The role of membrane technologies in supplying drinking and industrial water in Tunisia: Conventional process and new trends (original) (raw)
Related papers
Bulletin of the Faculty of Engineering. Mansoura University
This paper discusses the performance and characteristics of desalination membranes used in treatment of water for potable use. In this study, The Desalination Economic Evaluation Program (DEEP) is a spreadsheet tool originally developed for the IAEA by General Atomics and later expanded in scope by the IAEA, The DEEP-5.1 version program allows designers and decision makers to compare performance and cost estimates of various desalination and power configurations. Desalination options modeled include MSF, MED, VC,RO and hybrid systems. This paper presents the results of the operational performance of RO units in experimental scale. The rate of decline of productivity for a period 38 Days is examined and described by simple power law function. The evaluation of the solvent and salt permeability coefficients with the time of operation is quantified. The results show the recovery, pressure and conductivity across the membrane for 38 days test run. Also, the results show the effect of chemical additives and operational parameters on the performance of the membrane during the cleaning. Based on such individual RO module data (one year) the product flow rate and Total Dissolved Solids (TDS) performance is calculated and RO module replacement ratio can be estimated. These developments can be utilized to improve the quality of surface seawater feed to the level comparable to, or better than the water quality from the well water sources. These new developments enable a more advanced RO system design which should result in increased reliability and lower water cost. And compare the result of reverse osmosis desalination conventional system with a mathematical model is built and solved with ROSA computer programs to get results for the design calculations of the reverse osmosis mode used to remove salt from the feed water. The principles of the reverse osmosis mode, the conditions and factors affecting their operation, are discussed. The number of stages with their arrangements in the reverse osmosis mode is calculated using the ROSA Program. A mathematical model and computer programs including all the mentioned cases are built and applied on the reverse osmosis mode of water stations. The results of these calculations are compared with the practical results and showed a fair good agreement.
Reverse osmosis membrane performance for desalination of Algerian brackish water
DESALINATION AND WATER TREATMENT
Desalination of brackish water (BW) is an effective approach to increase water supply, especially for inland regions that are far from seawater resources. Reverse osmosis (RO) is currently one of the most widely used methods of desalination in the world and widely used. The membranes used in the RO process play a vital role in determining the effectiveness of the desalination process depending on the water qualities feeds. Algeria represents the largest country in Africa characterized by two major regions the Alpine region in the north and the Saharan platform in the south. The purpose of this paper is to give an overview of the desalination process by assessing the performance of RO polyamide thin-film composite membrane (TW30-2540) purchased from Dow Chemical Company in terms of water permeability, salt permeability, selectivity and mass transfer coefficient using three different brackish water sources from the Alpine region. These regions are characterized by the high salinity of water. In conclusion, our study showed that TW30.2540 membrane could be used for desalination of brackish water with less cost compared with the currently used membranes BW30.2540, XLE 2540. The TW30.2540 membrane removed efficiently (97%) the salts referred by the total dissolved salt.
RO membrane autopsy of Zarzis brackish water desalination plant
Desalination, 2008
Tunisia, located in a semi-arid zone, has limited water resources. The shortage of good water quality in particular at the south regions required a brackish water desalination to supply these regions with potable water. Zarzis desalination plant, working since 1999, has revealed difficulties related to the loss of membrane performances. In the aim to determine the reason of membrane fouling, foulant layer were analysed. The membrane autopsy has achieved by different methods, such as TOC (total organic carbon) measurement, SEM (scanning electron microscopy), AFM (atomic force microscopy), FTIR (fourier transform infrared spectroscopy) analysis, diffraction by X-ray. Results show that the foulant layer composed mostly of SiO 2 , clay, organic matter (polysaccharide, protein), CaSiO 3 , Fe 3 O 4 , AlPO 4 , and CaSO 4 . The characteristics bonds obtained by IR indicate the presence of polysaccharides and proteins that constitute a source for further microbiological growth; this is the problem of biofouling. The metallic elements results of corroded stainless steel and internal coating of cartridges filter that are damaged by the silica particle rejected by sand filters. The scale of CaSO 4 and CaSiO 3 deposition is owing to the bad antiscaling efficiency. The results are presented and discussed in the light of new trends in material.
Diagnostic and membrane autopsy of Djerba Island desalination station
Tunisia is a semi arid country; the shortage of good water quality in particular at the south regions forced the government to desalt brackish water via membrane technology such as RO to supply these regions with potable water. Station of Djerba Isle established in 2000 by SONEDE has a nominal capacity of 15 ⋅ 10 3 m 3 per day and recovery rate of 75%; it is fed from an artesian well with the water salinity of 5500 ppm. Three RO units compose station; each one has configured in two stages a 2:1 array with six RO polyamide elements per pressure vessel. Membranes have been cleaned or replaced, during four operating years, as much time. In the aim to determine the reason of membrane fouling, this work occurs to analyse fouling layers. The membrane autopsy has achieved by different analytical methods, such as COT measurement, SEM (scanning electron microscopy), IR analysis, and diffraction by X-ray. Obtained results show that the deposit composed mostly of organic matter, silica, iron and CaCO 3 . The debris accumulate on upstream of pressure vessel is composed mainly of silica, metallic matter (iron and chromium) and aluminium phosphate.
