https://hal.archives-ouvertes.fr/hal-01308108/document

Feasibility of the reuse of total and processed contaminated marine sediments as fine aggregates in cemented mortars

Sediments are the particulate matter that are transported by the flow of water and eventually get deposited at the bottom of water bodies, such as oceans, rivers, lagoons, and so forth. The deposition of these materials due to continued intervention of natural as well as anthropogenic activities is a serious concern as the storage capacity (or health) of the system is reduced or otherwise affected. Keeping in view the emerging challenges associated with proper disposal and subsequent utilization of sediments, as a manmade resource, their extraction from such locations becomes necessary. Hence, it is essential to characterize the sediments in order to devise strategies to exploit them as a manmade resource in the best possible manner. With this in view, this article highlights the importance of different attributes and aspects of the sediments (viz., physical, chemical, morphological, geotechnical, toxicological, and microbial characteristics) deposited in the water bodies that will help in assessing their...

Characterization of Sediments for Sustainable Development: State of the Art

In order to better understand the mechanisms of cement treatment on the expansive clay, this study presents a long-term study on the micro-structure evolution of the cement-treated highly expansive clay (Handan clay) over a curing period of one and an half years through scanning electronic microscope (SEM) tests and X-ray diffraction analyses. A series of unconfined compression tests were also conducted on cement-modified clay. SEM testing results revealed the microstructure change and cement hydration process during cement treatment of the highly expansive clay. Cement added to the expansive clay generally experiences a hydration, initial setting to form a gel membrane, final setting to form a semi-solid gel and eventual solidification process. The microstructure of the highly expansive clay goes through a series of changes, from a dispersive structure before adding cement, to a flocculated and agglomerated structure after adding cement, further becoming a semi-solid and chained net structure due to the ...

A long-term investigation on microstructure of cement-stabilized handan clay

Purpose: Dredging of sediments, a requirement for harbor maintenance, removes millions of tons of mineral wastes, contaminated at varying degrees with trace metals, from the water. In previous investigations, Cu and Zn have been identified as highly concentrated trace metals associated to sulfides, mineral phases sensitive to oxidation. In order to ensure their sustainable management, the solidification/stabilization (S/S) and/or the valorization of contaminated sediments as secondary raw materials is a way to be promoted. Indeed, their reuse as a substitute of sand in cemented mortar formulation would allow combining both treatment and valorization of such wastes. Methods: In the present study, the environmental assessment of mortars formulated with raw and weathered marine sediments (in particular contaminated with Cu, Pb and Zn), compared to sand reference mortars, was conducted through two kinetic leaching tests: weathering cell tests (WCTs), in which mortars were crushed and leached twice a week, and a tank monolith leaching test (MLT), in which leaching was performed on monolithic mortars with increasing leachate renewal time. Results: In both leaching tests, calcium and sulfur were released continuously from sediment mortars, showing the oxidation-neutralization processes of sulfides and carbonates. In the MLT, Cu was released by sediment mortars through diffusion, particularly by weathered mortars, at low concentrations during 60 days of the test duration. With the more aggressive WCT, Cu concentrations were higher at the beginning but became negligible after 7 days of testing. Pb was released through diffusion mechanisms until depletion in both tests, whereas Zn was particularly well immobilized in the cemented matrices. Conclusions: The S/S process applied using hydraulic binders proved to be efficient in the stabilization of Cu, Pb, and Zn highly presents in studied sediments, and further valorization in civilian engineering applications could be considered.

Environmental evaluation of dredged sediment submitted to a solidification stabilization process using hydraulic binders

The incessant growth in urbanization, and the population explosion associated with it, has resulted in an increased discharge in sewage disposal lagoons and has led to their overloading. This results in the improper functioning of these lagoons, which greatly affects the treatment of sludge and wastewater. The influents, which carry along with them a huge load of substance, referred to as socioeconomically generated sediments (SeGSs), substantially reduce the capacity of the lagoons and the retention time of the sewage water and sludge. This situation poses a major challenge to municipal engineers and town planners, and to overcome it, either periodic or once-per-lifetime desiltation of these lagoons is warranted. However, in present-day megacities, there are several concerns associated with the desiltation process, viz., selection of the most economical and efficient technique, the availability of dumping ground(s), and transportation of the SeGSs to these dumping grounds. This is where utilization of SeGSs as a manmade resource could be a good initiative towards sustainable development. However, this endeavor entails a holistic understanding of the SeGSs by conducting detailed investigations to characterize them based on their physical, chemical, morphological, and microbial attributes before postulating a strategy for their sustainable utilization. With this in view, extensive sampling of the SeGSs from sewage disposal lagoons located in the western part of India was conducted followed by their very comprehensive characterization. Details of the methodologies adopted for this exercise were presented in this manuscript, and recommendations were made to utilize SeGSs for sustainable development in the most efficient manner.

Characterization of Sediments From the Sewage Disposal Lagoons for Sustainable Development

Morocco has valuable assets in marine seaboards and resources. The Mediterranean coasts do more than attracting tourists. That is why it is imperative to reconcile economic development with the quality of the environment. The industrial area in Tangier (Morocco), situated in the south-east area of the city, is a primary source of sediment pollution in the canal which runs through the area and discharges into the sea. This paper studies the contaminated and untreated sediments from that canal. A physical, chemical, mineral and environmental characterization was made to evaluate its possible use as sand for mortar. The replacement of sand by sediment indeed reduces the mechanical strengths. The chemical analysis of leachates after leaching test yet show a certain stabilization of pollutants, specially heavy metals in the cementitious matrix.

Stabilization of contaminated canal sediments

Application of Life Cycle Assessment (LCA) to Urban Sludge Treatment Techniques for a Comparison Study: A Review

Integration of an Industrial Waste in the Manufacturing of a Cementitious Construction Material

Financial and Economic Assessment of Rehabilitation of a Drinking Water Supply: Case Study

Agroforestry is an example of a triple-win practice as it can support food security, mitigate climate change and contribute to adaptation to these changes. As such, agroforestry is considered a climate-smart practice. This Study was conducted to analyze the effect of distance from the olive row on soil fertility parameters in intercropping system at two different soil types (Fersiallitic and vertisols) in Saiss region of Morocco. To carry out this work the studies were done in two rainfed olive orchards. The plant material used in this study is local species of legumes (fababean, chickpea and lentil) cultivated in intercropping systems based on olive trees. The experimental design adopted was a randomized complete block. The factor studied is the distance from the olive rows. After harvesting annual crops, soil samples were taken from the 0–30 cm layer at different distances from tree row. These samples were subjected to chemical analyzes to determine their fertility levels. Our results demonstrate that the distance from the olive row had different effects on soil parameters measured in each plot of the intercropping to the olive tree for the two soils type studied. For chickpea-olive intercropping systems, the soil nitrate content is the only parameter that was affected by the distance from the olive row in Fersiallitic soil. In the fababean-olive intercropping systems, the distance from the olive row affected the soil organic matter content in Fersiallitic soil. For lentil-olive intercropping systems, soil fertility parameters did not differ significantly by the distance from the olive row. In Vertisols, the distance from the olive row had no effect on any soil parameter measured for each plot of intercropping to the olive tree. 

Laïla Ben Allal

Papers

Stabilization of contaminated canal sediments

Application of Life Cycle Assessment (LCA) to Urban Sludge Treatment Techniques for a Comparison Study: A Review

Integration of an Industrial Waste in the Manufacturing of a Cementitious Construction Material

Financial and Economic Assessment of Rehabilitation of a Drinking Water Supply: Case Study

Soil Fertility Management on Smart Production System Resilient to Climate Change