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Water is very important for human being and other living things. In human body, more than 70% are fluid such as blood and all these fluid are basically formed by water. Bone marrow needs water to generate blood then blood carries the oxygen from lung to whole body. Besides that, water can maintain human’s body temperature and provide natural material with mineral. Water is not only essential for human body, it is also playing an important role in our daily life activities, examples like washing clothes and food, bathing for personal hygiene and acting as solvent for all cleaning reagent. Consequently, water industries refer to a problem solver in this situation.
First of all, water industries are divided into three major types which are water purification, wastewater treatment and also the new type called desalination. For the water purification means purifying water to become the drinking water. Although natural water is drinkable for human but without any purification or method of killing gem, the natural water is harmful for human being nowadays. Purified water and natural water seems like no different when we look at it but sometimes we still smell the different, natural water might have some pungent smell. Natural water consists of a lot microorganism and bacteria inside it, just we can’t observe it with our naked eyes. In addition, water pollution is getting serious thus purification is necessary to ensure the drinking water is clean and not harmful to our health.
After that, another type of water industry which is very vital for the Mother of Nature is the wastewater treatment industry. Wastewater treatment refers to the processes of controlling the wastewater on Earth; this is the most important method to solve the water pollution. Wastewater is directing to the chemical wastewater from factories, wastewater from household and some water from polluted river or lake. The usage of wastewater treatment is to killing the gem/bacteria in the wastewater; remove solid impurities and odor smell. Irresponsible human behavior will make the wastewater treatment become more essential for the world.
The new type of water industry is about the desalination. Desalination is a meaning of transforming the seawater or saltwater into pure water or drinking water. Due to the natural water on the land is getting lesser and the population of human is increasing, hence we found out a new method to produce normal water from seawater. Seawater source is so much on Earth, so this method is highly developing around the world. Seawater cannot consume by human because it consists of high salt component such as NaCl, this cause our body unaffordable to consume the seawater.
Furthermore, we will discuss deeply about the process of water purification and desalination in this article.
The importance of Desalination and water purification industry
Water treatment process brings many importances to the society today. One of the importances of water treatment process is to ensure that water is more suitable to be used by industries and individuals. The purpose of water treatment process is to remove contaminations from water, so that it would be more suitable for it to be used. There are several processes that can be used to treat water such as filtration, disinfection that is majorly in use to clean water.
Water is the key to a person’s survival because without water survival is simply not an option. Hence, it is important to make sure water is purified in order to drink otherwise bacteria in the water can be harmful to your organs if drunk in normal consumption. According to a global research, a large number of people at their early ages die from water born diseases in most of the developing countries. Thus, it is very important to get the proper treatment of the water for a healthy living. Water treatment industry can be very helpful for the society today because they are saving the lives of many innocent human beings who die from fatal diseases such as cholera, typhoid which cause by consuming contaminated water.
According to United Nations statistics, the world’s fresh water consumption since the 20th century increased by 6-7 times higher than the population growth rate of two times, around 1.4 billion people lack access to safe and clean drinking water, or an average of every 5 people who have a lack of water. So, the idea of desalination plays a major role to provide us the constant supply of water as the sea water is an unlimited resource. Sea water desalination process is actually done by converting salty sea water into fresh usable water. Further purification of the sea water after the desalination process can convert it into drinking water. These industries are important to ensure that there is enough water supply as the population is growing and growing rapidly. These are the major roles of the water treatment plants in.
Water supply and demand
Water is one of the most important resources in our life and it is the major Earth’s natural resources. However the freshwater supply in our earth is a control resource, which means the total amount of freshwater, is limited. Most of the world’s water supply is saltwater stored in the oceans. Converting saltwater to freshwater is generally too expensive to be used for domestic, industrial and other freshwater uses.
About 97% of the water stored in the ocean is salt water. Only 3% of the world’s water supply is a freshwater where two-third out of the 3%, of that water is frozen, forming the polar ice caps, and icebergs. The remaining one-third of freshwater is available as either surface water or ground water; ground water accounts for two-thirds of this amount. Surface water is water that is visible above the ground surface, such as rivers, ponds and lakes. Ground water is water that either fills the spaces between soil particles or penetrates the cracks and spaces within rocks.
