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'Research never ends'

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Philip Singer" a professor in the Gillings School of Global Public Health directs UNC-Chapel Hill?s Drinking Water Research Center.For more than 30 years Singer?s work has focused on improving drinking water quality by finding ways to reduce cancerous disinfection by-products.

Next time you take a sip from the Old Well thank Philip Singer.

Singer who directs UNC's Drinking Water Research Center and is also a professor in the Gillings School of Global Public Health has been working for 35 years to improve drinking water quality in Chapel Hill and across the nation.

Singer's drinking water work covers lots of areas. But predominantly he focuses on minimizing exposure to substances called disinfection by-products. Here's why:

In 1974 it was observed that chlorine which is used by utility companies to disinfect water reacts with naturally occurring organic matter like algae and twigs to form a number of disinfection by-products — or compounds resulting from this reaction.

Scientists found these by-products also known as DBPs to be cancerous. Since then more DBPs continue to be discovered. For the past 35 years they have been the most pervasive issue in the field of drinking water research.

Regulations from local agencies as well as federal agencies like the Environmental Protection Agency have been in place since 1979 to help lower DBP concentrations to keep consumers safe.

Various methods of DBP reduction are done in different parts of the country but Singer says the South is particularly problematic.

Chlorine reacts with natural materials and since the South is abundant in materials like these the water is too. This causes the water as soon as it goes through treatment and receives chlorine to aid in disinfection" to contain DBPs and endanger consumers.

""It's an interesting balance" because on the one hand you have to disinfect the water but on the other hand you get disinfection by-products after cleaning the water that could be harmful" Singer said. It's a trade-off and a risk.""

Singer's research" which has been going on since the DBP discovery in 1974 and has received about $11.5 million in funding eases this risk.

There are five broad stages that water treatment plants use to purify water. In the first stage called coagulation dirt and other particles suspended in the water are removed. Singer's research confirms that coagulation effectively reduces DBP precursors like the natural materials.

One of the main focuses of Singer's coagulation research which began in 1976 is the enhancement of the coagulation process to remove DBP precursors altogether.

Thanks to Singer's research" the EPA has identified coagulation as one of the best available technologies for controlling DBPs and a necessary safeguard for clean drinking water.

""Because we know that coagulation can lead to the removal of substantial amounts of these precursors" the big advantage is that now most utility companies apply chlorine after sedimentation and coagulation Singer said. And because there's less organic material in the water" less DBPs are formed.""

This means that because coagulation helps rid our water of natural materials before the chlorine is applied to disinfect it"" the chance of disinfection by-products entering our water is significantly reduced.

Singer says that coagulation's best feature is that it is relatively inexpensive — a necessary attribute in a country where water is significantly underpriced.

""If anybody sits down and looks at their utility bills" they'll find that water is less than cable telephone Internet. And water is an essential part of life said Singer.

Singer hopes to create more effective processes for removing organic material from water.

He is now studying an in-depth process called anion exchange" another way to remove organic material. Anion exchange would prevent the organic material from coming into contact with chlorine, thus eliminating DBPs.

Anion exchange would also help reduce amounts of the element bromide in water. When bromide, found naturally in water, comes into contact with chlorine, a more harmful disinfection by-product is created — one that is potentially more cancerous.

Overall, Singer said, he wants to prevent people from coming into contact with DBPs without compromising disinfection.

He has been successful.

Over the course of 35 years" we have lowered exposure to disinfection by-products 50- to 100-fold" he said.

But he's not quite done. Singer said that even after 35 years of making our drinking water clean, he plans to keep finding ways to make water safe for everyone.

Research never ends.""



Contact the University Editor at udesk@unc.edu.


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