Phil Dennis and Stefanie Bothwell to Present on Black Goo at the Canadian Waste to Resource Conference

Phil Dennis and Stefanie Bothwell (Ontario) will present “Waterloo Landfill Biofouling (Black Goo) Characterization and Treatability Study” at Canadian Waste to Resource Conference at the Blue Mountain Resort in Collingwood, Ontario, at 2:00 p.m. EDT on Monday, April 24, 2023.

Phil and Stefanie’s co-presenter is Brittney Crawford from the Region of Waterloo.

Phil is a Principal Molecular Biologist with more than 20 years of experience focused environmental microbiology, molecular genetic testing, enhanced bioremediation, and technology commercialization. He currently directs the molecular testing services and next-generation sequencing and is the innovation lead for SiREM’s research and development program. He has also played a leading role in developing relationships with many universities and serves on the Board for University of Waterloo Center for Microbial Research.

Stefanie is a Senior Staff Engineer in the wastewater process engineering group of Geosyntec Consultants. She designs and operates pilot treatment systems for industrial wastewater and groundwater; performs industrial wastewater site investigations; implements complex data collection programs at industrial wastewater facilities; handles wastewater characterization, treatment options, and permitting; and evaluates contaminant fate and transport as a part of sustainability reviews for industrial chemical facilities.

The Canadian Waste to Resource Conference will bring together the best minds and leaders in the waste, recycling, and resource-recovery sector from across Canada and Europe and will provide international perspectives and thought leadership on the multifaceted issues facing the industry.

Biofouling, also known in the landfill-operations industry as black goo, was discovered at the Waterloo Landfill in 2012, in the leachate collection system. It reappeared in 2017, disrupting the operation of the landfill gas collection system. After the 2017 event, the black goo has been discovered in the perimeter leachate collection system and all of the leachate pump stations. Due to the prospective operational concerns, the Region engaged Geosyntec Consultants and SiREM Labs in 2017 to initiate background studies to assess and characterize the material. SiREM performed benchtop treatability tests to determine the efficacy of various remediation amendments and to characterize the biofouling material using Next Generation Sequencing (NGS). With the goal of full-scale site deployment of a treatability system, the investigation continued in January 2022 from the benchtop study to the construction of a pilot-test system. The in situ pilot system is currently in operation, investigating the conditions that led to the growth of the biofouling material and examining a range of chemical amendments that could be dosed to reduce growth or remove the biofouling material from the leachate system. The pilot data collected includes organics, nutrients, methane, and other analytes collected in the influent leachate, bioreactor mixed liquor, biofilm material, and effluent; and NGS and adenosine triphosphate (ATP) data of biofilm samples to investigate the resemblance of biofouling material in the bioreactors compared to the material collected in the landfill and biological activity. Concurrently, the Region along with Geosyntec and SiREM Labs have been working with Dr. Laura Hug and her research team at the University of Waterloo to help analyze, characterize, and develop a data repository of the biofouling samples collected at the Waterloo Landfill.

In response to the January 2022 Waste 360 article, “Mission Black Goo: Figuring Out What It Is and How to Tackle It,” the Region initiated discussions with Dr. Craig Benson from the University of Wisconsin-Madison. The Region then spearheaded a working group composed of Geosyntec Consultants, SiREM Labs, Dr. Laura Hug, and team from the University of Waterloo. This group is working collaboratively to share and analyze biofouling samples from landfill sites across North America to determine if there are any analogous factors leading to biofilm growth.

It is evident that the emergence of black goo is a complex and relevant issue for landfill operators. The Region anticipates that the ongoing studies and collaborative research efforts will yield effective treatability strategies and will provide a comprehensive databank for sample comparisons.

More Information

About the event:
For consultation regarding treatability studies, contact Phil Dennis at or Stefanie Bothwell at
Learn more about Phil: Phil Dennis | LinkedIn
Learn more about Stefanie: Stefanie Bothwell | LinkedIn