Water Resources In Tunisia Research Articles

Assessment of the application of cladode cactus mucilage flocculants for hot chemical degreasing electroplating wastewater treatment and reuse: process efficiency and storage stability.

Pressures related to urban growth and industrial activities exacerbated by climate change had an impact on water resources in Tunisia. The present study examines the application of cladode cactus mucilage (CCM) flocculants for hot alkaline chemical degreasing Zn-electroplating wastewater treatment and reuse (WWTR). The CCM flocculation process was selected through their environmental benefits, economic facilities, sustainable use of the natural biopolymer product, input biopolymers substitution, and on-site treated wastewater (TWW) reuse and recovery. The alum coagulation and CCM flocculation were performed by the jar test series. The suitability of treated wastewater quality (TWWQ) with alum/CCM was also assessed for reuse purpose in terms of corrosion-scaling indices (RSI, LSI, PSI, AI), oxidation-reduction potential (ORP), and microbiological community growth (Bacillus, Pseudomonas, Mesophilic bacteria and yeasts) for 28 days storage at 25 °C. The total alkalinity removal efficiency reached 95.8% with an optimum dosage of alum + CCM for hot alkaline chemical degreasing wastewater bath rinsing. The results showed that the stability of TWWQ has significantly deteriorated during storage leading to aggressive wastewater, pathogen growth, and biological malodor production which make them unsuitable for reuse. Therefore, there is a need for CCM processing alternatives that preserve the physico-chemical and microbial of TWW properties during storage.

Fifty Years of Water Resource Management Policies in Tunisia: From Supply Management to Territorial Equity

Water resources in Tunisia are scarce and unevenly distributed between regions. As well, rainfall varies year-to-year. This study deals with the development of water resource management policies in Tunisia during the last five decades, starting with supply and mobilization management programs that transferred water resources from the interior to the coastal territories where the most important cities are and most economic activity takes place. This policy resulted in the establishment of an interconnected water system that remained in place until the end of the last century. The study also reviews the success of the demand management system the government has been forced by the increase in both urban consumption of water and agricultural needs to adopt. We also review the many challenges that set the current situation apart from previous periods of stress on the system, including high demand, climate change and social movements in the inner cities demanding the right for water, protected in the 2014 Constitution, be respected. The study highlights these challenges and suggests elements for a new resource governance that would draw on the accumulated good governance of the last five decades

The SAFRAN daily gridded precipitation product in Tunisia (1979–2015)

AbstractA new high‐resolution (5 km) gridded daily precipitation dataset for Tunisia between 1979 and 2015 is introduced. This product combines 960 rain gauges with the SAFRAN analysis to produce the precipitation gridded data. A validation approach on two different datasets reveals that the SAFRAN analysis outperforms other standard interpolation methods such as Inverse Distance, Nearest Neighbors, Ordinary Kriging or Residual Kriging with altitude. When compared to EOBS, a widely used gridded dataset over Europe, a strong negative bias in EOBS precipitation is found. However due to the aridity and the low density of rain gauges in south Tunisia, results in this region must be analyzed with care. The SAFRAN product could be useful for various purposes such as climate model evaluation, climate studies, hydrological modelling to support the planning and management of surface water resources in Tunisia.

AN OPTIMAL PRICE FOR SUSTAINABLE IRRIGATED AGRICULTURE IN CENTRAL-EASTERN TUNISIA

Increasing pressures on water resources are causing many countries in Mediterranean to (re)consider various mechanisms to improve water use efficiency for agricultural like Tunisia country. The price mechanism remains the most appropriate instrument to allocate this water resource, but the search for the optimal price of water that reconciles different aspects economic and environmental is the most important issue to rise. In this paper, we will show that the search for a compromise between farm income and water consumption is possible through an optimal price applying both the entropy maximization approach and the multiobjective optimization. The results show that the use of Generalised Maximum Entropy (GME) approach is able to calibrate the model. Once the model is calibrated, a Multi-Objective Programming (MOP) was used to determine the optimal price using the compromise method. This optimal price determined has resulted to a slight economic decline in agricultural income against an immediate environmental gain of water saving. This compromise is a way to ensure the sustainability of irrigated agriculture and the preservation of water resources in Tunisia.