The demand for water supply includes water consumption by the domestic, industrial, commercial and other sectors. In addition to this, the total amount of water that needs to be produced, and hence the total water demand includes provisions for water lost as a result of the leakages between the source (treatment plant) and the end users of consumers. Malaysia, like the rest of the world, is faced with a growing population. The population of Peninsular Malaysia will be more than double its size from 18.1 million in 2000 to 38 million in 2050 as reported in the National Water Resources Study (2000) thus the population growth and socio-economic development are currently driving a rapid increase in water demand.
The government is now working on the creation of an industry structure to purified water that will ensure long-term sustainability of the water supply and sewerage services industry. Purified water is water from any source that is physically processed to remove impurities. Distilled water and deionised water have been the most common forms of purified water, but water can also be purified by other processes including reverse osmosis, carbon filtration, micro porous filtration.
Prospect of water industry in Malaysia
Nowadays, the water industry in Malaysia is filled of challenges. There is either too much, too little, polluted or inaccessible water to meet the needs of our nation. As the increasing of demand to the quality of life, peoples are pursuing for an abundance of safe, low cost and high quality water. Globally, more than 90% of water and sanitation systems are publicly owned and operated. However, a trend that industry experts acquired smaller utilities has been increasing. This phenomenon is called consolidation. There also was an increase in privatization-private companies that contract to operate or to purchase the public utilities. Moreover, many larger systems were investing in new testing and treatment methods.
Under Malaysian conditions, erosion by water and the decay of nation’s of pipes that transport water into homes are the most significant. As pipes corrode, water pressure decreases and foreign materials such as bacteria and debris may enter the system. In order to reduce the negative health effects to humans, government officials flush out the water and add large doses of chlorine to eliminate contaminants. However, this is a short-term solution. Obviously, the country’s water-pipe system, much of which is over one hundred years old, needs a major overhaul. Increased privatization of the water system is being seriously considered to help alleviate the plight of country’s water as the government can receive funding for structural adjustment programs. This is because private water companies have a high potential of bringing efficiency, savings, and environmental responsibility to communities, cities and the country.
Besides that, as we know that fresh water that is available for human use is just 1 percent of the total water supply, and that supply is dwindling as supply cannot keep pace with demand. Thus, the prospect of water industry may be focusing in the alternative to increase the freshwater. Since most of the earth water is seawater, desalination technology has arisen as a potential alternative to solve the problem of water shortage. Desalination has been present throughout the 125 countries and territories around the world, the world’s desalinated water to feed about 5% of the population. In fact, desalination is an excellent way to solve water shortage problems in many countries. This is indeed a strategic choice as its validity and reliability has been more widely recognized. Research indicates that the cost of producing water from desalination is often less than half that produced by the distillation method of processing water. Improvements in effienciency have led to reduce energy consumption, cheaper processing costs and a superior product being produced.
The Impact On the Environment
As our world industrialised, water pollutions are getting serious. There are three main types of water pollutions caused by human activities, which are domestic sewage, industrial wastewater and agricultural wastewater. In these wastewaters, contain pathogens, detergents, toxic waste, chemical waste and heavy metals. These harmful chemicals not only poison aquatic organisms, also affect sources of drinking water, and pollute our environment.
Toxic wastes, generally, are not easy to metabolise out of body of organisms. Wastes tend to bioaccumulate inside the organisms. The bioaccumulation of toxic wastes not only happen in single organism, but all members from food chains. The concentration of toxic wastes gets higher as the trophic level going up.
Not only that, the agricultural wastewater contains fertilizer, pesticide and also the fungicide. These pollutants cause the eutrophication. It is caused by excessive nutrients in the wastewater, and it brings the algal blooms and red tide. These leads to fish kills as algaes consuming most of the oxygen in the water.
In a nutshell, water pollution can lead to a lower biodiversity. The decrease of biodiversity means that the variation of life decreased, and it affects the balance of ecosystem. It is important to maintain the balance of ecosystem, species of organisms will decline if the ecosystem does not balance. It will be a bad circle.
Water industry helps in collecting the wastewaters from different parts to the water treatment plants. Also, water industry helps in controlling the quality of water. Before discharging the wastewater back to our ecosystem, the water is treated so it reduces the effect toward the environment.
It also improves the water quality which means that provides not only the better quality of life, and save the environment for the future. Furthermore, it maintains the balance of aquatic ecosystem. As the contaminated wastewater not flowing into river and the sea, the aquatic environment will be free of dangerous and toxic wastes. The world cannot stand without water industry. Water industry gives us a solution to the world, a hope to the future.
