• Contact Us|
  • Terms & Conditions|
  • Team Members
  • Products
    • Product Catalog
    • Ductile Iron Pipe
    • Request Product Information
    MJ Mechanical Joint

    View the different joints and sizes we offer for ductile iron pipe.

  • Learning Center
    • Specifications
    • Submittal Sheets
    • Installation Guides
    • Downloadable Tip Sheets
    • Iron Strong Blog
    • Training Opportunities
    • Archived Catalogs
    • Frequently Asked Questions
    • Videos
    • Pocket Engineer
    DIP Production

    We provide all the necessary product-related information to our customers.

  • Sales & Support
    • Sales Team
    • Distributors
    • Treatment Plant Sales
    • Customer Service
    • Sales Operations
    DIP MJ Joint

    Our sales team strives to exceed customer expectations every day.

  • Corporate Responsibility
    • Code of Conduct
    • Environment
    • Health & Safety
    • Community
    • Awards

    A clear vision from our leaders, places environment, health and safety at the core of our business.

  • About Us
    • Company History
    • Executive Team
    • Locations
    • Associations
    • Contact Us
    McWane Ductile Iron Pipe

    We are a proud and experienced manufacturer of ductile iron pipe products.

  • Communications
    • Publications
    • McWane News Articles
    • Press Releases
    • Media Contacts
    Ductile Iron Pipe

    We strive to keep our team members, customers, and vendors informed of all happenings at the company.

  • Careers
  • Home
  • Learning Center
  • Iron Strong Blog
  • Should A Water Utility Manager Let System Infrastructure Dictate Water Treatment Methodology?
Back to Blog

Should A Water Utility Manager Let System Infrastructure Dictate Water Treatment Methodology?

By Roy Mundy, P.E., ENV SP, Assoc. DBIA   05/22/2020  In Environmental & Safety

Providing safe, clean water to customers of a water utility is unquestionably JOB ONE. Meeting this goal has always been a formidable challenge in many ways. Source water quality can change dramatically due to weather factors and other phenomena. Additionally, increasing drinking water standards throughout the years evidencing higher detection technology and more sophisticated medical research regarding the health effects of contaminants has required water systems in some cases to change treatment methodologies dramatically.

Should the pipeline material placed in a drinking water system in any way limit decisions of today or in the future regarding the water treatment methodology chosen to best provide safe, clean water to customers? I THINK NOT!

Meeting the goal of providing cafe, clean water has always been a formidable challenge.

If We Only Knew Then What We Know Now

A recent story from Hamilton, Ohio illustrates this fact . . .  “We’ve got about 21 miles of HDPE piping in our system now, and it is catastrophically failing, about 60 years ahead of when it should have,” Logan said. “This, back about 20 years ago, was the future of water mains, and unfortunately, the chemicals we use attack the pipe and then cause it to fail. So, we’re going back to iron piping.” – City of Hamilton, Ohio Executive Director of Infrastructure Jim Logan.

The cause of these failures has been identified as the City’s use of water disinfectant. Considering disinfecting water prior to sending out to the distribution system is not an option, the choice for infrastructure integrity then becomes to use plastic pipe or not.

 We would suggest that not using plastic pipe is the better choice, especially considering the superior option of Ductile iron pipe (DI pipe). Hamilton is not entirely alone in its experience with plastics. There have been numerous other experiences with the premature failure of other plastic pipes such as Poly-B and polyethylene pipes in Canada. The use of these materials resulted in numerous lawsuits and the removal of those products from sale there.

For a comparison between Ductile iron pipe and HDPE, see this informative Iron Strong Blog by my colleague Ken Rickvalsy.

Hamilton, Ohio. Photo Source: Epic Water Filters

Water Disinfectants Can Be Corrosive to Plastic

Chlorine has been the "silver bullet" for the water industry to control disease-causing contaminants for over a century now. However, derivations of simply using free chlorine have been instituted due to potential water system components such as Trihalomethanes (THM's). Thus, a full range of options must always be available to the water utility to combat various contaminants. In the case of Hamilton, Ohio, this option was Chlorine Dioxide.

 Although the Ductile Iron pipe industry has often stated there was too much unknown about the interaction of chemicals and plastics in water system treatment and operation to make plastic a viable alternative to iron pipe; little research had been done until these types of failures started to propagate.

 Research being conducted now has shown disinfectant chemicals can have a corrosive effect on plastics in addition to the situation noted in Hamilton, Ohio. This effect could further be enhanced if systems introduce free chlorine into the water system beyond the point source application at the treatment plant.

The Issue: Oxidative Degradation

The scientific process causing these premature failures in plastic pipe products is oxidative degradation, which creates what is called Slow Crack Growth (SCG) in plastic pipelines. Slow Crack Growth occurs because the plastic's antioxidants are depleted by free chlorine, which is chlorine in the water.

