Industrial ecology and revegetation of a mining site from tailings: the case of Chapais Énergie
Courtesy of Marc Hébert, M.Sc., Agr

The Chapais Énergie plant, owned by Nexolia, produces and sells electricity to Hydro-Québec. This renewable energy is produced by the combustion of residual biomass from the wood industry. However, the costs of burying the ashes are high. Work was therefore undertaken to recycle these residues in order to revegetate an orphan tailings site located near the homes of Chapais. The deep incorporation of ash at high doses increased the porosity of the substrate, promoting natural drainage of the site without liquid discharge. This then made other revegetation work possible. This daring technique allowed for the rapid creation of an abundant and permanent vegetation cover preventing wind erosion and contamination of the air by arsenic. There was colonization by herbivorous fauna, especially voles, as well as various species of birds and pollinating insects, then by predators including foxes and several species of raptors. This project has additional advantages, including the creation of a park and biological and chemical carbon sequestration and is a great example of industrial ecology.

NEBRAMail Note: Long-time NEBRA member Marc Hébert was a residuals regulator in Quebec for over 27 years. He is now a consultant and trainer and had been publishing a monthly newsletter, MRF Actualities (http://marchebert.ca/publications/), for many years – what he calls his “Science Journalism Project”. Marc emailed NEBRA on November 1st to announce he is embarking on the next stage of his life which includes slowing down (just a little).

UNH Researching Fate of PFAS Through Wastewater Treatment Processes

Dr. Pauler Mouser, Assistant Professor in the Civil & Environmental Engineering Department at the University of New Hampshire reported on her team’s research into the “Fate of Long Chain and Short Chain PFAS Compounds in Wastewater Treatment Facilities” at the first session of the 2020 Northeast Residuals & Biosolids Conference held on October 1st. The research involved extensive sampling for 24 PFAS at numerous Water Resource Recovery Facilities (WRRFs) in New Hampshire at various process stages. In summary, the researchers found fractionation of PFAS through the wastewater treatment process – that is, PFAS separating into the water-loving compounds (mostly shorter chains that end up in the effluent) and water-repelling compounds (mostly longer-chain and precursors compounds that end up in the wastewater solids). They also found further fractionation depending upon the solids stabilization process. For example, although the total concentrations of PFAS remained the same following anaerobic digestion and composting, for some reason the composting process resulted in more short-chain PFAS compounds with the digested solids containing more precursors. Dr. Mouser noted that PFOS concentrations in most of the biosolids products sampled were above the Maine screening standard.

Dr. Mouser spoke of future research needs – especially the environmental fate of long- versus short-chain PFAS which will be needed to inform regulation of land-applied biosolids. In response to a question, Dr. Mouser said she would love to fund some graduate students to focus on the difference in PFAS concentrations resulting from different biosolids stabilization approaches.

PFAS Cost Impacts Study Led by NEBRA Getting Noticed

The recently released report “Cost Analysis of the Impacts on Municipal Utilities and Biosolids Management to Address PFAS Contamination” prepared by CDM Smith for the Water Environment Federation (WEF) and the National Association of Clean Water Agencies (NACWA) has been getting a lot of mention in clean water circles. WEF and NACWA have assisted NEBRA in getting the word out. WEF has published a blog by CDM Smith Project Manager – and Chair of the Residuals Committee for the New England Water Environment Association – Eric Spargimino. WEF has also included a related Viewpoint article by NEBRA Executive Director Janine Burke-Wells in its December edition of Water, Environment & Technology magazine. Eric and Janine participated together with Chris Wilson, Chief of Processing, Engineering and Research at Hampton Roads Sanitation District in a Words On Water Podcast #170. The WEF/NACWA/NEBRA report was also cited in Water Finance & Management [https://waterfm.com/new-report-underscores-cost-impact-of-pfas-on-potws-biosolids-facilities/] and Global Water Intelligence magazines [https://www.globalwaterintel.com/]. The next step is to get the report and this important information into the hands of federal and state legislators and regulators.

National Biosolids Data Project Update

The National Biosolids Data Project (NBDP) being led by NEBRA is progressing nicely. The NBDP is being implemented by a great team including personnel from the Northwest Biosolids Association, the Mid-Atlantic Biosolids Association, the California Association of Sanitation Agencies, and BioCycle. Thanks to the financial support of numerous partners, NEBRA has received full funding to complete this long-overdue project – collecting and compiling data on the regulation, quality, end use and disposal of biosolids in the United States. NEBRA even received a little extra in pledges which will allow the project team to put extra effort into compiling energy and economic data. Thanks to NACWA and WEF for leadership contributions and to the wide variety of organizations from around the country that have pitched in to ensure this important data resource is completed. A final report is expected at the end of March 2021.