Effectiveness of novel and traditional treatments on the performance of incinerator bottom ash waste

Management of natural aggregate resources has become one of the most important challenges in construction, especially for high demand applications such as roads. Incinerator bottom ash (IBA), which is produced from burning domestic waste, has been considered a useful solution to the shortage of natural resources. In this research, IBA was mixed with limestone to produce an acceptable blend for use as a road foundation layer. Novel and traditional additives were adopted to improve the mechanical properties of IBA blends. The study focused on the treatment effect of additives on the mechanical characteristics of IBA blends under monotonic and cyclic triaxial stresses. The investigation evaluated fundamental material properties, including resilient modulus, initial Young's modulus and Poisson's ratio. Two nonlinear empirical models were adopted to depict the experimental resilient modulus results of the IBA blends. An approach has been proposed to predict realistic and representative values of resilient modulus for the material. In addition, a new relationship has been established between Young's modulus, resilient modulus and Poisson's ratio. Triaxial test results revealed that additives are more efficient with the control limestone blend than with the IBA blends. Novel additives, such as enzyme I and silica fume, produced a noticeable improvement in IBA properties in comparison to traditional additives.     

Organochlorines in the surface sediments of the Bahiret el Bibane lagoon (Tunisia,Southwestern Mediterranean Sea)

Organochlorines (including organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs)) were analysed in 10 surface sediment samples collected from the Bahiret el Bibane lagoon, which is one of the most productive lagoons and one of the most important active commercial fish traps in the southern Tunisia. The aim was to obtain information concerning the recent deposition of these compounds in this area, together with the levels, the distribution and any potential biological risk. Total concentrations of OCPs and PCBs in the sediments ranged from below the limit of detection (?1 and from 29.5 to 88.2?ng?g^?1?dw, respectively. The spatial distribution of PCBs suggested that the sources of these contaminants are probably located outside the lagoon and are transported by water currents and atmospheric deposition. Compared with some other regions of the world, the Bahiret el Bibane lagoon exhibited low to moderate levels of PCBs and OCPs. According to established sediment quality guidelines, PCBs and Lindane at most of the study sites would be more concerned for the ecotoxicological risk in the Bahiret el Bibane lagoon. The results of this study could provide a useful aid for the sustainable marine management of the region.     

Index methods for the assessment of surface water quality: the case study of Oued Fodda dam,in the Northwest of Algeria

Environment, Development and Sustainability - In this study, the assessment of surface water quality of Oued Fodda dam was carried out by using the physicochemical and organic data recorded during...     

Landscape changes of desertification in arid areas: the case of south-west Algeria

This study aims to monitor the arid Algerian High Plateaus, a key region for pastoral activities which has suffered harsh and widespread degradation from the eighties. This area is not sufficiently known by the international scientific community. For this purpose, we considered phytoecological inventories and thematic maps that have been carried out during 30 years. Available data for the study are vegetation maps derived from aerial photographs (1975-1978) and from satellite imagery (2006). The parameters considered include vegetation, flora, and soil surface properties. The study area is part of the ROSELT/OSS (ROSELT: Réseau d'Observatoires de Surveillance Ecologique à Long Terme (Long Term Ecological Monitoring Observatories Network); OSS: Observatory of the Sahara and the Sahel) network observatory (OSS 2008). To assess land degradation, we used landscape ecology parameters. These include the number and surface area of vegetation units, synthesized by the large patch index and the Shannon landscape diversity index. All parameters reflect an increase in landscape heterogeneity. The largest decline is observed for Stipa tenacissima vegetation units constituting 2/3 of the landscape in 1978 and occupied just 1/10 in 2006. Vegetation units linked to degradation, such those dominated by Salsola vermiculata, inexistent in 1978, now dominate the steppe. Another result of the ongoing landscape degradation on the plateaus between 1975 and 2006 is the decrease of vegetation cover. In 1978, 1/3 of rangelands only had low vegetation covers, inferior to 15%. Presently 9/10 present the same class cover. This can be explained by severe spells of drought combined by an exponential rise of livestock during the last 30 years. This has in turn greatly undermined the fodder potential of the steppe. Results suggest that the "greening-up" described by several authors in the Sahel over the last 40 years is not observed in the Algerian, nor in the North African steppes. On the contrary, the desertification is still ongoing and the threshold of irreversibility seems to be imminent.     

Towards improved socio-economic assessments of ocean acidification’s impacts

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research.     

Thermal,physical, mechanical and microstructural properties of dredged sediment-based ceramic tiles as substituent of kaolin

Environmental Science and Pollution Research - The aim of this study was to recycle dredged sediments as an alternative raw material in the production of ceramic tiles. The effect of the...