Journal of chemical and pharmaceutical research, 2016
This paper is concerning the performance evaluation of small size brackish water reverse osmosis desalination units. The plant consists of a brackish water intake, pretreatment, two stages of reverse osmosis membranes in two lines, post-treatment and product water storage tank, nominal capacity of 252 m3/d of drink water. In this study, some important design factors and operating conditions are reviewed and the plant operating data are used to evaluate the unit performances.
Technological innovation for the production of drinking water by membrane processes
It is now common knowledge that membrane filtration processes can be considered as high performance separation techniques, not only in laboratory experiments but also in many industrial applications. With its strong development for the production of large-scale drinking water, the ultrafiltration on membrane hollow fibers appears as an appropriate, successful and economic technique for the purification of water in numerous applications. It often replaces more conventional desalination techniques. It has a capacity to eliminate not only small particles, but as a pathogenic, by including microorganisms , viruses, and some dissolved organic species. The choice of this technique for the production of drinking water from groundwater in a rural environment (Morocco) is the object of an experimental project: the technological innovation and industrial partnership, Morocco and Noon, French Pyrenees, "Development of Membrane Technique for the Treatment of the water".
Desalination, 2018
Fouling in membrane filtration processes is problematic. Causes are often specific depending on feed water constituents, the membrane and the chemical products used. Some fouling will badly affect membrane performance and cleaning will therefore be necessary. Cleaning can be supported by antiscalant treatments to reduce the risk of membrane fouling. However, some antiscalants may also lead to fouling. This paper presents the major problems of reverse osmosis plant in Jerba Island, namely the influence of antiscalant type on the water characteristics and membrane fouling. This was related to the increase of pressure drop, permeate conductivity and cleaning frequency. To identify the causes of membrane fouling, different investigations were carried out. Membrane autopsy, chemical analysis of feed water, follow-up of the operation parameters. The objective of membrane autopsy, by means of SEM/EDS, was to carry out a destructive analysis on a fouled membrane in order to identify the major causes of fouling. The results show that the film was composed mostly of organic matter, with significant presence of nitrogen, iron and silicates. These findings demonstrate how the antiscalants altered the water characteristics. Thus, the selection of the type of antiscalant should take into account the associated contribution to membrane fouling development.
DESALINATION AND WATER TREATMENT, 2010
Reverse osmosis (RO) desalination systems are being increasingly used in the world as an efficient, reliable and cost-effective technology. It is widely used for the production of municipal and industrial grade water treating seawater and brackish water. For instance, RO desalination has been widely and successfully used in Middle Eastern oil-producing countries. However, utilization of membrane plants has been spread throughout every region of the world as a viable economic alternative to traditional water treatment. To date, desalination of either seawater or brackish water in Jordan has been limited. In the case of seawater, Jordan has a very short shoreline on the Gulf of Aqaba and this is very distant from the main centers of population. This is further aggravated by the fact that these centers of population are at high elevations (Amman 1000 m above the mean sea level) and would therefore involve high pumping costs. Jordan does have reserves of brackish water, and a small number of brackish water desalination plants have been built. The Wadi Ma'in, Zara and Mujib desalination plant was officially inaugurated on the 18th of November 2007, the water production started on the 22nd of August 2006. Desalination is carried out using the reverse osmosis techniques. This is a Design-Build-Operate contract. The plant includes desalination of 55 MCM per year of water with a salinity of 1500-2000 mg/l. It shall provide Amman with 38 MCM per year with a TDS of 250 mg/l. This paper describes the performance evaluation of this plant so as to bring out the state of the art of its operation and maintenance. Detailed information on the plant design and engineering, water quality, plant personnel, and cost of operation and maintenance will be collected since commissioning of the plant. The performance of the plant is characterized according to the main parameters: quantity of water produced and quality of water.
ab s t r ac t Membrane bioreactor (MBR) technology has become a key component in water reclamation schemes for nearly 30 years due to the possibility of providing high quality water. The objective of the present study is to investigate the efficiency of MBR for the treatment of municipal blackwater. A pilot-scale MBR unit was installed and operated in the NRC, Egypt. Blackwater was primary treated through three chambers baffled sedimentation tanks. The effluent was then directed to the MBR. The reduction in the MBR permeates for COD and BOD ranged from 90 to 94% and from 90 to 97%, successively. The corresponding level of COD ranged from 34 to 76 mg/l, and BOD ranged from 6 to 18 mg/l. The average removal rate of ammonia and TKN was 97% and 94%, respectively. The averages values of some parameters in permeate were as follow: TSS, 0.6 mg/l; COD, 42 mg/l; BOD, 10 mg/l; NH 3-N, 5.8 mg/l. This indicates the advantages of membrane filtration over the activated sludge processes. Therefore, MBR process was found to be efficient for improving effluent quality. Such performance will guide the decision maker on the potential of MBR application and advantages of efficient wastewater treatment for irrigation purpose in Egypt.