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Typical measures for integrated treatment
Published in Xiaoling Lei, Bo Lu, Integrated Water Environment Treatment, 2021
At present, the sediment deposition is very serious in the backwater area of the Yangtze Three Gorges channel. Meanwhile, pollutants from surrounding water bodies of the Three Gorges Reservoir Region enter the Three Gorges Reservoir Region under the combined effects of point source pollution and non-point source pollution, then the pollutants enter the sediments as time goes on, resulting in the sediment deposition and pollution in the Three Gorges Reservoir Region. Sediments may release pollutants into water due to the sediment resuspension during traditional engineering dredging process, resulting in water eutrophication. Therefore, a reasonable and feasible environmental dredging construction technique is badly in need to reduce the sediment pollutant release into water, so as to achieve coexisting channel dredging and environmental benefits. Environmental dredging is a dredging method that combines the dredging in conventional construction with ecological restoration, soil and water conservation, resource utilization, environment renovation and other environmental protection contents in channel dredging engineering, which, by means of integrated treatment, finally achieves the dual goals of eliminating pollution sources in sediment segments of channels and creating favorable conditions for water ecological restoration. In order to achieve the said effects, in the environmental dredging process, corresponding design modifications shall be made for the dredging equipment, in addition to strictly prepared dredging schemes (usually covering the determination of dredging range, dredging depth, etc.).
Economic analysis of inland waterway system preservation and usage
Published in Zongzhi Li, Transportation Asset Management, 2018
Dredging is the process of excavation from the bed or banks of a river. Since natural rivers generally do not provide a sufficiently passable navigation channel for safe movement of vessels, dredging is necessary not only to help keep the water clean but also to guarantee vessels can pass though safely and efficiently. Dredging is periodically implemented to maintain a clean and safe navigation system. Occasionally, it is required to additionally excavate sediment to accommodate big commercial vessels by enlarging and deepening the navigation channel. According to the USACE, dredging takes place around more than 400 ports and 25000 miles of navigation channels for effective waterway transport operation in the U.S. (USACE, 2015). Also, dredging work has seasonal restrictions because of environmental concerns about the dredging work. Dredging type and size depend on type of sediment, channel alignment, environmental restraints, and site restrictions. The two main types of dredging methods typically used are mechanical dredging and hydraulic dredging.
Water Quality and Water Pollution
Published in Herman Koren, Best Practices for Environmental Health, 2017
Sediment removal from bodies of water can be accomplished through dredging, which may be either done mechanically or hydraulically. Where the sediment does not contain various contaminants, it can be used as clean fill in other areas. Where the sediment is contaminated, it can be contained by a cap of impervious material covered by sand, it can be confined in a special impervious facility, or it can be treated, thereby immobilizing the contaminants, destroying them, or extracting them from the sediment.
Analysis of the suitability of marble waste for beach nourishment
Published in Marine Georesources & Geotechnology, 2023
J. I. Pagán, L. Chiva, A. J. Tenza-Abril, L. Aragonés, I. López
Finally, it is worth noting the economic advantage of using recycled material instead of marine dredged material. The cost of a dredge (including the dredge, floating pipe, auxiliary vessels, and drilling equipment), assuming that the dredging area is less than 1 km from the coast, is approximately 87.5€/m3 (this price does not include the transport of the dredge to the work area). However, according to Hinkel et al. (2018), among others, the existence of sand for dredging on the Spanish coast is very scarce (or almost non-existent) because the continental shelf is very narrow, so the cost would be even higher. On the other hand, the cost of dumping recycled material would be reduced only to the crushing and washing the rock and the subsequent dumping on the beach, which has a cost of about 16.72 €/m3. Therefore, the cost would be about 5 times lower than dredging.
Time-dependent strength behavior of dredged clays at low effective stresses
Published in Marine Georesources & Geotechnology, 2022
Jie Yin, Qing-yuan Wang, Jian-wen Ding, Gui-zhong Xu, Guang-hua Hu
Dredging refers to a requisite ingredient process of excavation of dredged clays from the bottom or sometimes the banks of rivers, lakes, harbors, and other water bodies to maintain the waterway transport. Large volumes of dredged clays must be dredged around the world accordingly. For example, around 270 million m3 dredged clays were dredged each year from U.S (Childs 2015), and more than 100 million m3 were generated annually in China (Zeng, Hong, and Cui 2016; Huang et al. 2017). Therefore, the disposal of dredged clays is the single greatest challenge for most dredging projects (Brils et al. 2014). A possible way is to deal with dredged clay as a reusable material. Existing studies have shown that the beneficial use of dredged clay has great potential in geotechnical applications (e.g., base, subbase, subgrade, structural fills) and can be used as fills in the land reclamations (Limeira, Agullo, and Etxeberria 2012; Yu et al. 2017). In addition, it is a common practice to place dredged clays in confined disposal facilities (CDF), where the dredged deposits always have extremely high-water contents. Moreover, a non-negligible creep strain will generate in the process of natural deposition because of self-weight stress (15 ∼ 25kPa) (Zhang et al. 2007). Therefore, the undrained strength of dredged clays will change over time. It is of great significance to figure out the natural deposition law of dredged clay to improve the storage efficiency of dredged mud in the CDF.
Trace metal leaching from quarry by-product-stabilized marine sediments
Published in Marine Georesources & Geotechnology, 2021
Atul Singh, Margaret Houlihan, Asli Y. Dayioglu, Ahmet H. Aydilek
Dredging operations are necessary to maintain navigation in waterways and access to harbors. Each year, several hundred million tons of materials are dredged from waterways globally (Boutin, 1999, Mattei et al. 2016). These materials, ranging from gravels to clays, can contain a variable amount of organic matter and different types and levels of contaminants (Hamouche and Zentar 2018). Management and storage of dredged materials (DMs) is a worldwide problem, and traditional solutions such as disposing sediments offshore can be constrained by national and international environmental regulations. Alternative solutions, such as land disposal, are costly and require large areas (Grégoire 2004, Rakshith and Singh, 2017). The development of beneficial use strategies for DMs is important in solving these problems.