“The residual disinfectant “concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide...cannot be undetectable….” - USEPA Surface Water Treatment Rule, 6/1989, 40 CFR 141.72 (b)(3)(i)

“...free chlorine is the amount of chlorine that can inactivate pathogenic microorganisms present in the water whereas total chlorine is the sum of combined chlorine and free chlorine.” -  USEPA, “Understanding Disinfection Residuals”

 There is now much research that has been conducted on disinfection and disinfectant residuals and their effects on plastic pipes, which have been listed at the end of this article.

Example of Oxidative Degradation and Slow Growth Cracks in HDPE pipe. Photo Source: DIPRA

Chemicals Negatively Affect Plastic Pipes

The short version is this; chemicals negatively affect the life and performance of plastic pipes through the formation and growth of cracks in the exposed pipe surface because the surface becomes brittle. It is also noted that this phenomenon occurs at a greater pace in warmer areas, so southern utilities will likely experience shorter life expectancy than northern utilities.

 While the research is still young, it is reasonable to project that, with the surface cracking, more plastic surface is exposed via the crack depth, resulting in faster corrosion/degradation rates. Faster corrosion/degradation rates cause the cracks to widen and deepen, leading to pipe failure in much less than the 50- to 60-year design life.

 This research has been primarily focused on oxidative degradation. Research has not focused on the potential for chemicals leaching into drinking water, at what concentrations, and the subsequent health effects of this leaching.

You might consider that, by using other types of plastic pipes such as Polyvinyl chloride (PVC), this would not be a concern, but current research shows the propensity for Slow Crack Growth in PVC as well as HDPE with the difference being slower growth rates of the cracks.

However, considering the greater rigidity of PVC compared to HDPE, it is no surprise that PVC failures show up as long, catastrophic cracks, particularly in long lengths of fused PVC.

Providing safe, clean drinking water is JOB ONE of the utility.

JOB ONE is Water Safety – Go Ductile Iron

A water utility must always have the flexibility to address JOB ONE of the utility ─ providing safe, clean water to customers. Restricting the use of applicable water treatment methodologies to address both current and future drinking water standards due to certain materials utilized in the water system for pipelines is clearly putting the cart before the horse when it comes to the utility's priorities. See another Iron Strong blog about ensuring safe drinking water by my colleague, Jerry Regula.

Having sat in the seat of a water company manager for over three decades, I very much appreciate the transparency of the water utility leadership in Hamilton, Ohio, to be forthcoming to their customers about the problem they are now facing. Without question, different decisions would have been made in the past if today's information were known then.

Hopefully, now that science is proven regarding the failure of HDPE in this circumstance, water utilities can plan accordingly. Planning can include selecting pipeline materials for transmission and distribution pipelines that are not subject to oxidative degradation and have not been for centuries of use, such as IRON PIPE, and in today's world, DUCTILE IRON PIPE.

For further information on how disinfectants affect pipe life and performance (or don’t in the case of McWane Ductile Iron Pipe), please contact one of our Sales Representatives, Regional Engineers, or Product Engineers.

Subscribe to the Iron Strong Blog

Need Assistance with Your Waterworks Project?

We have team members who’ve managed small and large water utility systems, served in engineering consulting firms, and bring decades of experience in solving field issues involving pipeline construction and operation. From design, to submittal, to installation, we strive to provide education and assistance to water professionals throughout the water and wastewater industry.

Check Out All Our Digital Offerings

  • More articles and videos from our Iron Strong Blog
  • The McWane Pocket Engineer
  • Engage with us on LinkedIn
  • Follow us on Facebook
  • Follow us on Twitter

Appendix:

  • USEPA, “Understanding Disinfection Residuals”
  • USEPA, “The Effectiveness of Disinfectant Residuals in the Distribution System”
  • TCEQ, “Disinfectant Residual Reporting for Public Water Systems” Dear, J. P. and Mason, N.S., “The Effects of Chlorine Depletion of Antioxidants in Polyethylene,” Polymers and Polymer Composites, Vol 9, No. 1, 2001.
  • Duvall, D. and Edwards, D., “Oxidative Degradation of High-Density Polyethylene Pipes from Exposure to Drinking Water Disinfectants,” Engineering Systems Inc., December 18, 2009.
  • “Is PE resistant to the chemicals commonly used for disinfection, e.g. chlorine?”, PE100+ Association, May 29, 2018, Online Article, accessed March 10, 2020.
  • Colin, X., et al, “Aging of Polyethylene Pipes Transporting Drinking Water Disinfected by Chlorine Dioxide. Part II – Lifetime Prediction,” Polymer Engineering and Science, 2009.
  • Jerry Eng, Thomas Sassi, Thomas Steele, Giacomo Vita, Cytec Industries, “The Effects of Chlorinated Water on Polyethylene Pipes”
  • Susan M.Mitroka, Timothy D. Smiley, J.M. Tanko, Andrea M.Dietrich, “Reaction mechanism for oxidation and degradation of high-density polyethylene in chlorinated water”  

