common fallacy is that all plastics are bad for the environment. Another common fallacy is that all plastics are disposable, because the first thing most people think of when they hear “plastics” is what we would consider single-use plastics such as plastic bags, bottle holders, plastic cups and other similar products that often end up in landfills or in our oceans, taking many years before they degrade. But those very properties are also found in the plastics that have been used to protect our environment.
We should not demonize and remove such a versatile material as plastics from any conversation regarding our environment. Plastics have been used for decades to protect our environment. Geosynthetics, a class of plastics used to stabilize the terrain and solve numerous civil engineering problems, are one example. Geosynthetics have been used in landfills as a means for containment, protection, separation and filtering. Without these materials, leachate generated from water seeping into a landfill can get into our groundwater, ruining ecosystems and our drinking water.
Plastics can also be used as a construction material for other essential infrastructure such as piping for water, wastewater and gas systems. This article provides the environmental argument for using plastics as a piping solution, including performance and durability, life cycle assessments and their true costs compared with other materials and recyclability.

The problem with infrastructure development often comes down to upfront cost. How can lawmakers create solutions that not only solve our infrastructure problems, but also remain cost-effective in the long term? With HDPE, highly durable and long-lasting piping systems can be created that not only last for 100 years, but also require very little maintenance. But exactly how does HDPE stack up to competing piping materials?

It is also important to mention that due to their nonreactive surfaces, HDPE piping systems do not corrode, rust, rot, pit, tuberculate or support biological growth. These properties make the material ideal for long-term projects such as wastewater systems because it does not need to be replaced or maintained in the same manner as other materials. Another benefit is that piping systems made with HDPE cost less energy to operate. In the water flow equation, the water velocity is affected by several variables including the roughness coefficient, denoted as C, which refers to the smoothness of the inner surfaces of the pipe.
New pipes typically start with a very high C coefficient — supporting high flow rates — but that number decreases as the pipe deteriorates. One form of deterioration is tuberculation, which occurs as pitting corrosion products buildup. While some materials like steel can be affected by tuberculation, with its C coefficient decreasing by more than half in about 50 years, HDPE pipes are unaffected (4).
But what happens once the pipe has reached its end of service? How recyclable is HDPE?

Another important point to make is the versatility of HDPE pipes. For example, over the last few decades HDPE pipes have been entering new markets such as gas distribution. Today, many gas lines are being converted to HDPE to help reduce leaks and improve long-term performance.
From landfill liners to highly durable pipes that keep sewage within the system until it can be treated, it should be clear that HDPE has become an essential material in protecting our environment. HDPE as a piping material is beginning to gain traction in the United States, but it is still far from the most popular option. But with time and effort dispelling misconceptions about plastics in general, it is possible that HDPE will become an ideal choice for most future piping solutions.
- Infrastructure Report Card. https://infrastructurereportcard.org/infrastructure-categories/.
- M. Najafi, A. Habibian, and V. F. Sever, “Durability and Reliability of Large Diameter HDPE Pipe for Water Main Applications.” Water Research Foundation. (2015). Accessed online 23 June 2021. https://www.waterrf.org/system/files/resource/2019-07/4485_1.pdf.
- Lifecycle Assessment of North American Stormwater Pipe Systems. https://plasticpipe.org/pdf/tr-53-2021.pdf.
- G. Maingi, “High-Density Polyethylene (HDPE) as a Replacement Material for Carbon Steel Pipes in Geothermal Projects.” KenGen. (2017). http://pubs.geothermal-library.org/lib/grc/1033763.pdf.