Irrigation And Risk Of Saline Pollution. Example: Groundwater Of Annaba Plain (North East Of Algeria)

In the Annaba plain (Northeast of Algeria), the anthropogenic activities have imposed serious unfavorable impacts on hydraulic, hydrochemical and biological balances that influence the socio-economic future of this area. A hydrochemical analysis was performed in 29 wells distributed over the whole of the plain region during the period of high water (December 2013) to assess the quality of groundwater for its suitability for irrigation. Several parameters were analyzed such as pH, TDS, Ca +2, Mg +2, Na+ , K+ , HCO3 - , Cl- and SO4 - . Analysis of results suggests that groundwater in the study area has the same qualities; however the observed degradation reflects a change in the water quality, and the SAR values vary from 0.08 to 16 with an average of 1.3. The US salinity laboratory, Wilcox, and percentage Na+ it suggest that the majority of groundwater samples are not good for irrigation

Using GIS-Based Tools for the Optimization of Solid Waste Collection and Transport: Case Study of Sfax City, Tunisia

Expenditure for waste collection and transport in Tunisia constitutes 75–100% of the total solid waste management budget. In this study, optimized scenarios were developed using ArcGIS Network Analyst tool in order to improve the efficiency of waste collection and transportation in the district Cité El Habib of Sfax city, Tunisia. Geographic Information System (GIS) was created based on data collection and GPS tracking (collection route/bins position). The actual state (Scenario S0) was evaluated, and by modifying its particular parameters, other scenarios were generated and analyzed to identify optimal routes: S1, route optimized with the same working resources (change of stops sequencing only); S2, route optimized with change of vehicles; and S3, route optimized with change of collection method (vehicles and reallocation of bins). The results showed that the three scenarios guarantee savings compared to S0 in terms of collection time (14%, 57%, and 57% for S1, S2, and S3, resp.) and distance (13.5%, 13.5%, and 40.5% for S1, S2, and S3, resp.). Thus, a direct impact on fuel consumption can be expected with savings of 16%, 20%, and 48% for S1, S2, and S3, respectively, without mentioning the additional benefits related to CO2 emissions, hours of work, vehicles wear/maintenance, and so forth

Chemical activation effect on the mechanical response of mortars based on dune sand

The main qualities sought for a mortar are usually; the high compactness, good sealing or impermeability, better mechanical strength and long-term durability. The different methods of accelerating setting and hardening of the mortar as well as the desired characteristics are of great importance with regard to the use of mortars and their different applications in civil engineering. This work is a contribution to improving the properties of mortars at fresh and hardened state by different activation techniques in particular chemical alkaline activators method. The properties of chemically activated mortars using alkaline solutions (KOH and NaOH) at dosages of 0, 2 and 4% was investigated in this experimental program using a based cement matrix with dune sand and blended cement type CEM II/ B grade 42. The results obtained showed the beneficial effect of the chemical activation modes mainly, an improvement of the mechanical response (compressive strength) at young age and in the long term

Étude expérimentale de la biorestauration des sols souillés par les hydrocarbures

The biodegradation is considered an efficient and economic tool in resolving hydrocarbons soil contamination problems. The feasibility study of this technique for four soil types, which are particularly exposed to this risk, is the main object of this work. It is shown from the experimental study that many factors affects this phenomenon. The hydrocarbons biodegradation rate is related to the nature of the solid matrix, the hydrocarbon type, initial concentration of the contaminated soil and the availability of nutriments.Thus, for the same soil type, the petrol is the most biodegradable hydrocarbon with a rate of 50 %, than comes the diesel oil with 33 % and the fuel with a rate of 17.6 % relatively to the non evaporated hydrocarbon fraction. The clayey soils are the most unfavourable for the biological remedial of hydrocarbons pollution, the least biodegradation rates are recorded in these soils.The control of bacteria populations growth in time has permitted to define an optimal time period for ending a biological treatment plan of an hydrocarbon contaminated soil.La biodégradation peut être considérée comme une méthode efficace et économique face aux problèmes de contamination des sols par les hydrocarbures. Dans ce travail il s’agit d’étudier la faisabilité de cette technique pour quatre sols, qui se trouvent particulièrement touchés par ce problème, vis-à-vis de trois hydrocarbures largement utilisés. L’étude expérimentale de la biodégradation des hydrocarbures dans le sol a montré que plusieurs facteurs interviennent dans ce phénomène. Le taux de biodégradation de ces composés est lié simultanément au type d’hydrocarbure, à la nature de la matrice solide, à la concentration initiale en hydrocarbures du sol contaminé et enfin à la disponibilité des substances organiques dans le milieu contaminé.Ainsi, pour un même type de sol, l’essence est la famille d’hydrocarbures la plus biodégradable avec un taux de biodégradation de 50 % suivie par le gazole (33 %) et le fioul (17,6 %) par rapport à la masse d’hydrocarbures non évaporés. Les sols argileux sont les plus défavorables pour le traitement d’une pollution pétrolière par biodégradation. Les taux de biodégradation les plus faibles ont été enregistrés sur ces sols.Le suivi du développement des populations bactériennes en fonction du temps a permis de définir une période de temps optimale pour achever un traitement par biodégradation d’un sol contaminé par des hydrocarbures

