- Water Problems
The process of osmosis through semipermeable membranes was first observed in 1748 by Jean-Antoine Nollet. For the following 200 years, osmosis was only a phenomenon observed in the laboratory. In 1950, the University of California at Los Angeles first investigated desalination of seawater using semipermeable membranes. Researchers from both University of California at Los Angeles and the University of Florida successfully produced fresh water from seawater in the mid-1950s, but the flux was too low to be commercially viable until the discovery at University of California at Los Angeles by Sidney Loeb and Srinivasa Sourirajan at the National Research Council of Canada, Ottawa, of techniques for making asymmetric membranes characterized by an effectively thin "skin" layer supported atop a highly porous and much thicker substrate region of the membrane. John Cadotte discovered that membranes with particularly high flux and low salt passage could be made by interfacial polymerization of m-phenylene diamine and trimesoyl chloride. Cadotte's patent on this process was the subject of litigation and has since expired. Almost all commercial reverse osmosis membrane is now made by this method. By the end of 2001, about 15,200 desalination plants were in operation or in the planning stages, worldwide, with approximately 20 percent of them in the U.S., the largest number of any country in the world.In terms of capacity however, the U.S. ranks second globally Reverse osmosis production train, North Cape Coral Reverse Osmosis Plant.
In 1977 Cape Coral, Florida became the first municipality in the United States to use the RO process on a large scale with an initial operating capacity of 3 million gallons (11350 m³) per day. By 1985, due to the rapid growth in population of Cape Coral, the city had the largest low pressure reverse osmosis plant in the world, capable of producing 15 million gallons per day (MGD) (56800 m³/d).
Although Reverse Osmosis seems like a complex system it is really a simple and straightforward water filtration process. And it’s not a new process. High-pressure (pump driven) reverse osmosis systems have been used for years to desalinate* water – to convert brackish or seawater to drinking water. Having a better understanding of how a reverse osmosis system works will eliminate the mystery and confusion you may feel when you look at a reverse osmosis system with its many colored tubes and multitude of filters. Read on to enhance your knowledge of residential reverse osmosis systems.
In 1878, Arthur Downes and Thomas P. Blunt published a paper describing the sterilization of bacteria exposed to short-wavelength light. Ultraviolet (UV) has been a known mutagen at the cellular level for over 100 years. The 1903 Nobel Prize for Medicine was awarded to Niels Finsen for his use of UV against lupus vulgaris, tuberculosis of the skin.
Using UV light for disinfection of drinking water dates back to 1910 in Marseille, France.The prototype plant was shut down after a short time due to poor reliability. In 1955, UV water treatment systems were applied in Austria and Switzerland; by 1985 about 1,500 plants were employed in Europe. In 1998 it was discovered that protozoa such as cryptosporidium and giardia were more vulnerable to UV light than previously thought; this opened the way to wide-scale use of UV water treatment in North America. By 2001, over 6,000 UV water treatment plants were operating in Europe.
Over time, UV costs have declined as researchers develop and use new UV methods to disinfect water and wastewater. Currently, several countries have developed regulations that allow systems to disinfect their drinking water supplies with Ultraviolet (UV) light.
Ultraviolet or “UV” is a type of energy found in the electromagnetic spectrum, lying between x-rays and visible light. Although we cannot see UV light or rays, we are exposed to them every time we step out into the sun. In fact, UV light is responsible for causing sunburns.
UV Water Purification systems use special lamps that emit UV light of a particular wavelength that have the ability, based on their length, to disrupt the DNA of micro-organisms. These UV light waves are also referred to as the Germicidal Spectrum or Frequency. The frequency used in killing micro-organisms is 254 nanometers (nm). As water passes through a UV water treatment system, living organisms in water are exposed to UV light which attacks the genetic code of the microorganism and rearranges the DNA /RNA, eliminating the microorganism's ability to function and reproduce. If a microorganism can no longer reproduce, it cannot replicate, therefore it cannot infect other organisms with which it has contact. This process of exposing water to UV light is simple but effective, destroying 99.99 percent of harmful microorganisms without adding any chemicals to water.
Many water purification systems take advantage of a UV water sterilizer even after processing their water. This is a well-known practice. Companies like Puritech highly recommend UV sterilizers as a post treatment when treating water. Throughout the years ultraviolet technology has become well established as a chosen method for effective and economical water disinfection. Ultraviolet water sterilization claims many advantages: All microorganisms are virtually susceptible to ultraviolet disinfection. For every penny of operating cost, hundreds of gallons of water are purified. NO additional chemicals are added and there’s no danger of overdosing. Once the water leaves the purifier, it is ready for use with no further contact time required. It has simple and easy to install and maintain. Compact units need a small space to operate and store. Ultraviolet water sterilizers deliver ongoing disinfection without special attention or measurement. There are no detections of chlorine taste or corrosion problems.
Early water treatment methods still used included sand filtration and chlorination. The first documented use of sand filters to purify the water supply dates to 1804, when the owner of a bleachery in Paisley, Scotland, John Gibb, installed an experimental filter, selling his unwanted surplus to the public. This method was refined in the following two decades, and it culminated in the first treated public water supply in the world, installed by the Chelsea Waterworks Company in London in 1829.
Further information: History of water supply and sanitation
As people become increasingly aware of the benefits of purified water, the demand for equipment capable of treating both municipal and well water supplies continues to grow. As a result, Industrial/commercial Reverse Osmosis systems are becoming widely accepted. We carry a wide variety of RO systems, one of which will fit your application and your budget.
Reverse osmosis (RO), also known as hyper filtration, is used by our Commercial & Industrial Brackish Water & Seawater Reverse Osmosis Systems to purify water by removing salts and other impurities. It is also capable of rejecting bacteria, sugars, proteins, particles, dyes, and other constituents that have a molecular weight of greater than 150-250 daltons.
Major equipments of WATER TREATMENT PLANT (FOR DRINKING ) and their activities