A Brief Note On Membrane Technologies And Its Effect On Water Quality

When nature limits our accessibility to water by droughts, we face no other choice but to turn toward the oceans for water. In that case we have to desalinate ocean water in order to purify it. The two most commonly known methods for desalination used around the world are Reverse Osmosis and Vapor Compression Desalination. We may take these two advancements in technology for granted in our daily lives and overuse the constantly flowing water. We need to take into consideration the amount of energy and effort required to purify water using these two processes. As the population grows in the drought areas the need for producing desalinated water is also going to increase, as

Due to the industrial revolution and the increasing in the world population, which leads to water scarcity of potable water and water for industrial applications. To cover the increasing demand of water we have to treat the polluted or saline water using the separation techniques to produce the potable and industrial water. This process it’s called, Water Desalination. Water Desalination is the process that treats the raw water by removing the suspended solids from the water. Sustain or the feed water sources may incorporate briny water or brackish water, seawater, ground water from wells, surface water (rivers and streams), wastewater, industrial feed and process waters. Desalination of seawater has the ability to produce enough amount of

Desalination of sea and brackish water is a common technique to alleviate the increasing shortage of fresh water in many areas of the world today. Nonetheless, desalination processes require large quantities of energy. In addition, the cost of the different desalination techniques is very closely linked to the costs of energy. Therefore, in a context of continuously rising energy costs and with the impending exhaustion of the conventional energy resources, the development of energy- efficient desalination technologies is a very attractive and promising prospect to solve these problems.

For example a state of the art water treatment technology that could be employed would be any pressure driven membrane filtration such as reverse osmosis, nanofiltration, ultrafiltration, and microfiltration make the Category A treated effluent in to

The modern techniques in water desalination include nuclear cleaning, change of state distillation, and reverse osmosis. This paper focuses on the most energy efficient technology available for each method, as this diminishes cost.

The process of desalination separates saline water into two parts. One of them, has a lot higher concentration than the original feed water known as the brine concentrate or simply as concentrate. The second part is one that has low concentration of salt (treated water or product water). There are two major types of technologies used for desalination and with that under each type, there’s 3 different types of methods used. One of the major types of technology of desalination is called thermal technology. The second type is called membrane technology.

Incredible water shortage in the Middle East region has compelled countries to reuse this water for many purposes. Treated wastewater can be used in agriculture, industry, recharging aquifers (Middle East Water Shortage). This method leads to conservation of traditional sources of water which further can be used “for meeting the demand for higher-quality water such as that for drinking, or for high value-added industrial and agricultural uses.” Also the climate fickleness’ influence will lessen by means of reuse. But there are few problems connected with leading treatment into usage. One of them are health and environmental risks (Baroudy 2005, 25-35). Purified in such way water contains bacteria, viruses and parasites (Middle East Water Shortage). Use of treated water can cause different infectious and gastrointestinal diseases. According to Baroudy even contact with this water sometimes can cause allergies and other dermatological illnesses (2005, 25-35). Another problem is that this water has some biological and chemical matter dissolved in it, which can obstruct soil pores. Clogged soil has less ability for leaking which leads to bad irrigation efficiencies (Middle East Water Shortage). But, of course, some standards with the purpose to limit these effects were elaborated. Toughening standards require financial investments (Baroudy 2005, 25-35). Process of waste treatment requires special equipment and construction of special water treatment

The increased cost of water consumption and wasteful require treatment process that is integrated with the circuits of water on the ground rather than as a subsequent treatment (19). From this point of view, membrane filtration offers a potential application. The processes that use membranes offer exciting possibilities for separation of dyestuffs and dyeing auxiliaries that reduce simultaneously hydrolysed color and biochemical oxygen demand /chemical oxygen demand of wastewater; generally used to treat effluent reactive dye bath, that could potentially reduce the volume of waste and recovery simultaneously salt (20). On the other hand, can be separated into two or more components the flow of fluid to its molecular size. The advantages of membrane filtration are because, it is fast with low space requirement and saturation can be reused. The disadvantage with membrane filtration method has a limited lifetime before it happens fouling of the membrane and the cost is also excessive (21). The choice of the membrane process, in the case of reverse osmosis, nanofiltration, ultra

Pressure-retarded osmosis (PRO) is a type of SGE that could potentially relieve the energy stress. In PRO, water is transported through a semi-permeable membrane from the feed to pressurise the water on the draw side, then the pressurised water flow pushes the turbine to generate electricity. Even though the theory of harnessing power by mixing high-saline water and low-saline water was first brought up in the 1950s, and the mechanism was first proposed by Leob in 1970s. PRO was not widely accepted due its low performance. And the use of reverse osmosis (RO) membranes was found to reduce the performance due to severe concentration polarisation. However, with the technological advancement in membrane technologies, PRO seems

Reverse osmosis water treatment can also be used to desalinate (remove the salt) from water which provides a fundamental water sources for some of the world’ major cities.

In a traditional osmotic situation, constituents gravitate towards traveling from high concentration to low concentration. When a solution of higher concentration is separated by a semi-permeable membrane, the solution of lower concentration flows towards the more concentrated side due to difference in osmotic pressure of the two solution [5]. It must be noted that higher the concentration of dissolved salt, the more important the osmotic pressure becomes, therefore, the greater the energy required for the separation process [40]. Reverse osmosis systems are based on molecular diffusion membranes made from extruded plastic film, metal foil

Bartram, J., Lewis, K., Lentron, R. & Wright, A. (2005). Focusing on improved water and

(ii) The new and successful application of the single step in-situ deposition of DA to immobilize the GO nanosheets onto the membrane surface was achieved. Applying GO nanosheets with the proper concentration rendered them tightly bound to the membrane surface without aggregations. This optimum modification also improved the membrane surface morphology, smoothness, hydrophilicity and antibacterial properties, resulting in improved desalination performance and better biofouling resistance. This simple and stable surface modification has great potential in the improvement of FO membranes.

In this section, a scale up study done by Fei Zhang et al in 2014 was reviewed. The system consists of microbial desalination cell system with post aerobic process as shown in figure 1. The volume of anolyte: sea water: catholyte is 60 L, 15 L and 30 L respectively (totaling up to 105 L). This is by far one of the biggest (if not the biggest) known scale up to date. Although it is still one order of magnitude away from typical pilot studies, it provides some insights in issues that cannot be seen from bench-scale studies. Through this scale up, the feasibility of the system in simultaneous treatment of seawater and wastewater was studied mainly by investigating the salt removal from seawater, COD removal from the wastewater and current generated by the system by varying the following influences:

Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from contaminated water. The goal is to produce water fit for a specific purpose. Most water is purified for human consumption (drinking water), but water purification may also be designed for a variety of other purposes, including meeting the requirements of medical, pharmacological, chemical and industrial applications. In general the methods used include physical processes such as filtration,sedimentation, and distillation, biological processes such as slow sand filters or biologically active carbon, chemical processes such asflocculation and chlorination and the use of electromagnetic radiation such as ultraviolet