LARHYSS Journal

10

Authors: KAHOUL M., TOUHAMI M.

Chemical pollution of water becomes today a public health concern. Indeed, many water-borne diseases are due to the presence of natural or synthetic chemicals, and for this, the use of water or for food hygiene requires excellent physico-chemical and microbiological quality. To contribute to quality control of water intended for consumption in the city of Annaba (Algeria), our study focused on the evaluation of the physico-chemical quality of water in this region which has very significant water resources both surface and underground. The analyzes were performed according to standard methods on several samples at three sites in the city and involved temperature (T°), pH, electrical conductivity (EC), total hardness(TH), nitrate (NO3), calcium (Ca) and chloride (Cl-). By comparing the obtained results to algerian and international standards, it appears that most of the physicochemical parameters are normal and thus the quality of controlled water is relatively well.

11

Authors: SAADI S., KHATTACH D., EL KHARMOUZ M.

The urban waste produced by Oujda city, mixed with solid waste of industrial and hospital origin, was disposed since 1990 until 2005 on an open-air landfill situated approximately 7 km southeast of the city center. The groundwater circulates deeply (25-30 m) in grounds post-Miocene on an impermeable substratum formed by the marls of Miocene. The ground is calcimagnesic not very deep, with a more or less important layer of silts and clays. To evaluate the impact of the leachate resulting from this landfill on groundwater quality, samples of leachate and groundwater were taken during the year 2005 (five samples of leachate inside the landfill) (three groundwater samples were taken from three wells located near the landfill) and two profiles of recognition by electric imaging were realized according to the device pole–pole two dimensional (2D) inside the landfill. The analyses of the sample leachate revealed strong content of Chemical oxygen demand (COD max = 30760 mg/l), biodegradable organic matter (DBO5 max = 653.3 mg/l) and of mineral matter (conductivity: max = 63.73 mS/cm). The analysis of groundwater revealed that NO3- presents an average concentration higher than 50 mg/l (Standard suggested by WHO). The concentration of chloride exceeds 1450mg/l (Standard suggested by WHO is 600 mg/l for fresh waters). Concerning heavy metals, the concentrations of Iron, Zn and Ni largely exceed the French values standards fixed for groundwater, while the Cd contents are lower than this standard. The results of the geo-¬¬¬electric prospecting showed that the very low electric resistivities (5 ohm.m), were observed in the inside and in the direct approval of the landfill site. These results highlight zones electrically very conductive, they indicate the progress of the pollution plume in the under ground. The central part of the landfill site is the place under which the contamination affected depths of 20m. These data plead in favour of a strong mineralization of waters circulating in the trainings approached the site, whose potential source is bound to a contamination by leachate very mineralized and charged in organic matter.

12

Authors: HANNACHI A., GHARZOULI R. , DJELLOULI TABET Y.

Water is a limiting factor in the development of agriculture; scarcity is understood in terms of water stress and irregularity of the resource, two factors likely to increase with climate change. Face the challenge of ensuring the coverage of water needs for agriculture in Algeria , an active political mobilization of water resources has been implemented , as well as new management tools is the reuse of wastewater in agriculture . In Algeria, the presence of specific discharge standards for wastewater reuse in agriculture (Executive Decree n ° 93-160 of 10 July 1993 and Executive Decree No. 06-141 of 19 April 2006) and the presence of regulations fixing the modality wastewater reuse and the list of crops and their conditions of irrigation by treated wastewater (Executive Decree No. 07-149 of 20 May 2007 and the ministerial decree of 2 January 2012) is a promotion of projects reuse of treated wastewater. Leaders, public and private, have to make decisions on wastewater reuse in agriculture. They are faced with the need to exploit increasing amounts to meet ever greater demands. Integrated management of treated wastewater in Algeria, now institutionally recognized as a model of public- private partnership is the best approach to development and an effective and sustainable management of treated wastewater in the face of increasing water demands.

13

Authors: LAKEHAL M., ACHOUR B.

