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 ...
Read More
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, ...
Read More
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.
Fábio Ivan Ivan Seibel; Guilherme Otávio Moraes Giubel Giubel; Vandré Barbosa Brião; Mehri Shabani; Maxime Pontié
Abstract
As a result of population growth and potable water scarcity, an increasing number of reverse osmosis desalination plants are being installed and operated (more than 15,000 in the world). Reverse osmosis membranes tend to reach the end of the life cycle in around two to five years, becoming a solid waste. ...
Read More
As a result of population growth and potable water scarcity, an increasing number of reverse osmosis desalination plants are being installed and operated (more than 15,000 in the world). Reverse osmosis membranes tend to reach the end of the life cycle in around two to five years, becoming a solid waste. Recycling/repurposing these aged membranes could be a sustainable and profitable solution. This project aimed to transform end-of-life reverse osmosis membranes through the oxidation of their active layer using chlorine into nanoporous/microporous membranes, while searching possible applications for the resulting membranes. The results show that membranes oxidized at 10,000 ppm.h had a significant increase in permeability (3.1x), reaching NF-like capacity. On the other hand it was observed a decrease in the rejection of salt (4.35x) and acetaminophen (1.5x). Scanning Electron Microscopy (SEM) shows the positive effect of chlorine in the complete removal of particles deposited over the membrane. This oxidation condition also increased the average roughness (2.42x) of the membrane, as shown by Atomic Force Microscopy (AFM). Analysis by Fourier Transform Reflectance Spectroscopy (FTIR) suggests that chlorine oxidation replaced the hydrogen in the amide nitrogen. Both FTIR and SEM suggests the polyamide layer was not fully degraded. Application tests suggests that the recycled membrane can be used for the treatment of brackish and surface waters. The recycling of reverse osmosis membranes can be an alternative to simple landfill disposal, allowing owners to shift from disposal cost to revenue, as well as being a sustainable solution. The high permeability achieved on these oxidized membranes suggest many other NF/UF functions could potentially use recycled RO membranes.
Nafiseh Aghababaei
Abstract
Reverse osmosis (RO) has proven to be an efficient technique for desalination of seawater, brackish water, and reclaimed wastewater. However, the performance of RO desalination is sensitive to its design parameters and operating conditions. The purpose of this study was to modeling the removal of total ...
Read More
Reverse osmosis (RO) has proven to be an efficient technique for desalination of seawater, brackish water, and reclaimed wastewater. However, the performance of RO desalination is sensitive to its design parameters and operating conditions. The purpose of this study was to modeling the removal of total dissolved solids (TDS) and Rejection of different ions are reported from water of city of Bandar Abbas. The main purpose of this work was the prepared drinking water intrusion model. In this study, a design method based on a simulation technique has been developed for optimizing RO desalination systems. The design is made with the use of Hydranautics design software version 2011. In this paper main focus is on the design part with software. The desalinated water obtained from reverse osmosis at a pressure of 1.2 MPa showed rejections of approximately 88.49 % for SO4 2 −, 61.42 % for TDS, 70.34 for Cl- and 50.85 for Na+. It shows that software gives accurate design with least possible error and user friendly so world while accepted. Blended water, produced by mixing groundwater and surface, was proposed to optimize the produce drinking water with a recovery rate of 95 %. Reverse osmosis is an excellent alternative for the supply of water in Bandar Abbas.
