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UV System WHAT IS UV DISINFECTION SYSTEM AND HOW DOES IT WORK? UV Disinfection System is an extremely effective way to combat microbial contamination in water. However, microbes have to be exposed to UV-C light in the proper amount in order to effectively disinfect the water. UV Disinfection Systems are used in many different applications ranging from the purification of drinking water in individual homes to disinfecting water supply of entire townships. UV treatment for water is recognized as the safer and more cost-effective way to disinfect water for industrial applications. UV sanitization is useful in almost any application where microbial free, safe and pure water is required; and where there is a chance of the water being contaminated before it reaches the final point of use. How Does UV Disinfection System Work? UV light disinfects by penetrating microorganisms and destroying their DNA. DNA plays an important role in organisms’ functions and reproduction hence destroying the DNA prevents the organism from being active and multiplying. This UV energy (wavelength of 240-280 nm) is also naturally found in sunlight in very small quantities. The same energy is produced in stronger intensities with help of high mercury discharge lamps, commonly known as UV lamps. No bacteria, viruses, molds or their spores can survive when exposed to the correct dose of UV light. Therefore UV is considered as the best solution for water sterilization. Industrial Applications of UV Disinfection System Ultraviolet disinfection system is not simply a lamp inside a pipe. The UV Reactor must be designed to ensure that all microbes receive sufficient exposure to the UV light (dose).Based on the hydraulic properties of water; the reactor needs to be optimized to guide the flow in a manner so as to maximize residence time and boost turbulence. Well designed UV systems are producing consistently exceptional results in the industrial applications. Few Examples : Food and Beverage – UV disinfection system can help to achieve quality of water as per specifications laid down by the FDA ( Food and Drug Administration ) Bio- Pharmaceutical – Water used in Pharmaceutical and healthcare products and for CIP (Cleaning in Place) must be free of chemicals like chlorine, ozone, and pathogens. Most pharmaceutical companies depend on UV systems for water disinfection. Cosmetics – Water that is free of microorganisms and toxins ensure quality and enhance the shelf life of cosmetics. UV Sterilization is the preferred choice for the cosmetic industry across the globe. Centralized Drinking Water – A UV system is an easy, affordable solution to ensure pure water in each and every tap of your home or office. Waste Water Disinfection and Reuse – To combat the problems of water scarcity and rising cost of fresh water, UV Disinfection can help by treating the waste water in the tertiary stage. UV systems that are specially designed for wastewater can thus disinfect wastewater so that the water can be reused for secondary purposes such as flushing and gardening. Swimming Pools – Traditionally, chlorine has been in use to ensure clean water in swimming pools. However, it is increasingly being known that with chemical disinfection, chemical reacts with many other organic matters to form hundreds of new chemicals which are harmful. While UV is recognized as safer and more cost effective way to disinfect swimming pools. Benefits of UV Disinfection System Natural – UV is nature’s way of purification. Environmentally Friendly – No Toxic by-products are formed during UV disinfection process Effective – All known microorganisms are susceptible to UV light Economical – Lowest operating cost amongst disinfection systems Safe& Chemical Free – No addition of chemicals hence no danger of overdosing Fast – It is In-contact purification therefore Instant Easy to Manage – Well designed systems like the Alfaa UV systems come with many advanced features like CFD (Computational Fluid Dynamics), high-efficiency electronic ballasts, and extremely precise UV intensity monitors which make them highly effective and hence easy to manage. Does a UV Disinfection System need periodic maintenance? There can be some cases where the water is not adequately pre-treated and turbidity levels are low. In such cases, routine inspection and cleaning can be carried out every 6 months. In the case of high turbidity and hardness, the cleaning frequency might need to be increased. Finally, the UV lamp has a limited life and must be replaced once it is exhausted. In the unlikely event of premature failure of the lamp, the monitoring circuit will provide the signal to advise replacement.