Impact of climate change and anthropogenic pressure on the groundwater resources in arid environment

Climate and anthropogenic changes are expected to reduce renewable groundwater resources and to increase the risks of water scarcity, particularly in arid regions. Understanding current and future risks of water scarcity is vital to make the right water management decision at the right time. This study aims to analyze the impact of both human and climate pressures on groundwater availability in an arid environment: the Regueb basin in Central Tunisia. An integrated approach was used and applied at a monthly time step over a reference period (1976–2005) and a future period (2036–2065). Groundwater resources were assessed using hydrogeological modeling. Irrigation water withdrawals were evaluated based on remote sensing and the CropWat model. Urban water use was estimated from population growth and specific monthly water consumption data. The resulting values were used to compute two indicators (water stress index, groundwater balance) to evaluate water scarcity risks at the 2050 horizon. To assess current and future climate forcing on water resources, three climate scenarios were generated based on simulations from Coupled Model Intercomparison Project Phase 5 (CMIP5) data. A business-as-usual and an adaptation scenario (optimal cropping scenario) were performed by varying the surface areas and the crops grown in the irrigated area. Results show that the average annual water use will increase by 3.8 to 16.4% under climate change only, whereas it will increase by 100% under the business-as-usual scenario. Under the optimal cropping scenario, total water demand will increase by 50%. Water stress index indicates that under the climate change only scenario, water demand should be satisfied by the 2050 horizon, while under the other two scenarios, severe water stress will occur by 2050. The developed framework in this paper aims to fit in arid and semiarid regions in order to evaluate groundwater stress and to assess the efficiency of adaptation strategies. It results in two major recommendations regarding changes in land use and the improvement of groundwater monitoring

Potential for fresh submarine groundwater occurrence in an arid Mediterranean region, case of Gulf of Gabes, Tunisia

Peer reviewedPostprin

Valorization of harbor dredged sediment activated with blast furnace slag in road layers

International audienceThe valorization solutions for dredged sediment have been the subject of a great number of investigations over the previous decades. In the current present study, treatment of polluted dredged sediment fom the commercial port of Sfax, Tunisia, is proposed. An industrial byproduct (blast furnace slag) was used to bind raw sediment for a reuse in road engineering.Following standards of this field, the raw sediment first was identified and classified according to the French technical guidance. Then an environmental assessment was applied due to the presence of heavy metals. The concentrations were measured on the raw sediment particles so as to control the binding effect on heavy metals. Sediment mixtures consisted of a mix of sand and a blast furnace slag activated with quicklime. Different mixtures were tested and some were proposed for sub-layer applications. The Sfax commercial port raw sediment is considered as a sandy loam with a very low fraction of clay. The measured concentrations of heavy metals exceed the recommended thresholds for cadmium, copper, lead, and zinc. These can induce hazardous effects in the case of their dumping into the sea. On the other hand, the concentrations of the detected elements after leaching tests run on raw sediment samples are very low compared to the thresholds; such results highlight a possible recycling of the raw sediment in subgrade layers without any negative impact. Suitable formulations were deduced for road engineering tests relying on the ratio the California Bearing Ratio index and the immediate bearing index. If the obtained ratio exceeds one, the treated sediment can be recycled and used in road layers