• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.63-69
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• 2012

Sediment has been increasingly acknowledged as a carrier in water system and an available contamination. For this reason, dredging of sediment in reservoir to remediate water quality and secure storage capacity is conducted annually. However, disposal of numerous dredged sediment is necessary as a secondary problem. Currently, in Korea, dredged sediment is classified as waste to be reclamated or recycled into sandy soil, however, they are still in trouble because of spacial and environmental problem. Therefore, rather than simple disposal or reuse into sandy soil, it is necessary to research on method to manage main cause of pollution and increase the value as a resource. In this study, we intend to develop a recycle technology for numerous dredged sediment produced by dredging in deteriorated reservoirs using solidificator (stabilizer). To achieve this, we will consider utilization of dredged sediment and evaluation of use possibility as natural recycle by analysis the characteristics of soil-solidificator mixture in terms of physicochemical properties and the mixing ratio between sediment and solidificator.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1060-1067
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• 2006

Sandy soils are generally used as a capping material to reduce the pollutants transport from the contaminated dredged sediment. However, dredged material capping is not widely used because regulatory agencies are concerned about the potential for contaminants migration through the cap. Movement of contaminated pore water from sediment into cap is mainly related to sediment consolidation during and after cap placement. To evaluate the significance of consolidation induced transport of contaminants from sediment into cap, research centrifuge tests were conducted. Centrifuge test results illustrate that advection and dispersion are the dominant contaminants transport processes and that capping reduces the potential of contaminant migration from the dredged sediment effectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.54-57
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• 2002

Pretreatment technologies are defined as technologies that prepare or condition dredged material for subsequent, more rigorous treatment processes. The objectives of this study are to test the feasibility of treating dredged sediment using pretreatment process(hydrocyclone, sedimentation basin, and flotation), and to estimate design parameters for a pilot-plant design. The final goal of the project is to recycle the dredged sediment that is otherwise reused as construction materials.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.63-69
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• 2008

As a basic study on the creation of artificial tidal flats using dredged sediments, the pilot-scale artificial tidal flats with 4 different mixing ratio of ocean dredged sediment were constructed in Nakdong river estuary. The phragmites australis was transplanted from the adjacent phragmites australis community after construction, and then the survival and growth rate of the planted phragmites australis were measured. Also the changes of soil chemical oxygen demand (COD), ignition loss (IL), and the heterotrophic microbial numbers were monitored. The survival rate of the planted phragmites australis decreased as the mixing ratio of dredged sediment increased but there was little difference of length and diameter of the shoots. 30% of COD and 9% of IL in the tidal flat with 100% dredged sediment decreased after 202 day, however, fluctuations of COD and IL concentrations were also observed possibly due to the open system. It was suggested that the construction of tidal flats using ocean dredged sediment and biological remediation of contaminated ocean dredged sediment can be possible considering the growth rate of transplanted phragmites australis, decrease of organic matter and increased heterotrophic microbial number in the pilot plant with 100% dredged sediment. However, the continuous monitoring on the vegetation and various environmental factors in the artificial tidal flat should be necessary to evaluate the success of creation of artificial flats using dredged sediments.

• Advances in concrete construction
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• v.4 no.1
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• pp.15-26
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• 2016

In Algeria, wastes are often stored in such conditions that do not meet standards. Today and more than ever, we really must implement an environmentally management of wastes. Recovery of waste in Algeria has a considerable delay due to the absence of a policy favorable to the development of waste management. But many researchers have shown the possibility to reuse dredged sediments in road construction. Through Europe, recent research works have been already performed on dam sediments. Present study fits into the context of the valorization of dredged sediments from Fergoug dam. They are found in considerable quantities and mainly composed of mineral phases, organic matters and water. The reservoir sedimentation poses problems for the environment and water storage, dredging becomes necessary. Civil engineering is a common way of recycling for such materials. Dredged sediments have not the required mechanical characteristics recommended by the standards as GTR guide (LCPC-SETRA 1992). So as to obtain mechanical performance, dredged sediment can be treated with cement, lime, or replaced materials like quarry sand. An experimental study has been conducted to determine physical and mechanical characteristics of sediments dredged from dam. Then different mixtures of sediment and/or quarry sand with hydraulic binders are proposed for improving the grain size distribution of the mixes. Finally, according these mixtures, different formulations have been tested as alternative materials with dredged sediments.

• Journal of Environmental Impact Assessment
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• v.24 no.5
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• pp.444-455
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• 2015

In relation to the utilization and disposal of dredged sediment caused by coastal dredging project, we diagnosed the status of legal standard and system, and proposed the improvement plan. Dredging costal sediment distinguished the usage and the disposal by the Standard for the Beneficial Usage of Dredged Sediment. The site where disposal has been completed could be used as a site for developmental project. In case of the usage of dredged sediment for reclamation, we found that the adaptation of the Standard for Beneficial Usage of Dredged Sediment is appropriate for reclamation considering the characteristic of soil, the differences of variables, and the distinction of standard analysis methods. The current the Standard for Beneficial Usage of Dredged Sediment requires the improvement with the usage of dredging coastal sediment in the following. First, the Standard needs to include the standard of the discrimination for reclamation. Second, the current Standard is necessary to be divided by two levels, it needs to be mitigated considering human health risk. Third, it is necessary to consider both the marine environmental impact assessment and mitigation plan near coastal dredging area.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.619-626
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• 2014