Reverse osmosis is one of the water purification method that is popular in water treatment industry. Just as its name implies, water goes on the osmosis process another way. Normally, the solvent, which is water will go through the semipermeable membrane that having many tiny pores, from low solute concentration side to the high solute concentration side.
However, for the reverse osmosis, a pressure is applied on the high solute concentration part. The pressure can be drove by electricity or it may get from the pressure exchanger. Thus, water molecules are forced to pass through the membrane to the low solute concentration side. By this way, clean water can be collected on the other side.
There are three common membrane materials, which are polyamide thin film composites (TFC), cellulose acetate (CA) and cellulose triacetate (CTA). In generally TFC membranes are stronger and more durable among these three membranes. CA and CTA give a better toleration to chlorine. For different purpose, specified membrane will be used.
Reverse osmosis can be used in residential, commercial and industrial water filtration, also the seawater desalination. By this method, impurities in the water can be removed to clean water. These impurities include ions, volatile organic compounds (VOC’s), pesticides, and salts. This is because those impurities are larger than than the pores so they cannot pass through it. Water molecules are allowed to pass through the membrane as it is small enough. Impurities,yet will be left behind the membrane.
The waste streams flow out and the pressure is high. Later, the streams go through the pressure exchanger to transfer the waste pressure to the low pressure fresh feed. Then, the low pressure fresh feed will be pressurised. The recycle of waste pressure can save the cost of running the reverse osmosis system. The water flowed out is now clean and ready for purpose of drinking or other uses.
Coagulation, flocculation and sedimentation
Natural and waste water include small particulates. Coagulation and flocculation processes are intended to form particles large enough to be separated. The small particulates are suspended in water forming a colloid. The particles with the same charge repel with each other and this prevents them from combining into larger particulates to settle. Thus, some chemical and physical techniques are applied to help them settle. The phenomenon is known as coagulation.
To assist in the removal of colloidal particles from suspension, chemical flocculation is required. The process water will then enter a flocculation chamber, where further chemicals may be added depending upon the raw water characteristics and the level of treatment to be achieved. Gentle mixing during this stage allows particles to agglomerate and form settleable flocs. Starch and multiply charged ions are often used. The dirty water is cleaned by treating with alum, Al2(SO4)3.12 H2O, and lime, Ca(OH)2. These electrolytes cause the pH of the water to change due to the following reactions:
Al2(SO4)3.12 H2O, -> Al(aq)3+ + 3 SO4(aq)2- + 12 H2O
SO4(aq)2- + H2O -> HSO4(aq)- + OH- (causing pH change)
Ca(OH)2 -> Ca(aq)2+ + 2 OH- (causing pH change)
The slightly basic water causes Al(OH)3, Fe(OH)3 and Fe(OH)2 to precipitate, bringing the small particulates called “flocs” with them and the water becomes clear.
Flocculation usually follows by sedimentation, the heavy floc particles settle to the bottom of treatment tanks, allowing for their separation from the water. It works best with relatively dense particles (e.g. silt and minerals), while flotation works better for lighter particles (e.g. algae, color). A big settling tank is needed so that it takes a long time to get through. Inlets and outlets are designed so the water moves slowly in the tank. Long and narrow channels are installed to let the water to snake its way through the tank. The settled particles, sludge, must occasionally be removed from the tanks. The water is next ready to be filtered. Sedimentation is used in pre-treatment and wastewater treatment.
Thermal Distillation and Electrodialysis
In the process of desalination, after the reverse osmosis, it comes to the thermal distillation process. Heat is used in the thermal distillation for desalination. It boils the salt water to causes the water to vaporize, at the same time, the salt is left behind. Most of the salt is sodium chloride (NaCl). After that, the vapor will moves to a second container to condensed and collected. The boiling process of water uses up a lot of fuel to make the salt water to vaporize so many alternative processes can be considered. These processes are called multistage flash distillation (MSF), multiple effect distillation (MED), and mechanical vapor compression distillation (MVC). All these process can reduce the energy that used to boil the water with reducing the water’s boiling point by decreasing the water’s vapor pressure.
