Shining the Light on Clean Water Systems Design: How UV Technology Protects Our Drinking Water

Shining the Light on Clean Water Systems Design: How UV Technology Protects Our Drinking Water

For many decades, the production of drinking water was synonymous with using multiple chemicals to remove contaminants and render it free of germs and viruses that cause us to get sick. When I started at HDR 16 years ago, several of my first projects were to design large chlorine gas and sodium hypochlorite (liquid bleach) systems to disinfect river water. While such systems made the water safe for consumers, the use of these systems is actually quite hazardous to workers. Thankfully, I’ve never been in a chemical accident, but I have seen the aftermath of bleach spills and heard enough stories about gas leaks to know that water disinfection was a dangerous task.

Fortunately, the science of industry has advanced considerably with the development of reliable systems based on ultraviolet (UV) light. Now, compact, chemical-free systems are used to disinfect for Cryptosporidium, Giardia, and other pathogens. I believe that UV disinfection is one of those wonderful technological breakthroughs in the water industry where the end product is cheaper, safer, and even more effective that the chemicals that it replaced. The widespread use of these new systems is due in large part to HDR. Our Water Institute has been on the forefront in developing these systems at the Technology Validation Center in Johnston, NY. 

There, our institute’s expert staff of engineers and scientists has been instrumental in developing and validating hundreds of these systems for commercial drinking water applications, as well as, municipal wastewater and even industrial uses. Combining our in-depth knowledge of these processes, along with our world-class design expertise, has allowed us to help multiple utilities worldwide integrate these UV systems into new and existing infrastructure to ultimately produce better water.

Currently UV technology has progressed beyond pathogen destruction to its use in advanced oxidation processes (AOPs). When UV is combined with peroxide, ozone, or even chlorine, the resulting combination of processes is able to destroy trace contaminants that each of these processes performed individually would be unable to affect. UV/AOPs are broad-spectrum barriers to pesticides, algal toxins, and endocrine-disrupting compounds, contaminants that pose an ever-greater concern for drinking water utilities. In addition, UV/AOP is often one of the key steps in both direct and indirect potable reuses, where its ability to cost-effectively destroy compounds of emerging concerns and it’s use in pharmaceutical and personal care products, is generally required by regulatory agencies. 

Even if not needed now, my colleagues and I have successfully helped clients procure and install UV equipment that can be readily upgraded to include  AOP capabilities, if and when the additional treatment is required. By adding a little additional room for piping, power cabinets, and chemical feed systems, we can provide systems installed for 2- or 3-log Cryptosporidium inactivation that can be upgraded to 6+ logs and provide the end-user greater flexibility than simply meeting today’s regulations.

I believe that UV disinfection in the water industry is one of those wonderful technological breakthroughs where the end product is cheaper, safer, and even more effective than the chemicals it has replaced. Its proven track record is the reason it has progressed from a system that is optional or needed for very specific applications, to being installed, or at least master planned, as general best practice. I’m proud of that we continue to be at the forefront of this technology, with our on-going work at the Technology Validation Center. These experts continue to  push newer UV systems and our award-winning design capabilities to use these systems to meet our client’s needs. The future of UV technologies shines brightly and we’re here to help light the path forward.

Pierre Kwan
Water Treatment Technical Director