Characterization of Recharge Mechanisms and Sources of Groundwater Salinization in Ras Jbel Coastal Aquifer (Northeast Tunisia) Using Hydrogeochemical Tools, Environmental Isotopes, GIS, and Statistics

Groundwater is among the most available water resources in Tunisia; it is a vital natural resource in arid and semiarid regions. Located in north-eastern Tunisia, the Metline-Ras Jbel-Raf Raf aquifer is a mio-plio-quaternary shallow coastal aquifer, where groundwater is the most important source of water supply. The major ion hydrochemistry and environmental isotope composition (δ18O, δ2H) were investigated to identify the recharge sources and processes that affect the groundwater salinization. The combination of hydrogeochemical, isotopic, statistical, and GIS approaches demonstrates that the salinity and the groundwater composition are largely controlled by the water-rock interaction particularly the dissolution of evaporate minerals and the ion exchange process, the return flow of the irrigation water, agricultural fertilizers, and finally saltwater intrusion which started before 1980 and which is partially mitigated by the artificial recharge since 1993. As for the stable isotope signatures, results showed that groundwater samples lay on and around the local meteoric water line LMWL; hence, this arrangement signifies that the recharge of the Ras Jbel aquifer is ensured by recent recharge from Mediterranean air masses.

Application of multivariate statistical analysis and hydrochemical and isotopic investigations for evaluation of groundwater quality and its suitability for drinking and agriculture purposes: case of Oum Ali-Thelepte aquifer, central Tunisia.

Groundwater plays a dominant role in arid regions; it is among the most available water resources in Tunisia. Located in northwestern Tunisia, Oum Ali-Thelepte is a deep Miocene sedimentary aquifer, where groundwater is the most important source of water supply. The aim of the study is to investigate the hydrochemical processes leading to mineralization and to assess water quality with respect to agriculture and drinking for a better management of groundwater resources. To achieve such objectives, water analysis was carried out on 16 groundwater samples collected during January-February 2014. Stable isotopes and 26 hydrochemical parameters were examined. The interpretation of these analytical data showed that the concentrations of major and trace elements were within the permissible level for human use. The distribution of mineral processes in this aquifer was identified using conventional classification techniques, suggesting that the water facies gradually changes from Ca-HCO3 to Mg-SO4 type and are controlled by water-rock interaction. These results were endorsed using multivariate statistical methods such as principal component analysis and cluster analysis. The sustainability of groundwater for drinking and irrigation was assessed based on the water quality index (WQI) and on Wilcox and Richards's diagrams. This aquifer has been classified as "excellent water" serving good irrigation in the area. As for the stable isotope, the measurements showed that groundwater samples lay between global meteoric water line (GMWL) and LMWL; hence, this arrangement signifies that the recharge of the Oum Ali-Thelepte aquifer is ensured by rainwater infiltration through mountains in the border of the aquifer without evaporation effects.

Desalination and Defluoridation of Tap Water by Electrodialysis

The water resources in Tunisia are very limited and not fairly distributed: 80 % of them are located in the north and only 20 % in the south. In addition, 50 % of them are characterized by a bad quality since they have salinity greater than 1.5 g L−1. The bad quality is not only due to the high salinity, but also to the presence of natural pollutants such as fluoride. In fact, according to physicochemical analyses of samples of tap waters collected by the Regional Service of Environmental Health from different monitoring sites in mining area (south of Tunisia), in February 2014, it was shown that waters were contaminated by fluoride and contained high concentrations of sulphate and chloride anions. Fluoride concentrations varied between 0.8 and 4 mg L−1, and then, greatly exceeded the World Health Organization (WHO) standards in some monitoring sites. In this study, the electrodialysis (ED) technique was applied to remove fluoride from these waters. Experiments were carried out using a pilot unit as a conventional ED in batch recirculation mode. It was shown that ED is an efficient technique to remove fluoride and to reduce salinity of water. Removal rate of fluoride tended to 92 % and the concentrations of different species in the treated water were below the amounts recommended by WHO for drinking water. Considering the effect of chloride and sulphate on fluoride removal through the anion exchange membrane, the performance of two types of ion exchange membrane (PC Cell and Neosepta) was compared. Experiments were carried out with synthetic solutions containing 0.0357 mol L−1 of NaHCO3 doped with 15 mg L−1 of fluoride. Sodium hydrogenocarbonate was replaced by sodium chloride or sodium sulphate at different values of molar ratio in order to maintain the initial ionic strength of the solution constant at 0.0357 mol L−1. It was shown that fluoride removal was influenced by chloride ions but not by sulphate ones.

