EREF has released a report exploring the impact of greenhouse gas (GHG) emissions and fossil energy use associated with curbside municipal solid waste (MSW) management systems.

"Life-Cycle Assessment (LCA) of Curbside Material Recovery" examines greenhouse gas emissions and fossil energy use in landfilling, recycling, and yard and food waste composting.

"When studying the environmental impacts of waste management systems, life cycle assessments (LCA) can provide valuable insight into the cycle of a product’s use, disposal, and potential re-use,” said Bryan Staley, PhD, PE, President and CEO of EREF, in a statement. “The results of EREF’s LCA of Curbside Material Recovery shines a light on the importance of understanding the trade-offs of different collection and endpoint management options."

He added that the results will assist with generating "meaningful dialogue and informed decision-making by highlighting the nuances and sensitivities that should be considered with curbside material recovery.”

By definition, the LCA technique quantifies the environmental impact of a product, process or decision, similar to a cost analysis. EREF's report analyzes the" considerations and conditions affecting the sustainability of materials recovery overall, and for specific materials, in North America."

The organization investigated three curbside MSW recovery options: single-stream recycling, yard waste composting, and mixed organics composting (i.e. food and yard waste). A landfill-only MSW management program gradually added services one by one. 

In reference to methods of waste disposal in reducing GHG emissions, landfill gas-to-energy along with recycling were the catalysts for significant reduction along with a reduction in energy demand. This assumed a bottle-to-bottle recycling system. 

"However, the end use of the recyclables are very important and sustainability benefits can be highly variable and even erased under some non-closed loop end use scenarios," the report stated. "For recyclables with marginal or highly variable emissions or energy savings, transport distance to the secondary process can become an important consideration. Emissions and energy savings were found to be different depending on the recyclable being evaluated (e.g. paper, plastic), which suggests that focusing on specific materials that offer the greatest emission reduction when recycled may leader to great overall savings."

While composting provides benefits, efforts such as backyard composting, anaerobic digestion and bioreactor landfilling could assist in lowering GHG emissions and energy demand. Aside from those, EREF stated that organics diversions activities also could have "other positive local/regional environmental impacts."

"Overall, landfilling, recycling, and composting are important components of the waste management system, but maximizing recovery and closed-loop remanufacturing of materials through recycling has the greatest potential for reducing GHG emissions and energy demand associated with curbside material recovery," the report stated.