Published May 7, 2019

Construction and demolition debris (CDD)—or the solid waste generated by construction and demolition projects—represents a significant portion of total solid waste flow in the United States. Each year, CDD disposal facilities receive between 230 and 530 million metric tons of waste, primarily materials like concrete, wood, metal, asphalt, drywall, masonry products, and land-clearing debris (e.g., tree stumps or rocks). Managing these quantities of debris is a huge task, and there are environmental and health risks associated with the process. Common problems include odor issues, landfill fires, and leachate leaks that can impact groundwater quality.

Sustainable materials management, or a systemic approach to using and reusing materials more productively over their entire life cycles, can alleviate certain risks by diverting waste from landfills. Materials recovery is an important aspect of that, and CDD recovery is a promising avenue for economic, environmental, and social benefits.

EPA researchers support sustainable materials management planning by providing practitioners with information, guidance, and tools. EPA’s waste management research portfolio works to meet the needs of a broad range of stakeholders, but it can be difficult for individuals to locate the information they need. A recently released EPA report, “Sustainable Materials Management Options for Construction and Demolition Debris,” summarizes five years’ worth of CDD research to help practitioners, regulators, and other stakeholders find information on research relevant to them. The research topics range from best management practices for reducing odor issues at landfills to improving life-cycle analysis for waste materials, and can inform decision-making at national, regional, and local levels.

The report highlights a “methodology” to estimate the quantity, composition, and management of CDD in the United States, which offers improved estimates of nationwide CDD generation. Although EPA has tracked and estimated municipal solid waste flows for more than 30 years, until recently, CDD estimates were not included.

Historically, few states have reported CDD data, and the few estimates that were made were done using a materials flow analysis approach. These estimates were low and did not typically include debris generated by large infrastructure projects like construction and demolition of roads, bridges, and airports. Now, several states do track and report CDD generation. The newly developed method of estimating CDD generation incorporates these reported measurements and extrapolates the rest from indicators such as the number of building permits issued, providing a better understanding of the life cycles of CDD materials.

Other research highlighted in the report include best management practices to prevent and control hydrogen sulfide (H2S) and reduce sulfur compound emissions. This research can help support landfill owners and managers as they make choices that can ultimately cause or prevent their landfills from jeopardizing human health or creating nuisances like strong odors.

Hydrogen sulfide is a poisonous, flammable gas and, even at low concentrations, has a powerful, rotten-egg smell. It can be produced by either material solid waste or CDD waste, and once formed it is difficult to eradicate. Since H2S is slightly heavier than air, it tends to pool near ground-level where people are susceptible to breathing it in. At high levels, it can cause olfactory paralysis and go undetected, potentially causing respiratory distress or even death. Because of this, landfill managers must take preventative measures and cannot solely rely on odor complaints as a primary indicator.

CDD landfills are particularly vulnerable to H2S issues as they often receive waste material that includes gypsum drywall, which is high in sulfur. Other factors contributing to H2S formation include organic materials like wood, sulfurous industrial sludges, moisture, and anaerobic conditions.

EPA scientists researched and compiled best management practices for CDD disposal sites to reduce H2S emissions, including liquids management, minimizing the area of the landfill that is actively accepting waste, using daily cover, and diverting drywall from landfill.

The research resulted in the creation of EPA’s H2S Calculator App. The app user enters a few basic inputs for conditions at a given site and receives a worst-case-scenario estimate of H2S formation. Next, the user is directed to a simple guided checklist of management options. While the app was designed with landfill owners and managers in mind, it has potential as a tool for first responders in the wake of hurricanes or other disasters, as debris is rapidly removed, sorted, and, if possible, stored for reuse.

The research findings highlighted in EPA’s report will help push forward the practice of CDD sustainable materials management, a field ripe with opportunities to increase community sustainability and vibrancy. Data gaps and opportunities for further research were emphasized throughout the report, including the need for a large-scale market analysis of CDD diverted from landfills. As the state of available knowledge and data progresses, sustainable materials management can become more widely, safely, and efficiently practiced, benefiting the health of ecosystems and communities.

References

1. Tolaymat, T. Sustainable Materials Management Options for Construction and Demolition Debris; EPA/601/R-18/001; U.S. Environmental Protection Agency, Washington, DC, 2018.

2. Sustainable Materials Management. U.S. Environmental Protection Agency, 2018.

3. Jain, P.; Powell, J.; Tolaymat, T. Methodology to Estimate the Quantity, Composition, and Management of Construction and Demolition Debris in the United States; EPA/600/R-15/111; U.S. Environmental Protection Agency, Washington, DC, 2015.

4. Tolaymat, T.; Carson, D. Best Management Practices to Prevent and Control Hydrogen Sulfide and Reduce Sulfur Compound Emissions at Landfills that Dispose of Gypsum Drywall; EPA/600/R-14/039; U.S. Environmental Protection Agency, Washington, DC, 2015.