In this paper, it was constructed the halophyte Mesocosm experimental which was used tidal flat and dredged sediment as a substrate material. Depending on the vegetation and substrate material of Mesocosm, Mesocosm A(tidal flat sediment + Salicornia herbacea), Mesocosm B (only dredged sediment), Mesocosm C(dredged sediment + Salicornia herbacea). Monitoring was carried out of Warter quality factots(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P), water temperature, salinity), Sediment factors(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P)) and growth of Salricornia herbacea. Habitat Stability Index of vegetation was calculating by using the monitoring results. HSI of Mesocosm C was calculated from 0.87 to 0.95 as compared to the relatively high HSI in Mesocosm A, it was evaluated to be able to be used in the restoration and construction of the coastal salt marsh with dredged sediment.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.53-60
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• 2010

In the present study, experiments have been performed to investigate the possibility of removing Cochlodinium polykrikoides using the dredged sediment from a coastal fishery and then to derive the optimal conditions; the amount and particle size of dredged sediment besprinkled into water, the thermal treatment, the types and amounts of additives, and the depth profile of Cochlodinium polykrikoides. Results showed that the optimal amount of dredged sediment besprinkled into water was 6~10 g/L, and the removal efficiency of Cochlodinium polykrikoides after the reaction time for 60 min was 73~93%. Note that, in the real sea water, it is necessary to besprinkle 6~10 $kg/m^3$ of dry dredged sediment on a unit area (1 $m^2$). With decreasing particle size, Cochlodinium polykrikoides could be more efficiently removed. The removal efficiency was 93% with the dredged sediment smaller than 100 ${\mu}m$, whereas it was 51% with that of 100 ${\mu}m$ ${\mu}m$. Since most of dredged sediment (over 90%) was smaller than 100 ${\mu}m$, high efficiency could be obtained by besprinkling only the dredged sediment without pre-treatment. CaO was found to be an effective additive in promoting the removal efficiency (up to 99%). The optimal amount of additive was 5~10%, however, it was necessary to use as small amount of an additive as possible in order to avoid the sharp increase in pH. The removal efficiency increased with increasing depth profile of Cochlodinium polykrikoides. The removal efficiency was 83% at 5 cm depth, whereas it was 93% at 50 cm depth. In the sea water, red tide occurred within 3 m depth, and furthermore most Cochlodinium polykrikoides existed within 1 m depth. It was, therefore, expected that higher removal efficiency of Cochlodinium polykrikoides could be obtained when the dredged sediment was besprinkled into the sea water. The removal efficiency of Cochlodinium polykrikoides was up to 93% when the dredged sediment (<100 ${\mu}m$) was besprinkled into water at the ratio of 10 g/L. This result was comparable to that obtained with loess (90~97%). All the results in the present study indicated that the dredged sediment from a coastal fishery could be successfully used as a substitute of loess for removing the red tide alga.

• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.57-66
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• 2013

Although the quantity of dredged soils has increased owing to recent new harbor construction, sea course management, polluted sediment dredging, and four-river project, the reuse or recycling of those dredged soils has not done properly in Korea. To develop measures to utilize them in various ways for reuse or recycling, the biophysicochemical properties of dredged soils and sediment were assessed in this study. Samples were classified according to their sources-river and sea-by location, and as dredged soil and sediment depending on storage time. The results showed that dredged materials from the sea have high clay content and can be used for making bricks, tiles, and lightweight backfill materials, while dredged materials from the river have high sand content and can be used in sand aggregates. Separation procedures, depending on the intended application, should be carried out because all dredged materials are poorly sorted. All dredged soils and sediments have high salinity, and hence, salts should be removed before use for cultivation. Since dredged materials from the sea have adequate concentrations of nutrients, except phosphate, they can be used for creating and restoring coastal habitats without carrying out any additional removal processes. The high overall microbial activities in dredged materials from the river suggested that active degradation of organic matter, circulation of nutrients, and provision of nutrients may occur if these dredged materials are used for cultivation purpose.

• Journal of Environmental Science International
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• v.17 no.1
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• pp.29-36
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• 2008

A large amount of $2.1{\times}10^6m^3$ of polluted sediment was dredged from the Masan Bay and deposited in Gapo confined area, Masan, Korea. The six representative sediments were obtained and analyzed for issue components. The data was discussed with the species of benthos and their distribution. It was judged that toxicological effects of sediment analyzed ranged from ERL to ERM with copper and zinc, and ERL with cadmium, chrome, lead and nickel by the Adverse Biological Effects. The dredging index (DI) of sediments stabilized for 10 years since dumping the confined site was calculated and compared with the DI values of dredged sediment itself. DI values decreased from 0.67 to $0.07{\sim}0.18$, which reflects DI value less than 0.2 is good for benthos in the sediment by the natural recovery of dredged materials. The ecological recovery was confirmed in this confined area as a habitat of benthic organisms.