The mechanical vapor compression distillation (MVC) is a process which evaporates the sea or saline water is derived by the heat application delivered by compressed vapor. This process able to increase generate additional amount of vapor by using the latent heat during the condensation when the vapor’s compression increases both of the temperature and pressure of the vapor. The multistage flash distillation is a thermal process with the low temperature of obtaining fresh water by recovering the vapor of boiling sea water in a sequence of vessels, (called effects) each maintained at a lower temperature than the last. Due to the boiling point of the water reduced as the pressure reduced, the heat energy of the vapor boiled off from one vessel is able to heat the another vessel thus only the first vessel require the heat energy from other source to heat up the sea water.
Furthermore, another process of desalination process is electrodialysis that used to separate the other ions and water ions by relying on the salt ions’ electrical charge. In this process, the water is pre-treated by reverse osmosis thermal distillation hence then transfer to a membrane stack. Two electrodes, a positive electrode located on one side of the stack and a negative one on the other, an electrical current is conducted through the water. The ions are attracted to the oppositely charged electrodes and flow through membranes that are designed to trap either the negatively charged ions (anions) or positively charged ions (cations). Once the ions are trapped, fresh water will filtered out.
Water filtration improves the overall taste of tap water, appearance and smell. Water filters are design to remove several harmful chemicals found in drinking water. At the moment, there is no better way to make sure that the water you are drinking is clean. Compare the differences between a glass of tap water and bottled water. You will realize that tap water is cloudy and it smells like bleach. There are four stages involved in water purification process:
-Prevents large debris from entering the System
2. Sediment Filtration
– 5.0 Micron Sediment Filtration
3. Carbon Block Filtration
– Chemical removal and 0.5 Micron Filtration
4. Ultraviolet Treatment
– 99.9999% Elimination of Bacteria / Virus
– Ultraviolet exposure of 16,000 mw/cm2 or greater
Pre-filtration is the first process of water filtration, it screens the water source starting from the point of entry. These pre-filter screens are connected to the inlet hose. This is important in preventing the filtration system that turns out to be plugged with rocks, faeces, mud and other large debris.
Sediment Filtration is the second stage. In this stage, the water will pass through a sediment filter. In the sediment filter it gives five micron filtration and it expands the life of the carbon filter by eliminating invisible sediments that will impulsively block the filter. Sediment filtration would include the removal of dirt, mud, sand, scale, silt and other suspended solids in the water.
Carbon block filtration is the third stage of the filtration process. This process has two different processes. The first process is called mechanical straining, carbon is compressed into a solid block of material. Each molecule of water is pushed through the microscopic pores of carbon that strain out substances efficiently. The second is called chemical bonding, it uses an activated carbon which has a trivial electro – positive charge added to it, making bonding agents to impurities and chemicals even more attractive. When the water is pushed through the solid carbon block, it is forced to slow down and the increased quantity of contact time with carbon allows the carbon bonding to take place.
The final stage of the filtration process is the ultraviolet treatment. After the water is cleaned by the carbon filter, the next step is to expose it to an extreme dosage of UV light. The UV light it produced will destroy microorganisms by changing their DNA structure.
Aeration and Disinfection
Aeration is a water treatment process where water is brought into the contact with oxygen. This is to increase the oxygen content in the water, to reduce the carbon dioxide content in the water, and to remove organic compounds such as methane, hydrogen sulphide and other volatile which is responsible for taste and odour of water. These will result in good drinking pure water.
High iron and manganese content in water will cause a bitter taste. Aeration is widely used for the treatment of high iron and manganese contaminants water to convert the dissolved ferrous and manganese compounds into insoluble ferric and manganese hydroxides. These can be removed by sedimentation or filtration process.
There are many instruments and systems designed to aerate wastewater. These range from simple floating splashes and rotors to high-maintenance diffused air systems using membranes and complex man folding and piping layouts. These systems are designed to inject oxygen to every part of the water. The end result is better than water treatment with higher removal rates of microorganism contamination.
Disinfection is an important step in ensuring that water is safe to drink, and limiting the effects of organic materials, suspended solids and other contaminants. It destroys microorganisms that can cause disease in humans. Primary methods of disinfection are chlorination, chloramines, ozone, and ultraviolet light. Other methods include chlorine dioxide, potassium permanganate, and nano filtration. Since certain forms of chlorine react with organic material naturally present in many water sources to form harmful chemical by-products.
Common industrial method of disinfection is chlorination, where the chlorine gas is released to mix with water. The mixing and contact time must be provided after an injection to ensure complete disinfection of pathogens and other microorganism. Thus it kills microorganisms and it may be necessary to control the pH of the water. One chlorination had been done, the water will be finalized by some tests to make sure the water is neutral, clean and pure. Finally the water will be send to storage for the domestic, industrial, and commercial uses.