Disinfectants Copper-silver ionization Metals such as copper and silver can be used for water disinfection, if they are ionized. Process history Archeological excavations show, that people have been using copper for more than 10000 years and have been using silver for more than 5000 years. Copper can be easily extracted and processed. More than 7000 years ago people developed a copper extraction mechanism for copper ores. The Roman empire gained most of its copper from Cyprus, the isle that gave copper its name. Nowadays copper is mainly extracted from ores, such as cuprite (CuO2), tenorite (CuO), malachite (CuO3•Cu(OH)2), chalcocite (Cu2S), covelite (CuS) and bornite (Cu6FeS4). Large deposits of copper ores have been found throughout the US, Chili, Zambia, Zaïre, Peru and Canada. Silver can be obtained from pure deposits, from silver ores such as argenite (Ag2S) and horn silver (AgCl) and combined with ore deposites that contain lead, gold or copper. Both copper and silver have been applied for centuries because of their biocidal mechanism. The Vickings used copper strings on their ships to prevent the growth of algae and shells. Modern ships still use the same technology. Most anti-fouling paints contain copper, reducing the number of marine species growing on the walls of ships. Because of this measure, ships can reach their destination faster. Nomads used silver coins to improve drinking water quality. Well water containing copper and silver coins is very bright, due to the biocidal effect of these metals. Since 1869 various publications have appeared on disinfection properties of silver. Some European and Russian villages have been using silver for drinking water treatment for many years. Copper-silver ionization was developed in both Europe and the United States in the 1950’s. Copper-silver ion - Process Copper-silver ionization is brought about by electrolysis. An electric current is created through copper-silver, causing positively charged copper and silver ions to form. Copper-silver ionization brings us back to basic chemistry: an ion; an electrically charged atom has a positive charge when it gives up an electron and a negative charge when it takes up an electron. A positively charged ion in called a cation and a negatively charged ion is called an anion. During ionization, atoms turn into cations or anions. When copper-silver ionization is applied, positively charged copper (Cu+ and Cu2+) and silver (Ag+) ions are formed. The electrodes are placed close together. The water that is disinfected flows past the electrodes. An electric current is created, causing the outer atoms of the electrodes to lose an electron and become positively charged. The larger part of the ions flows away through the water, before reaching the opposite electrode. Generally the amount of silver ions at a copper ion rate of 0, 15 to 0, 40 ppm lies between 5 and 50 ppb. The ion concentration is determined by the water flow. The number of ions that is released increases, when electric charges are higher. When copper ions (Cu+) dissolve in water, they are oxidized immediately to form Cu2+ ions. Copper can be found in the water in free form. It is commonly bond to water particles. Copper (Cu+) ions are unstable in water, unless a stabilizing ligand is present. Applications of copper-silver ionization Copper-silver ionization is suitable for a large number of applications. It became of interest when NASA used copper-silver ionization for drinking water production aboard Apollo space ships in 1960. The ion generator that was used was the size of a matchbox. Because of copper-silver ionization, drinking water could be produced safely in space without the use of chlorine. In England, copper-silver ionization is applied in about 120 hospitals successfully for the deactivation of Legionella bacteria. In the United States, copper-silver ionization is mainly used for swimming pool water disinfection. Copper-silver is often used to limit disinfection byproducts formation during chlorine disinfection. Because of its specific properties, copper-silver ionization is very suitable for fishpond disinfection. Copper-silver ionization is not dependent on temperatures. It is active in the entire water system. Copper-silver ionization is used by water bottling companies and companies that recycle water throughout the United States. The disinfection mechanism of copper-silver ionization Electrically charged copper ions (Cu2+) in the water search for particles of opposite polarity, such as bacteria, viruses and fungi. Positively charged copper ions form electrostatic compounds with negatively charged cell walls of microorganisms. These compounds disturb cell wall permeability and cause nutrient uptake to fail. Copper ions penetrate the cell wall and as a result they will create an entrance for silver ions (Ag+). These penetrate the core of the microorganism. Silver ions bond to various parts of the cell, such as the DNA and RNA, cellular proteins and respiratory enzymes, causing all life support systems in the cell to be immobilized. As a result, there is no more cellular growth or cell division, causing bacteria to no longer multiply and eventually die out. The ions remain active until they are absorbed by a microorganism. The disinfection applications of copper-silver ionization Swimming pools and copper-silver ionization In the United States, copper silver ionization is applied as an alternative for chlorine disinfection. Chlorine use can be reduced by 80 percent. However, another disinfectant should be added in addition to copper-silver. This is because copper-silver cannot remove organic matter, such as skin tissue, hairs, urine and skin flakes, from swimming pool water. Cooling towers and copper-silver ionization Cooling tower water requires disinfection, to