Nima Asadi; Hamid Soleimanimehr; Aida Mohammad Sadegh
Abstract
Due to the quality of the water entering the water purifiers, sometimes the amount of solutes and hardness in the water is so high that after a short time, these systems become clogged or full. To solve this problem. Several methods have been proposed in this study, acid injection and its effect on reverse ...
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Due to the quality of the water entering the water purifiers, sometimes the amount of solutes and hardness in the water is so high that after a short time, these systems become clogged or full. To solve this problem. Several methods have been proposed in this study, acid injection and its effect on reverse osmosis system by wave software have been investigated. To ensure the condition and accuracy of the incoming water, the necessary tests were performed through the laboratory and the condition of the water and the number of ions and its salts were reported. By injecting acid into the inlet water, the pH value was reduced from 7.58, which is the normal pH of the water, to 5 by micrograph in 0.2 intervals, and after examination, the following results were obtained: With decreasing pH, the LSI number has a suitable decrease, so that at pH 6.1 and lower, the LSI number is negative and this indicates the lack of premature fouling. However, with this reduction, the acidic property of the treated water increases and the possibility of chemical corrosion of the industrial equipment used increases, on the other hand, by injecting acid and lowering the pH, the amount of TDS increased, which should be tried in different ways to minimize this amount. In comparison between injections of two acids performed under the same conditions, the amount of TDS at the time of H2SO4 injection at the pH limit was 10% less than the time of HCl injection.
Nima Asadi; Hamid Soleimanimehr; Ali Alinia-ziazi
Abstract
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, ...
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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.
