جستجوی مقالات مرتبط با کلیدواژه « ion exchange » در نشریات گروه « مهندسی آب »

Although during the last two decades many studies have proved the effectiveness of the reverse osmosis system and this system has been used as a suitable and efficient method to treat drinking and industrial water and to desalinate the seawater, salt water, as well as sewage, it has some shortcomings, including sensitivity to ions, microorganisms, and organic matter in feed water causing problems such as scaling, fouling, as well as biofouling. Acidification of the permeate and its low pH are also other drawbacks of this system. This study is designed based on a two-pass reverse osmosis system, and each pass includes two stages (to provide higher system recovery). Moreover, ion exchange resin and AMBERPACK tank are used as pre-treatments considering the common problems of reverse osmosis system. Such fouling has been done to provide the required quality. It should be noted that by using the exchange resin system instead of the acid injection system, the TDS rate changed from 3.15 to 1.27 mg/L, which is equivalent to 59.68 % improvement, the LSI parameter, which in previous cases indicated severe fouling, ideally changed to -1.35 and -2.01. Also, the working pressure decreased from 13.7 bar to 12.5 bar, which indicates an 8.76 % improvement in working conditions.

The groundwater quality depends on different factors such as geology, lithology, properties of aquifer, land use, the physical condition of boundaries and etc. Studying of these factors can help users to manage the groundwater quality. This study deals with groundwater quality of an aquifer located in south-east part of Maharlou salt lake, Iran. This lake is located in south eastern of Shiraz and it is the outlet of the Shiraz swages. Due to over exploitation of groundwater from the aquifer, the gradient of water table is from lake towards the aquifer and therefore, saline water migrates in the aquifer. Salt water intrusion phenomena contribute to the deterioration of groundwater. In this research, groundwater types, maps of iso EC and iso ions, ion exchange in mixing of fresh and salt water, salinity variation of the groundwater in the profile of well water column and the salinity-time variation of the groundwater were studied. Gradual increase of salinity of groundwater with depth from top to down in the aquifer indicates that salt water is located under the fresh water. The time variation of physical and chemical parameters in groundwater discharged from a well shows that the saline water in the bottom of the aquifer moves up ward and destroys the quality of groundwater in the study area. Furthermore, Sachoun geological formation that has been formed by evaporite deposits and evaporation from shallow groundwater are other factors in decreasing the groundwater quality.