Normal depth plays a significant role in the design of open channels and in the analysis of the non-uniform flow as well. Currently, there is no analytical method for calculation of the normal depth in open channels, including the egg profile. Current methods are either iterative or approximate. They also consider, unreasonably, Chezy’s coefficient or Manning’s roughness coefficient as a given data of the problem, despite the fact that these coefficients depend on the normal depth sought. In this study, a new analytical method is presented for calculating the normal depth in an egg shaped conduit. The method takes into account, in particular, the effect of the absolute roughness which is a readily measurable parameter in practice. In a first step, the method is applied to a referential rough model in order to establish the relationships that govern its hydraulic characteristics. In a second step, these equations are used to easily deduce the required normal depth by introducing a non-dimensional correction factor. A practical example is considered to better explain the advocated method and to appreciate its simplicity and efficiency.

14

Authors: LARAKEB M., YOUCEF L., ACHOUR S.

The aim of this study is to test the efficiency of adsorption of zinc by use of goethite and an Algerian bentonite (bentonite of Maghnia). Adsorption tests are conducted in synthetic solutions of distilled water. The results showed that fixation of zinc (5 mg/l) on both adsorbents (1 g/l) is fast. Using the goethite, a removal percentage of 18 ℅ zinc was obtained after an equilibrium time of 30 minutes. After 20 minutes of stirring, the zinc removal by Maghnia bentonite was maximal with efficiency equal to 98,24 ℅. Removal efficiency of Zinc is improved with the increase of the dose of the adsorbent (0,1 to 8 g/l). Removal efficiencies decrease with the increase of the initial content of zinc (2 to 20 mg/l) and are interesting at basic pH. The adsorption tests showed that the Maghnia bentonite was more efficient than goethite, whatever the studied reaction parameter.

20

Authors: ACHOUR S., CHABBI F.

Drinking water is disinfected to inactivate waterborne pathogens. The most common form of disinfection is chlorination, although ozone and UV light are also used in some plants of the world. Disinfection equipment depends on the type of disinfectant used. In developing countries, the water disinfection problem is large and complex. There are a number of appropriate methods but chlorine continues to be one of the most popular options. In Algeria, it is the only method of disinfection used. Chlorine is a very effective disinfectant, it is relatively easy to handle, the capital costs of chlorine installation are low, simple to dose, measure and control and it has a relatively good residual effect. Chlorination efficiency depends on chlorine residual, contact time, type of chemical used, location in the treatment process, and on characteristics of the water being treated. The chlorine demand involves the reaction of chlorine with compounds in water, reducing the amount of chlorine available to kill microorganisms. Chlorination of humic substances in drinking water is known to produce mutagenic and carcinogenic compounds such as trihalomethanes. Because of their chemical quality, Algerian waters could lead to complex and competitive reactions during chlorination step. The widespread detection of chloroform and other organohalogenated compounds contamination in the water reservoirs appear to be largely a consequence of the use of chlorination for the disinfection of drinking water. Those documented as probable human carcinogens and mutagens have been detected in large amounts and have been considered as the major component of DBPs. Taking into account above drawn conclusions, greater efforts are needed to evaluate and set priorities for drinking water disinfection in Algeria. The challenge is to maintain the level of microbial protection while minimizing the exposure of the consumers to DBPs. If disinfection by chlorination is maintained, the best way to reduce THM generation is to reduce the concentration of precursors through various water treatment techniques prior to chlorination.

22

Authors: GOURINE B.

The present paper deals with the use of neural networks in the displacement and deformation fields modelling and analysis. The Generalized Regression Neural Network (GRNN) has proved its efficiency and reliability than the classical methods in the approximation of the displacement function. Based on the strain tensors, the deformation of GPS network is evaluated and represented according to a regular grid. In order to analyse this deformation, the concepts of deformability and deformation reliability are introduced, where the Monte Carlo method is employed to compute the significance degrees of the resulting tensors. At each stage of deformation field process, the GRNN neural network is used to perform an optimum interpolation of displacement field. The application concerns the GPS auscultation network of the Liquefied Natural Gas (LNG) underground tank of GL4/Z industrial complex (Arzew, Algeria). Composed of 119 points surrounding the LNG tank, the GPS network was observed between 2000 and 2006. The data concern the horizontal and vertical displacements of the network points according to local geodetic coordinates (E, N, U). The results show the performance of the adopted neural networks method in the generating and analysis of displacement and deformation fields. The most deformations measured are significant and at the deformability level. They support the physical interpretation by the presence of a rocky area at the WS side (landward) of the LNG tank which leads to compression and swelling, and the role of sea which acts as a warmer of freezing front causing important dilatations at the NE side (seaward).