Role of Chemical Engineer in the Water Treatment Industry
Basically the role of a chemical engineer in a water treatment industry is mainly referring to the technical skills that the chemical engineers obtained because chemical engineers have to conduct the water treatment processes in the industry.
Firstly, we talk about the role of chemical engineers before the process and industrial plant in the water treatment industry is formed. For a chemical engineer, the first mission has to do will be understood about the requirements of the water treatment industry to conduct a process with a specific industrial plant. For our case, the chemical engineer must know how to conduct a process of water purification to product drinking water. Chemical engineers must able to design an industrial plant which consists of different types of components to complete the process and get the desired product. The components that might involve in the plant are compressor, mixer, cooler, filter (separator).
Furthermore, whether designing the plant, chemical engineer also may concerns about the chemical substances used within the process in the plant. The chemical substances added into the water along the process must not be harmful to consumers due to the water as output is the drinking water for human to consume. Some more, the costs for the substances and material used to build the plant and those components inside it must be save up to the lowest. Chemical engineers need to save the cost for the company and also form the product which is the drinking water with the highest efficiency. Besides that, chemical engineer has to evaluate the chemical process technology and equipment which suitable in the plant. The most important role of chemical engineer in this industry is determining the production specification.
Once the plant completely designed, the most essential job that needs the chemical engineer to accomplish is establish and conduct quality control programs, operating procedures and control strategies to ensure consistency and adherence to standards for raw materials, products and waste products or emissions. When the process is running, there also something necessary for chemical engineer to provide checking for the plant and make a suitable maintenance on the processing units. Thus, chemical engineer is playing a very important character in the water treatment industry.
Skills/Knowledge required by Engineer
As an engineer, there are many skill and knowledge required to smoothen the task that have to conduct by engineer. The skill and knowledge required by engineer can be categories into six parts which are technical skill, computer literacy, communication skill, management/finance, international awareness and respect for diversity.
Engineer requires the technical skill and knowledge to conduct and control the processing units in the plant. The technical skill is about the mathematics, chemistry, physics, mechanical and electrical knowledge. In the water industry, chemical engineers refer to separating dangerous materials from good water as a treatment train. At various stages in the multistage treatment process, unwanted constituents are separated using vacuum or pressure filtration, centrifugation, membrane-based separation, distillation, carbon-based and zeolite-based adsorption and advanced oxidation treatments
Computers are used every day for communications, simulations, budgeting, monitoring controls and word processing hence the computer literacy is very important to improve the efficiency and accuracy of the simulations and assumption that did by chemical engineers. Before chemical engineers design a plant, they have to do some simulation by using some professional programs or software in the computer such as Aspen Technology Programs.
Engineering involves working with others and communicating but not only deal with machines so that others able to understand and support the idea provided individually. Consequently, communication skill also must be trained by chemical engineers. When the time chemical engineers present their project or proposal, the others who listening and watching able to fully disgust what are the points and idea about.
Management and finance are always the necessary knowledge for everyone in the society including engineers. Many decisions an engineer makes have business consequences. Understanding the business principle can help engineers become more effective. In finance aspect, chemical engineers require to know clearly how to manage a team because engineers can be leaders which work together with others.
For the engineers, they are working in a global market requires an understanding of cultural, geographic, economics and environmental factors that influence the decision which made by engineers. International awareness means chemical engineers have to be caution with all the response and effect from the market around us.
Lastly the respect for diversity, engineers regularly work in group setting so being able to interact effectively, professionally and respectfully with others will make you a more capable team player. A good engineer team leader must respect all the colleagues so that everyone can work together without any conflict.
In a conclusion Water treatment is an important processs in our modern life, due to the lack of natural fresh water and increase in population. Many new technology method has been introduce to water treatment industry nowdays. The raw sea water have to go through a certain number of processes strating with either reverse osmosis or thermal distillation to make it usable. Besides this two processes, an electrodialysis process method can also be used. A further water treament process need to be done to make it drinkable, the processes consist of coagulation method, followed by flocculation and sendimentation. A further filtration process is done and finally aeration and disinfection process will take palce before the water is kept in a storage. This processes can be used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the concentration of such contaminants so the water becomes fit for its desired end-use. One such use is returning water that has been used back into the natural environment without adverse ecological impact.
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