Share on social media

  • Print this Article

Roy Mundy, P.E., ENV SP, Assoc. DBIA

Roy Mundy, P.E., ENV SP, Assoc. DBIA, currently serves as Senior Regional Engineer for McWane Ductile, assisting utilities and engineering firms with value engineering of pipeline projects, education in pipeline material selection, and providing assistance with specification development and updating. Roy has a BS in Civil Engineering from West Virginia Institute of Technology; MS in Engineering Management West Virginia University College of Graduate Studies; and is a Registered Professional Engineer in six states; ENVISION Sustainability Professional. Prior to McWane Ductile, Roy served as Lead Executive with the American Water System, retiring as President/CEO of Kentucky-American Water Co. Roy has served as Section Chair and is on several national committees of AWWA, Board of Directors and national committees of NAWC, Chair of ORSANCO, member of Kentucky Infrastructure Authority. He is currently serving on AWWA – Business Practices Standards Committee, the KY/TN Section Management Committee, and the Water/Wastewater and Legislative Committees of DBIA. Roy is a member of AWWA, NSPE, KSPE, ASCE, DBIA, and KYRWA.

"I joined McWane Ductile 5 years ago after spending most of my career in the water industry in the private water utility sector," said Mundy. "I enjoy the opportunity to work with engineering firms and utilities in assisting with value engineering projects and providing education on aspects of our products. I enjoy restoring classic cars, but foremost enjoy time with my family traveling and working around our small farm in Kentucky."

roy.mundy@mcwaneductile.com

https://www.linkedin.com/in/roy-mundy-7b42417/

  • Learning Center
  • Specifications
  • Submittal Sheets
  • Installation Guides
  • Downloadable Tip Sheets
  • Iron Strong Blog
  • Training Opportunities
  • Archived Catalogs
  • Frequently Asked Questions
  • Videos
  • Pocket Engineer
  • Blog
  • Categories
  • Environmental & Safety
  • Installation
  • Our Company
  • Products
  • Services
  • Technical

Careers

Apply or view job opportunities

Search Careers

McWane Pocket Engineer

McWane Pocket Engineer

The one tool you never want to be without

Learn More

Buy American

Your trusted provider of guaranteed American-made waterworks products.

Learn More

Recognized as a proud member

  • ISI Member
  • DIPRA Logo
  • American Water Works Association
  • Water and Sewer Distributors of American WASDA
  • National Association of Water Companies
  • Water Environment Federation WEF
  • Products|
  • Learning Center|
  • Sales & Support|
  • Corporate Responsibility|
  • About Us|
  • Communications|
  • Careers

McWane Corporate

  • About|
  • Our Businesses|
  • Responsibility|
  • Environment|
  • Safe Operations|
  • Communications|
  • Careers|
  • Multimedia Library
Learn about McWane’s Environmental Focus

© 2021 McWane Ductile. All rights reserved

Privacy Policy | California Privacy Notice | Terms & Conditions | California Transparency in Supply Chain Disclosure | Sitemap | Contact Us

  • Products
  • Product Catalog
  • Ductile Iron Pipe
  • Request Product Information
  • Learning Center
  • Specifications
  • Submittal Sheets
  • Installation Guides
  • Downloadable Tip Sheets
  • Iron Strong Blog
  • Training Opportunities
  • Archived Catalogs
  • Frequently Asked Questions
  • Videos
  • Pocket Engineer
  • Sales & Support
  • Sales Team
  • Distributors
  • Treatment Plant Sales
  • Customer Service
  • Sales Operations
  • Corporate Responsibility
  • Code of Conduct
  • Environment
    • Protecting the Environment
      • Our Environmental Legacy
      • Investments
      • Environmental Management System
      • ISO & State Certifications
      • Environmental Excellence
      • Pollution Prevention Challenge
    • Sustainability for Generations
      • Sustainable Products
      • Sustainable Operations
  • Health & Safety
    • Culture of Safety
    • EHS Policy
    • McWane EHS Program
    • Ergo Cup
    • ISN & Contractor Safety
    • EHS Awards
  • Community
    • McWane Commitment
    • Partnerships
    • Community Advisory Panel
    • Charitable Giving Guidelines
  • Awards
  • About Us
  • Company History
  • Executive Team
  • Locations
  • Associations
  • Publications
  • Contact Us
  • Communications
  • McWane News Articles
  • Press Releases
  • Media Contacts
  • Careers
  • Team Members