prevent the growth of microorganisms. This can be brought about by a combination of copper-silver ionization and chlorine disinfection. Chlorine concentrations that are required are much lower. Copper-silver ionization can also be used to kill Legionella bacteria in cooling towers. Legionella in hospitals and nursing homes and copper-silver ionization Copper-silver ionization is applied in hospitals and nursing homes to prevent the distribution of Legionella bacteria. The main source of Legionella distribution is the warm water system. Circumstances in warm water systems are ideal for Legionella bacteria to grow and multiply. Contagion mainly takes place through shower steam. Copper-silver ionization can sufficiently kill Legionella bacteria. Copper-silver can actively deactivate Legionella, as well. Drinking water and copper-silver ionization In the United States, several drinking water production companies use copper-silver ionization as an alternative for chlorine disinfection and to prevent the formation of disinfection byproducts. The standard for trihalomethanes was decreased by EPA from 100 to 80 microgram per litre. When copper-silver ionization is combined with chlorine disinfection, it is an excellent disinfection mechanism to deactivate viruses and bacteria. What are the terms of copper-silver ionization? The affectivity of copper-silver disinfection depends on a number of factors: Firstly, the concentration of copper and silver ions in the water should be sufficient. The required concentration is determined by the water flow, the volume of water in the system, the conductivity of the water and the present concentration of microorganisms. Secondly, the electrodes should be in good condition. When the water is hard or fouling takes place as a consequence of water hardness and quality, there will be a decrease in electrode release and the additional effect will decrease. By using pure silver and pure copper, the supply of copper and silver ions can be regulated separately. These electrodes suffer from less limestone formation and fouling. Thirdly, the affectivity of copper-silver ionization depends on the pH value of the water. When pH values are high, copper ions are less effective. When the pH value exceeds 6, insoluble copper complexes will precipitate. When the pH value is 5, copper ions mainly exist as Cu(HCO3)+; when the pH value is 7 as Cu(CO3) and when the pH values is 9 as Cu(CO3)22-. Fourthly, copper-silver ionization affectivity is determined by the presence of chlorine. Chlorine causes silver chlorine complex formation. When this occurs, silver ions are no longer available for disinfection. How effective is copper-silver ionization? Copper-silver ionization can deactivate Legionella bacteria and other microorganisms in slow-running water and still water. Legionella bacteria are very susceptive to copper-silver ionization. Copper-silver ionization also takes care of bio film. Copper remains within the bio film, causing a residual effect. It appears that copper-silver ionization addition causes the number of Legionella bacteria to diminish. After a short period of time, however, the number of Legionella bacteria will rise again because they can also be found in the bio film. Copper that stays behind in the bio film takes care of these bacteria. When copper and silver ions are added to water constantly, the concentration of Legionella bacteria remains low. The deactivation rate of copper-silver ionization is lower than that of ozone or UV. A benefit of copper-silver ionization is that ions remain in the water for a long period of time. This causes long-term disinfection and protection from recontaminations. Copper and silver ions remain in the water until they precipitate or absorb to bacteria or algae, and are removed from water by filtration after that. The benefits and drawbacks of copper-silver ionization Benefits Copper-silver ionization affectively deactivates Legionella bacteria and bio film and it improves water quality. Copper-silver ionization has a larger residual effect than most other disinfectants. Copper and silver ions remain in the water for a long period of time. Because of its local affectivity, the effect is larger than that of UV. Copper-silver is effective throughout the entire water system, even in dead-end points and parts of the system that contain slow-running water. Copper-silver use affectivity does not depend on water temperature. When copper-silver is used, less maintenance to the water system is required. Copper-silver is non-corrosive; it causes less strain on the distribution system. Because of a decrease in the use of chemicals, the lids and pumps are not affected. Furthermore, shower heads, tanks and taps are not contaminated. When copper-silver ionization is applied, there are no transport and storage difficulties. Drawbacks Copper-silver affectivity depends on the pH value of the water. At a pH value of 9, only one tenth of all Legionella bacteria are removed. When dissolved solid concentrations are high, silver will precipitate. This means silver ions are no longer available for disinfection. Silver ions easily react with chlorines and nitrates that are present in the water, causing them to no longer be effective. Some species of microorganisms can become resistant to silver ions. They can remove metal from their systems or convert it to a less toxic product. These microorganisms can become resistant to copper-silver ionization. Although it is suggested that Legionella bacteria can develop resistance to copper-silver ionization, this disinfectant still appears to be effective for Legionella deactivation. To affectively kill pathogenic microorganisms, copper and silver ions should be present in the entire water system. When the system is used little and the water flow is