AquaFej: a simulation game for planning water management - an experiment in central Tunisia

Until the 2000s, water resources in Tunisia were managed solely by government bodies without any consultation with water users. At the local level, Commissariats Regionaux de Developpement Agricole [Regional Agricultural Development Committees (CRDAs)], which represented the government bodies, managed water resources. The Tunisian Government then decided to involve farmers in the local management of water resources by creating Agricultural Development Associations (GDAs). Water resource management by CRDAs must now take into account water demand from farmers belonging to GDAs and, in return, farmers must acknowledge water scarcity and accept the need for resource-sharing. How can CRDAs and GDAs work towards cooperative water management? In this paper, we present a simulation game requested by officials at the Kairouan CRDA in order to develop cooperative management of the water resources in a typical small watershed in central Tunisia. Our aim was to use the game to increase both farmers’ awareness of water resource-sharing, scarcity, and the impact of overexploitation, and CRDA officials’ awareness of different uses that determine water demands. The game is based on a hydrological model of the watershed and an agro-economic model of farming systems that use water resources for irrigation.

EFFICIENT DESIGN OF A PHOTOVOLTAIC WATER PUMPING AND TREATMENT SYSTEM

Through the world, the exploitation of solar energies knew a strong growth these last years. It is interesting to exploit them on the place of consumption, by directly transforming into heat, or in electricity according to needs and especially in remote areas where power from utility is not available or is too costly to install. The use of photovoltaic sources in water pumping and treatment domain is one of the most important renewable energy applications. Having an arid to a semi-arid climate, Tunisia receives low quantities of rain. Consequently, the available water resources in the country are rather modest in terms of both quantity and quality. 97% of water resources in Tunisia are of brackish water, particularly in the south parts of the country. Originate from ground water resources and surface, these waters are unsuitable for drinking or irrigation, because of the high salinity and biological contagion in sensitive (perceptible) germs. The goal of this study is to direct the applied researches to the applications of coupling the photovoltaic energy, which is available in the south of the country and water domain (pumping, desalting and disinfecting). We present in this study some of pilot units coupled to photovoltaic sources and we propose a global system which gathers the water pumping, desalting and disinfecting operations. Some experimental and numerical results have been carried out to show the efficiency of the use of this system. The conception, the realization and the exploitation of this autonomous system will be the suitable solution for providing fresh water to a number of rural regions where important quantities of water are needed to either, the drinking and irrigation, in Tunisia and in the Mediterranean basin in general.

Using GIS for the Comparison of Intrinsic Parametric Methods Assessment of Groundwater Vulnerability to Pollution in Scenarios of Semi Arid Climate. The Case of Foussana Groundwater in the Central of Tunisia

Groundwater vulnerability maps have become a standard tool for protecting groundwater resources from pollution. They are especially valuable in the decision making process related to land use planning. In fact, mangers have mostly little experience and expertise at hand to decide which land uses and activities are to be allowed in certain areas without causing a negative impact on the quality of groundwater. Hence, numerical modeling of various hydrological parameters and assessment of vulnerability to potential pollution of water resources in Tunisia has been the subject of several studies since 1980. These water resources are becoming increasingly scarce, overexploited, poorly distributed and most especially polluted including Mioplio quaternary Foussana Aquifer located in the western of the Kasserine area in the central Tunisia, which is considered as an economic resource priority because it is used in irrigation and domestic consumption. The area of the aquifer is essentially occupied by agricultural areas characterized by an important use of chemical fertilizers which are in addition to the discharge of industrial zones, an ongoing risk to the groundwater quality; this prompts us to a hydrological study and vulnerability late attributed to improve management of water resources in the study area. In this context, the use of GIS and remote sensing seems to be an effective tool the aquifer vulnerability evaluation, by applying various methods: standard DRASTIC, GOD, SINTACS and SI. The application of these methods shows that the most vulnerable zone is the southern part of the Foussana aquifer. So these maps could serve as a scientific basis for sustainable land use planning and groundwater management in the study area.

