During the disinfection process, water will pass through the 56 UV units, each of which contains 144 low-pressure, high-output ultraviolet lamps that produce 40 millijoules per square centimeter of light that together can treat an average of 1.3 billion gallons (4.9 billion liters) of water daily (pdf). The lamps are similar to fluorescent bulbs, but without the phosphor coating designed to protect people from prolonged exposure to UV rays.
Based on the city's specifications (pdf), the facility will use no more than 6.3 megawatts of power when the water is at the maximum flow of 2.4 billion gallons per day. (On normal days, when only 1.3 billion gallons. or liters, are flowing, energy usage should not exceed 4.45 megawatts.)
New York City is not the only city planning to use UV rays to purify its water. San Francisco's Tesla Portal drinking water facility earlier this month awarded a $5-million contract to Pittsburgh's Calgon Carbon Corp. to begin installing 12 of its Sentinel Chevron 48 UV reactors to treat up to 320 million gallons (11.5 million liters) of water daily.
There's a strong need for expanded use of technology that can clean water without the use of chemicals, says Thomas Harmon, an associate engineering professor at the University of California, Merced, and co-founder of the Center for Embedded Network Sensing (CENS), a research group that specializes in using wireless sensors to, among other things, measure and monitor water pollution. "Our water sources have become more and more vulnerable because our population has grown and sprawled out of the city," he says. "We no longer have the pristine reservoirs out on the edges of town, making it difficult to keep our source water clean."
New York's Catskill and Delaware watersheds do not require significant filtration. (They are able to shed most of their naturally occurring minerals as the water flows through the thousands of miles of pipes, aqueducts and tunnels on its way to the city's taps.) But other water sources require more than UV radiation and chlorine to make them potable. Sionix, an Anaheim, Calif.–based corporation, which manufactures a treatment system that uses microscopic air bubbles to clean water, is testing whether its technology can also reduce levels of metal, namely iron and manganese (both toxic to the body in large amounts) in Santiago Creek near Villa Park Dam in Orange County, Calif.
The creek's water has yet to be tapped for drinking water, which means it would be a new source for the surrounding communities, says Sionix CEO Jim Houtz, who adds that his company also does UV disinfection.
The Sionix Elixir system uses pressurized air that produces microscopic bubbles that adhere to suspended particles in water. The bubbles force the particles to the surface, where the system skims them out into a separate hopper. The system removes particles and parasitic organisms as small as one micron in diameter, Houtz says. (A micron is one millionth of a meter, or about four one hundred-thousandths of an inch.)
Sionix by the end of this month plans to ship a $2-million Elixir treatment system to Little Rock, Ark.–based Innovated Water Equipment, Inc., which works with oil drilling companies. Innovated Water plans to use Elixir to treat the brine water discharge from oil wells—either for reuse or to be returned safely to the environment.
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Add CommentWhat about Ozon? It is easy to generate and does not need the regular cleaning the light bulbs need. If pure Oxygen is used as the feed for Ozone, nitrous oxides generated as bi-products can be eliminated.
Reply | Report Abuse | Link to this"The Big Apple wants to use the sun's power to provide clean drinking water" implies that the plant will be solar powered-but there's no indication of that in DEP's plan, or anywhere else in this article.
Reply | Report Abuse | Link to thisAlso, Jason Cerny says "If you leave a pan of water out, UV rays from the light will clean it. We've just increased the scale, added a more efficient source of UV, and more power." But, since they won't be using sunlight, they're opting for a less efficient source of UV. Strike two. If they really wanted efficient, they'd concentrate sunlight. Problem is that the sun doesn't shine every time someone in NYC flushes a toilet.
Let's see if the project could be solar-powered:
Average power consumed will be about 4MW, which would take a 30MW-capacity PV plant to run, which would fit in about 0.15 square kilometers, or 37 acres. That would fit in the 153-acre property.
UV radiation from energy derived from electricity produced from non renewable resources just exchanges one serious environmental impact for another (toxic chemicals to global warming). Not such a clever idea. Powered by PV cells? - a much better option.
Reply | Report Abuse | Link to thisAll projects of this nature need to consider the life cycle impacts of the technology. Chlorine produced from salt to chlorinate water, may have a lesser impact than the production of UV lights, operation of the lights, and disposal at the end of their life, together with climate change impacts of energy use.
Actually, people have done environmental assessments on UV technology versus other technologies like ozone and chlorine. For example, the City of Palo Alto did a study for their wastewater treatment plant and found UV to be a better solution. The energy required to transport all the raw materials for chorine production and energy used for chlorine production has a more negative impact on the environment. This is also true for ozone. Also, the trend to move away from chlorine is due to chlorine-resistant organisms like Cryptosporidium and Giardia. These organisms are easily inactivated by UV compared to chlorine.