quite slow, or when there are dead-end points in the system, this can causes problems for disinfection. The health effects of copper-silver ionization Insufficient evidence have been found on the possible health effects of long-term exposure to copper-silver ionization. Little is known on the general health effects of copper-silver ionization. Legislation for copper-silver ionization EU The European Union does not dictate any standards considering silver concentrations in the water. Copper, however, has a maximum value of 20 μg/L, because it corrodes waterworks. Copper concentrations should be measured in taps. (EU Drinking water directive 98/83/EC, 1998) WHO The WHO does not dictate any standards considering the concentration of silver as a drinking water disinfectant, because the organization found the available data to be insufficient to recommend a health standard. (WHO, Guidelines drinking water quality, 3e editie) USA The United States dictate a maximum value of 1 mg/L of copper and a maximum value of 0, 1 mg/L of silver. (EPA, National Secondary Drinking Water regulations, 2002) How is copper-silver ionization controlled? When copper-silver ionization is applied, a log of the entire system must be kept. Water analysis and tests must be conducted to prove system affectivity, because this concerns an alternative disinfectant. The first analysis round takes place before the application of copper-silver ionization. Copper and silver concentrations in the water are measured and the amount of Legionella bacteria and the aerobic growth number at 22 ˚C and at 37 ˚C are determined. When the system is placed, the outcome of water analysis should be checked and reported monthly.
How to select the right water purifier When it comes to caring for your family, you need to avoid taking impulsive decisions. One of the important decisions that you need to make is buying the right water purifier. Though it may seem quite easy to buy a water purifier, there are a number of factors that you need to consider. The water purifier that you choose depends on the quality of water you receive in the area. In addition, you need to consider the technologies used and read the water purifier reviews before making the final decision. If you too are planning to buy the best water purifier here are some important factors you need to consider. How to choose the best water purifier for home You should consider the below mentioned points whilst purchasing a water purifier. Water Quality As already mentioned, you need to check the water quality before buying a purifier. If water in your area has a high TDS level, hardness and salinity, you need to opt for an RO water purifier. RO water purifiers come with a semi-permeable membrane which can remove the dissolved salts, metals and impurities. Types of Water Purifier There are different water purification technologies available in the market. Understanding the various water purifier technologies is very important in order to make the right decision. Depending on the water quality and budget, you can choose among RO, UV, and UF (gravity based) water purifiers. Here are some more details about the various technologies. RO Water Purifiers Reverse Osmosis Purifiers are ideal for areas that have high TDS level. RO water purifiers can remove heavy metals, Fluoride, Arsenic, and other toxic impurities from water. However, RO purifiers also remove some of the essential minerals from water which can be supplemented by mineral addition system. Gravity Based Water Purifiers UF Water Purifier for low TDS water Gravity based water purifiers are budget-friendly and don’t require power to operate. You can use gravity based water purifiers if the TDS level in your area is low. The water purifiers are ideal for removing bacteria, dust, chlorine and cysts from water. UV Water Purifiers UV Water Purifier UV water purifiers use a high power UV lamp to disinfect the water, the UV purifier does not remove other physical or chemical impurities from the water. Contamination Contaminants Present in Water Bacteria, nitrate, dissolved pesticides, and lead are some of the common contaminants present in water. The amount of contaminants present in water can be tested in any laboratory. If water supplied to your home is high in microbes and contaminants, you need to install a RO+UV+UF filtration as an intelligent choice. The UV effects irradiate the water and penetrate the cells of bacteria and viruses, destroying their ability to reproduce. These organisms fail to multiply and eventually die. The RO membrane removes these dead germs and contaminants from water and makes it fit for consumption. Storage Capacity When buying a water purifier, it is very important to take into account the storage capacity. If you live in an area which is prone to power cuts, you need a water purifier which has a higher storage capacity. The automated water purifiers start the purification process as soon as the water level in the purifier declines. Certifications Another important factor that you need to check in water purifier reviews is the certifications received by the brand. Certified water purifiers ensure that the brand is authentic and trustworthy. ISI and WQIA (Water Quality Association of India) the Indian certification bodies, NSF, WQA, IBWA etc. are International certification bodies. Maintenance and After Sales Services Lastly, before making the final decision, ensure that you get all the necessary information about maintenance and after-sales services of water purifiers. A water purifier that needs frequent maintenance services is not worth the money you invest. In addition, you also need to check the after sales services provided by the company. Poor after sales services lead to a lot of problems if something goes wrong with the water purifier.
