When one thinks of recycling, one typically thinks of readily identifiable consumer products that are collected, sorted and re-purposed for another use. While this is a traditional perception of recycling, there are actually three basic types of recycling. These include:

Mechanical recycling - Once again, this is the traditional perception of recycling in which post-consumer or post-industrial recycled plastic is collected, sorted and re-purposed for another use

Solvent recycling – This is a relatively new approach to recycling in which plastics products are collected and sorted and then exposed to a solvent process in which contaminants, various additives and colorants are removed from the polymer. The “refreshed” polymer can then be used to manufacture a new plastic article.

Chemical recycling – Another relatively new approach but one that has gained significant interest in recent years. Chemical recycling is based on a chemical process in which the collected plastic items are collected, sorted, cleaned and then processed back to its basic chemical constituents. The exact process may vary based on the type of plastic involved or the specific chemical reactions required. However, the process results in the generation of basic chemical building blocks that can then be used to create new polymers designed for a specific purpose.

All of these recycling technologies are being investigated throughout the plastic pipe value chain. The performance requirements for plastic pipe make the concept of recycling somewhat challenging, However, where feasible, standards and industrial processes are already in place and being utilized for the mechanical recycling of post consumer recycled plastic into the production of plastic drainage pipe. ASTM F2306 in combination with AASHTO M294 established the guidelines and requirements for the use of recycled polyethylene (PE) in drainage pipe. Clearly, initiatives such as this increase the potential for fulfilling the goal of sustainability and a circular economy as it relates to plastic pipe.

ASTM F2306 establishes the guidelines and requirements for the use of recycled polyethylene (PE) in the production of HDPE drainage pipe. This innovative approach to the manufacture of HDPE drainage pipe is based on sound engineering principles and creates the opportunity for the use of up to 25% recycled PE for use in a 100-year service life applications such as roadway drainage or culverts.

PPI estimates that the market for HDPE drainage pipe currently utilizes approximately 600 million pounds of recycled resins per year. If corrugated HDPE pipe were more broadly approved to replace traditional materials, such as concrete pipe, the industry could easily utilize well over 1 billion pounds of post-consumer, single use plastics per year.

The average consumer PE bottle weighs approximately 150 grams. Thus, the 600 million pounds of recycled PE is equivalent to approximately 1.8 billion plastic bottles diverted from the waste stream and responsibly re-purposed as drainage pipe.