Groundwater mineralisation processes in Mediterranean semi‐arid systems (Cap‐Bon, North east of Tunisia): hydrogeological and geochemical approaches

AbstractThe groundwater of the Korba plain represents major water resources in Tunisia. The Plio‐Quaternary unconfined aquifer of the Cap‐Bon (north‐east Tunisia) is subject to the intensive agricultural activities and high groundwater pumping rates due to the increasing of the groundwater extraction. The degradation of the groundwater quality is characterized by the salinization phenomena. Groundwater were sampled and analysed for physic‐chemical parameters: Ca2+, Mg2+, Na+, K+, Cl‐, SO42‐, HCO3‐, NO3‐, pH, electrical conductivity (EC), and the temperature (T°). The hydrochemical analysis is coupled with the calculation of the saturation indexes (SI gypsum, SI halite, SI calcite and SI dolomite), ionic derivation and with the ion correlations compared to chloride concentrations: Na+/ Cl‐, Ca2+/ Cl‐ and Mg2+/ Cl‐ ratios. Seawater fractions in the groundwater were calculated using the chloride concentration. Those processes can be used as indicators of seawater intrusion progression. EC methods were also conducted to obtain new informations on the spatial scales and dynamics of the fresh water–seawater interface of coastal groundwater exchange. The mixing zone between freshwater and saltwater was clearly observed from the EC profile in the investigated area where a strong increase in EC with depth was observed, corresponding to the freshwater and saltwater interface. Results of hydrochemical study revealed the presence of direct cation exchange linked to seawater intrusion and dissolution processes associated with cations exchange. These results, together with EC investigation, indicated that the groundwater is affected by seawater intrusion and is still major actor as a source of salinization of the groundwater in Korba coastal plain. Further isotopic and hydrological investigations will be necessary to identify and more understood the underlying mechanisms. Copyright © 2012 John Wiley & Sons, Ltd.

Impact of Treated Wastewater Reuse on Agriculture and Aquifer Recharge in a Coastal Area: Korba Case Study

Treated wastewater (TWW) reuse has increasingly been integrated in the planning and development of water resources in Tunisia. The present study aimed the evaluation of the environmental and health impact that would have the reuse of TWW for crops direct irrigation or for the recharge of the local aquifer in Korba (Tunisia). For this purpose water analyses were carried on the TWW intended for the aquifer recharge and on underground water of this area. As for underground water before recharge, no contamination by organic matter or heavy metals is shown but high salinity, nitrate, potassium and chloride concentrations are detected. The bacteriological analyses show the occurrence of faecal streptococcus, thermo-tolerant coliforms, total coliforms and E coli, but absence of salmonella. These results indicate that this water is not suitable for irrigation worse still for drinking purpose. The monitoring of TWW pollutants has demonstrated that oxygen demands (COD and BOD) do not exceed the Tunisian standards for TWW used in agriculture (NT 106.03) except for August when samples reach high values (COD = 139 mg O2 L − 1, BOD = 34). It is also the case for temperature, electrical conductivity (EC), salinity and pH. Heavy metal concentrations are under the detection limit. The determination of nutrients shows relatively low concentrations of nitrates, nitrites and orthophosphate (the maxima in mg L − 1 are respectively 6.6, 5.6 and 0.92) whereas the potassium levels are high (up to 48.8 mg L − 1) and the ammonia levels very high, reaching 60.6 mg L − 1. As for bacteriological pollution, while no salmonella and intestinal nematods are detected, high concentrations of total coliforms, thermo-tolerant coliforms, faecal streptococci and E. coli are analysed. Consequently, the better use of TWW in this region would be the use of infiltration basins for the recharge of the deteriorated aquifer by TWW. It would give the opportunity to better the quality of the TWW reaching the groundwater by an additional treatment for bacteriological and suspended solid (TSS) contaminants while being an alternative water for the aquifer recharge and a coastal barrier against seawater intrusion.

Water resources and management in Tunisia

This paper focuses on the work done through the INRGREF to collect and analyse available information on water resources in Tunisia. It presents the quantity and quality of surface and groundwater resources data. Water resources in Tunisia are characterised by scarcity and a pronounced irregularity. Tunisia has been able to develop a complex and diverse water infrastructure allowing the country to mobilise and exploit available water resources. This paper is intended to provide an overview of the current water situation in Tunisia by presenting its water potential with a focus on its regime and spatial variability, water demand trends for the different economic sectors, the choices made to manage the water balance deficits, and the various problems and challenges faced in managing this resource.