Green Water Concepts India Pvt Ltd has signed an agreement with Kottopadam Grama Panchayat for the supply, installation, and commissioning of UV water purifiers, 500LPH capacity. GWC has successfully installed 18 nos of UV water purifiers with auto cut off facility. The purifying units consists of 1. Sediment Filter - 5 micron, 20inch, with 20inch polypropylene cartridge 2. Carbon block filter (CTO, 20') 3. Sediment Filter - 1micron, 20inch, with PP Cartridge 4. Solenoid Valve 5. UV System 500LPH - alpha UV 6. Loft Tank, 150L capacity 7. SS Taps, for dispensing the water. The UV system will cut off when the loft tank is full. The school administrative already admired the quality of the job done.
Chemistry of Iron Removal Iron is one of the most abundant metals of the Earth's crust. It occurs naturally in water in soluble form as the ferrous iron or complexed form like the ferric iron (trivalent iron: Fe3+ or precipitated as Fe(OH)3). The occurrence of iron in water can also have an industrial origin ; mining, iron and steel industry, metals corrosion, etc. In general, iron does not present a danger to human health or the environment, but it brings unpleasantness of an aesthetic and organoleptic nature. Indeed, iron gives a rust color to the water, which can stain linen, sanitary facilities or even food industry products. Iron also gives a metallic taste to water, making it unpleasant for consumption. It can also be at the origin of corrosion in drains sewers, due to the development of microorganisms, the ferro-bacteries. In aerated water, the redox potential of the water is such as it allows an oxidation of the ferrous iron in ferric iron which precipitates then in iron hydroxide, Fe(OH)3, thus allowing a natural removal of dissolved iron. 4 Fe2+ 3 O2 --> 2 Fe2O3 Fe2O3 + 3 H2O --> 2Fe(OH)3 The form of iron in water depends on the water pH and redox potential. Usually groundwater has a low oxygen content, thus a low redox potential and low pH (5.0- 6.5) Pourbaix diagram of Iron However ground waters are naturally anaerobic: so iron remains in solution and therefore it is important to remove it for a water use. The elimination of the ferrous iron, by physical-chemical way, is obtained by raising the water redox potential by oxidation thanks and this by simple ventilation. In the case of acid water, the treatment could be supplemented by a correction of the pH. Thus, the ferrous iron is oxidized in ferric iron, which precipitates in iron hydroxide, Fe (OH)3. The precipitate is then separated from water by turbidity removal filter or decantation. The stage of precipitation by chemical oxidation can also be carried out with the stronger oxidants such as sodium hypochlorite (NaOCl), chlorine dioxide (ClO2), ozone (O3) or the potassium permanganate (KMnO4). This elimination can be carried out by cascade or spraying open-air systems (for an acceptable maximum content of Fe2+ of 7mg.L-1) known as gravitating systems. Those systems require a significant place on the ground, but, in addition to an easy and a cheap exploitation cost, they also make possible aggressive CO2 and hydrogen sulfide (H2S) removal. There are also pressure systems, which in addition to their compactness, make possible to treat water whose Fe2+ concentrations between 7 and 10mg.L-1. Iron removal system schema Iron is often found in water in complexed forms. In order to be eliminated, iron complexed requests a coagulation stage, which comes in between oxidation and filtration. Remark : It is possible to remove iron from water by biological way. Indeed, there are many bacteria, whose metabolism and thus their survival, are related to the oxidation of iron. However this biological removal requires conditions specific for the pH, the temperature, the redox potential, etc.
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