Case Study: How MetaFLO’s Solidification Reagents Improve Tunneling Waste Management

Tunneling under a dense urban environment comes with many challenges, one of the foremost being, tunnel muck waste management. The Eglinton Crosstown West Extension project, a 9.2-km extension of the light rail transit system in Toronto, Ontario which began in 2021, was no exception.

To address this large volume, tunnel muck management challenge, they utilized MetaFLO’s MF006 reagent, which has been engineered to meet the solidification requirements of water-based semi-solids like tunnel muck. MetaFLO worked with Di-Corp, a Canadian manufacturer and distributor of specialty chemicals, underground tooling and accessories, to supply the solidification reagent.  

How It Works

MetaFLO’s reagent turns tunnel-boring muck into a stackable, earth-like, solid material. Once the wet muck is solidified and tested to meet clean fill criteria, it can be transported in standard dump trucks and disposed of at local clean fill sites as rehabilitative clean fill. Any soil tested that does not meet the clean fill criterion, can be isolated and directed to the appropriate disposal site.

Historically, a range of dry amendments have been used to meet solids criteria or wet muck is transported to a transfer station where amendments are added. The addition of dry amendments bulks the muck significantly and can change soil properties, limiting re-use opportunities, increasing the volume of trucking required and increasing costs in the entire value chain in muck management.

Less Risk, More Efficiency

Compared to historical tunnel muck waste management methods, using MetaFLO requires a dosage of approximately 0.3% wt/wt resulting in 54% fewer trucks to transport solidified material. This improves trucking efficiency, takes less time, lowers emissions, reduces cost and improves community relations.

“Low-technology, bulking solutions such as sawdust, portland cement or lime to dry out the tunnel muck have been in place for decades and are largely redundant as a default solution,” said Andrew McNabb, President and COO of MetaFLO Technologies. “New and improved processes, such as applying MetaFLO’s reagent while utilizing purpose-built feed equipment can have a positive impact on overall site operations. Increasing the speed of solidification treatment, eliminating bulk amendments, improved utilization of labor and equipment contribute to improving project efficiency and environmental outcomes.”

Reduced Cost and Environmental Impact

MetaFLO reduces the environmental impact of massive projects like the Eglinton Crosstown West Extension in significant ways. 

“Liquid material disposal poses unique challenges, including the risk of groundwater contamination. Inappropriate disposal can potentially leach and contaminate water tables, affecting everything from wildlife to food security. Compliance with environmental regulations is an important consideration in all project planning, and MetaFLO reagents meet or exceed compliance criteria,” said McNabb.

MetaFLO’s environmentally inert reagents do not impact soil acidity, alkalinity, or natural microbial activity, unlike traditional solidification amendments like lime, cement, or sawdust.

Treating slurry on site also requires fewer trucks to move treated material to its final destination, representing a 63% reduction in greenhouse gas emissions, according to Argonne National Laboratory, and a 33% cost savings on average.

Learn more at www.metaflotech.com or send an email to info@metaflotech.com