained during physical model testing. In the non-standard situations, with adverse flow conditions this may lead to unpredicted flow uncertainty.</p><p>             The system used at the Iron Gate 2 HPP for control flow measurement at the inlet of bulb turbine is presented in this paper. The HPP is situated on a Danube river, between Serbia and Romania and is operational from 1985. The HPP is equipped with 20 horizontal Kaplan low head bulb turbines. The physical model experiments (JČInstitute, 2006) have concluded that due to the upstream flow conditions, the incident water flow direction is not parallel to the turbines (depending on operating conditions and can be up to 40<sup>o</sup>) as was assumed during the turbine’s model tests, raising the question of used Winter-Kennedy’s method accuracy.</p><p>             To perform a control flow measurement, a modular velocity-area system was designed. The system can be installed at the intake of any turbine, upstream of the trash rack. It consists of the 14.5x3.1 m steel frame, shaped to minimize flow disturbances, which can be traversed vertically through the flow cross section (28 m). Due to the high incident angles and large vortices in the front of the trash rack, propeller current meters were not suitable. The novel spherical 3D electromagnetic velocity meter (EMVM) was developed (Svet Instrumenata), enabling fast and continuous measurements of all the velocity vector components, with low flow disturbance. The 15 EMVMs were mounted on the frame and connected into the measurement network. Redundant velocity measurement was done using 2 Nortek “Vector” ADVs (Nortek). The measurement network also comprises of 2 water level pressure transducers and 2 steel frame position transducers (UniMeasure). All measurements were synchronized with HPP’s SCADA, so turbine’s operational parameters were downloaded off-line and merged.</p><p>             During the 2020, measurement system was used on the two turbines. The velocity profile was measured using two strategies: incrementally, the steel frame was raised from the bottom (average depth of 26 m) in increments of ~1.0 m and kept for at least 10 min in fixed position, and continuous where the steel frame was traversed through the flow cross-section with a constant speed of 0.05 m/s. Uncertainty assessment procedure, specifically tailored for this application, yielded discharge measurement uncertainties between 1.02 % and 2.00 %  for incremental, and between 1.65 % to 2.79 % for continuous regime.</p><p>References</p><p>Adamkowski, A. (2012). Discharge measurement techniques in hydropower systems with emphasis on the pressure-time method. Hydropower-practice and application.</p><p>Jaroslav Černi Institute (2006). Scale model investigation of turbine runner inflow at an unfavorable angle at HPP „Đerdap II“, SDHI (in Serbian)</p><p>NORTEK: https://www.nortekgroup.com/products/vector-300-m</p><p>Svet Instrumenata: http://www.si.co.rs/index-e.html</p><p>UniMeasure: https://unimeasure.com/wp-content/uploads/2019/12/HX-EP-SERIES-CATALOG-PAGES-1.pdf</p>

Spatial Distribution of multielements including technology critical elements in sediments of the Danube River

Background The pollution of the second-longest European river (the river Danube) has been under monitoring and focused on various contaminants including metals/metalloids (Hg, As, Ni, Zn, Cu, Cr, Pb, and Cd), personal care products, technical additives, pesticides, pharmaceuticals, etc. Recent studies show that technology critical elements (TCE) – elements with a high supply risk and economic importance – are becoming emerging pollutants due to their wide application in new technologies. According to the European Union Water Framework Directive, sediments are one of the three major sources of river pollution. This study aims to determine major and trace elements including some TCEs in the Danube River sediment. The concentrations of the targeted elements in the surface sediments were discussed in the sense of the effect of building hydropower dam Iron Gate I and increasing the quantity of sediments in the Iron Gate gorge. Results The surface sediments were collected on the Danube River-km 1141 to 864 and three tributaries along this waterway. Two samples of deep sediments were used for comparison. Instrumental Neutron Activation Analysis was applied for quantification of 36 elements, with special attention to selected TCE belonging to lanthanides (La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Tm, and Yb). Spatial distribution is discussed (i) in the total pool of all analyzed elements and (ii) only lanthanides. For better understanding and to highlight a hidden relationship between targeted elements, multivariate statistical techniques (cluster analysis and principal component analysis) were applied to analyze the analytical data and to identify possible pollution sources. The obtained results of the targeted elements in the surface sediments were discussed in relation to the influence of hydropower dam Iron Gates I and the increasing quantity of sediments. Conclusion Overall results show increasing concentration of almost all investigated elements in the surface sediments from the Danube River-km 1112 to the dam. Sediment od the River Pek was separated as a location with extreme anthropogenic influence due to close vicinity of the copper mining site.

Enhancing Large Dam Safety Using IoT Technologies: A Case of a Smart Dam

This paper investigates how to transform a manual monitoring system into a smart environment using IoT technologies. Large dams are of huge importance as water reservoirs and potential energy sources primarily because of their use for electric energy generation. Monitoring and predicting dams' behavior are quite challenging. Due to a variety of limitations, environmental obstacles and dam system complexity, the application of RFID, Bluetooth, and IoT technologies has proven to be an adequate, affordable and reliable dam safety solution. This paper introduces a comprehensive model of dam safety management and monitoring based on pervasive technologies. The model described in this work has been applied within the large dam "Iron Gate 1", on the river Danube in the Republic of Serbia. The results show that the use of new technologies in the dam monitoring process can reduce human error and improve overall process.

Historical Toponyms Along ‘Termez - Iron Gate’ Trading Way

It is illuminated the historical toponyms, their origin, location and significance in the Termez and Iron Gate trade routes which is located in the territory of the Surkhandarya region, Republic of Uzbekistan in this article.