Reply | Report Abuse | Link to thisI have to admit I am skeptical about the UV technique. Over ten years ago I worked for a company that tried to develop this technology. After years of research they gave it up because they found that, while the UV killed something like 99% of the types of microbes, it did not kill some of the most common and most harmful ones. According to the people I talked to, the use of UV did not even reduce the amount of chlorine needed. After carefully looking over the article, I notice that there is no claim anywhere that the need for chorine is eliminated or even reduced. I cannot help wondering if these installations actually do something better or if the companies making them just have good salespeople.
Reply | Report Abuse | Link to thisI found this article misleading and inaccurate. Having more than 40 years of wide ranging experience in drinking water quality, disinfection, and environmental health with the World Health Organization/Pan American Health Organization, Global Environmental Monitoring, and the U. S. Public Health Service, I feel qualified to comment.
Reply | Report Abuse | Link to thisThe article implies that chemicals should be done away with in water treatment. This simply is not feasible. They are essential for treatment of almost all surface water supplies and even some groundwater supplies.
Ultraviolet light (UV) is very effective in killing or inactivating waterborne pathogens but it cannot completely replace chlorination as a method of disinfecting water. The article fails to mention that the New York water system will be using a combination of UV and chlorine disinfection. EPA rules require systems utilizing surface water to maintain a sufficient residual level of chlorine to help protect treated water all the way to the tap. This is necessary for several reasons when primary disinfection is accomplished by ultraviolet light.
Even though the UV will kill pathogenic microbes passing through the UV unit, it has absolutely no effect on pathogens that enter the system subsequent to the UV exposure. There is considerable potential for pathogenic organisms to enter an aging water distribution system (such as serves New York) during drops in pressure or during ruptures and repairs, or even through clandestine cross connections to a contaminated water source.
Also UV does not preclude re-growth of organisms that might pass through the UV units due to weak or burned out UV lamps, build up of deposits on the quartz sleeves, or otherwise causes of inadequate exposure. I have personally investigated facilities that relied only upon UV disinfection and found pathogenic re-contamination or re-growth no more than a few meters past the UV units.
The article also implies that chlorination causes cancer. The reality is that it is high doses of some of the disinfection by products that might possibly cause cancer but when kept below the levels set by EPA standards, which have incorporated ample safety factors, there is very low risk that there will be such a deleterious effect. The levels should of course be kept as low as possible, but it is imperative to balance the risk of proven microbial infection with the theoretical risk of cancer when dealing with drinking water disinfection.
New York City should be commended for the combination of UV disinfection and chlorination to assure the safety of its drinking water. Fred M. Reiff
dear Mr. Reiff, you have good knowledge of UV and drinking water. pls dont mind if my question sound stupid to you. My qustion is "is it harmful in any respect to drink water directly from a water filter using UV for sterallizaion". i have heard that one should wait for few minutes and keep the water treated with UV in some shady place before drinking it. Riaz Layman
Reply | Report Abuse | Link to thisThe municipal swimming pool in Redding, Calif. uses UV to disinfect the water. It's a lovely experience to swim in this silky, non-smelly water.
Reply | Report Abuse | Link to thisthats bull about fluoride preventing tooth decay! That has never been proven and on the contrary people who live in countries whose water is not fluoridated they have healthier teeth and less cavities. for a scientific website you sure are misleading people with your statement about fluoride. im not even a scientist but have done enough research to know what you claim is bull. i do agree tho however that uv light is very helpful in removing the bacteria found in water.
Reply | Report Abuse | Link to thisfluoride does not prevent tooth decay! for a scientific web blog you sure are misleading people with that statement. in fact fluoride is the main ingredient in RAT POISON! It causes nuerilogical disorders, bone cancer and cancers of many kinds and organ faulure as it effects every organ thruout the entire body! want realistic proof. check this link for the material saftey data sheet and other factual info about fluoride here... http://www.infowars.com/poison-tap-water/
Reply | Report Abuse | Link to thisThe New York market, god of the New York Times, which, in turn is the bible of democracy in this city, espouse ideologues of Panama, which considered similar to that humans drink it: the to run of the fresh waters of the rivers of Panama, under the free, UV rays from the sun, 10 hours every day.
Reply | Report Abuse | Link to thisThat is, they consider boats spend by the Panama Canal, the only alternative that justifies the investment for retaining 2 billion gallons per day of water from rivers in Panama. For them, use as Larry report, for the people of Panama, or to generate electricity, is the same as leaving the water running to the sea.
No wonder, that this bible does not want to inform the world of the "OCEANOGENIC POWER" discovered in Panama by us, or, ¿Is it because this discovery is capable of removing the profitable news generated by the global economic crisis and climate change , by solving the world's thirst for energy and clean water?