- Case Studies
Industry: construction material production
Project Type: environmental label development and energy efficiency
Location: Portland, OR
Anika Sarkar interned with Knife River Corporation to create Environmental Product Declarations for their concrete mixes and develop energy efficiency and waste reduction strategies.
Knife River Corporation is the fifth largest sand and gravel producer in the U.S. They also market construction materials, including ready-mix concrete, cement, asphalt, and other value-added products. In 2017, Knife River Corporation produced 3.5 million cubic yards of concrete from a total of 90 locations. About 5 percent of this concrete is returned to plants due to over ordering. Although some of the returned concrete is repurposed, the process is energy intensive, and some concrete is also lost to waste.
Environmental Product Declarations (EPDs) are labels that disclose environmental impacts, such as energy and water use, associated with the manufacturing, allowing customers to select lower impact products. EPDs have become a market driver in Oregon following the new Leadership in Energy and Environmental Design (LEED) green building rating protocols, which award points for EPDs in construction projects.
Using life cycle analysis concepts and an inventory process, Sarkar helped to create EPDs for 479 concrete mixes across four plants. The EPD analysis results indicate that cement production contributes approximately 85% of the total global warming potential for concrete mixes.
The intern found that a mechanical concrete reclaimer, which is able to separate aggregates and grey water (slurry composed of cement and water), would solve the problem of handling concrete returns, increasing the amount of returned product that can be reused.
Sarkar also connected Knife River with the Energy Efficiency Center at Oregon State University (OSU) who conducted an Industrial Energy Assessment at one facility. She also found that the National Ready Mixed Concrete Association (NRMCA) offers certifications that drive continual environmental improvement.
The EPD labels will enable Knife River to identify production ‘hot spots’ that, once addressed, can improve the company's environmental performance. EPDs also help consumers to select lower impact concrete mixes, and help the company meet LEED standards.
Following Sarkar's recommendations, a mechanical concrete reclaimer has been installed at one plant, with a possible roll out to other locations, if it is successful.
The pollution prevention assessment conducted by Sarkar and OSU's Industrial Energy Assessment identified areas for energy savings and production process improvement. The assessment recommendations could result in an annual energy savings of approximately 1,500 million British Thermal Units (mmBTU), saving Knife River $30,000 per year after a one-year return on investment, if adopted.
To further Knife River’s environmental goals, the intern recommended that the company pursue NRMCA's Green-Star Certification.
Environmental Product Declarations
per year in potential savings
mmBTUs potential reduction per year