Grantee Research Project Results

Final Report: Sequestering Arsenic From Effluents in Construction and Demolition Wood Recycling (SAFE C&D Wood Recycling)

EPA Contract Number: 68HERC21C0025
Title: Sequestering Arsenic From Effluents in Construction and Demolition Wood Recycling (SAFE C&D Wood Recycling)
Investigators: Simonpietri, Joelle
Small Business: Simonpietri Enterprises LLC
EPA Contact: Richards, April
Phase: I
Project Period: March 1, 2021 through August 31, 2021
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2021) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR)

Description:

The research purpose of this project was to trial thermochemical techniques to be able to recycle organic construction and demolition debris waste (C&D) into a low-greenhouse gas transportation fuel, while safely sequestering common C&D contaminants from copper chromated arsenate (CCA) treated lumber.  This project prepared real-world C&D debris sampled from a commercial landfill in Hawaii and performed a series of gasification tests on a fluidized-bed bench-scale gasifier to generate ash, condensate, and gas from the C&D.  We then performed ultimate, elemental, infrared, toxic leachate, and chemical assay analysis on the effluents to baseline the profile of those effluents relative to each of the techniques.  Our research had a specific focus on the disposition of the toxic heavy metals arsenic and chromium.  We also performed technoeconomic analysis of a notional commercial scale plant through spreadsheet modeling to analyze the costs of our technical variations; as well as environmental analysis of the overall C&D recycling and gasification process to benchmark the environmental unknowns and permitting risks.

Summary/Accomplishments (Outputs/Outcomes):

The syngas produced from the C&D debris was an acceptable composition and generally compatible with commercial gas cleanup equipment and catalysts to be able to make renewable fuels from the C&D waste.  Both the fly ash and bottom ashes generated in the trial passed toxic characteristics leaching protocol (TCLP) tests by an independent certified laboratory for all criteria compounds of concern:  heavy metals, volatiles, semi-volatiles, herbicides, and pesticides.  

Conclusions:

Overall, the Phase I results showed that gasification of real-world construction and demolition debris is technically and commercially feasible.  The gasification trials proved our hypothesis that our innovations can successfully gasify real-world C&D debris containing the normal levels contamination that constrain other recycling methods; sequester arsenic and chromium in the ash; and that the leachate from the ash meets regulatory limits for toxicity.  In addition, the mineral composition of the ash generated from the gasified C&D waste was analyzed and compared to Portland Cement.  The results indicated it could be acceptable for further recycling by re-using the ash in concrete.

We met with several dozen entities, comprising customers, suppliers, end-users, investors, and regulators.  These included local Hawaii firms for partnering for our first commercial plant, and national and multinational firms for technical development and investment for commercial-scale system deployment in a pipeline of projects across the U.S.  This commercialization work led to written commitments for in-kind or cash support for further testing and commercial development from several firms.  We have several term sheets currently in negotiation with customers and investors.