The Drama Beneath Your Feet

Written By Rachel Rae

Civil engineer Ernie Hines walked us through the slow-moving disaster happening inside concrete infrastructure everywhere. The fix has been around for decades. The problem is nobody talks about it until something collapses.

Infrasound Podcast | reVerb Communications

In January 2024, a pickup truck drove over a stretch of road in Iowa and fell through. Beneath it, an 86-inch trunk sewer line feeding a wastewater treatment plant had corroded to the point where it couldn't support the weight of an F-150.

The pipe was bare concrete. No protective liner. Bacteria had been converting hydrogen sulphide gas into sulfuric acid on its interior walls for years, softening the concrete until it crumbled. The truck just happened to be the thing that made it visible.

That story came up midway through our conversation with Ernie Hines, a civil engineer and technical product manager for concrete protective liners and geosynthetics at AGRU America. Hines flew to Calgary to speak at a CPL Academy session. We caught him for an episode of Infrasound. What followed was a surprisingly gripping tour of everything that's going wrong beneath the surface of every city you've ever lived in.

Concrete Has Two Kinds

There's a saying Hines shared that stays with you: there are two kinds of concrete. Concrete that has cracked and concrete that hasn't cracked yet.

Concrete is a calcium-based material. That makes it a base. Acids eat it. Moisture penetrates it. Reinforcing steel inside it corrodes and causes spalling, where chunks of surface break away. And in wastewater environments, a process called microbial induced corrosion (MIC) turns the structure's own chemistry against it.

Here's how MIC works. Decomposing waste generates hydrogen sulfide gas. That gas rises above the water line inside a pipe or structure and condenses on the concrete surface. Bacteria colonize that surface, building a slime layer. Over time, the bacteria convert the hydrogen sulfide into sulfuric acid. The acid softens the concrete. Turns it to chalk. The structure begins crumbling from the inside.

In high-risk environments, this can render a concrete structure useless in as few as five to ten years. Engineers know where it's most likely to happen: drop manholes, pumping stations, digesters at wastewater treatment plants. Anywhere hydrogen sulfide concentrations are high. The at-risk structures are identifiable. The question is whether anyone acts before a truck falls through.

A 30th Birthday in a Pumping Station

The solution Hines brought with him, literally, to our recording session is a concrete protective liner. A sheet of high-density polyethylene, typically two to five millimetres thick, anchored directly into the concrete with embedded studs. The plastic does what concrete can't: resist chemicals, block moisture, withstand abrasion.

CPL technology has been around for about 75 years. AGRU has been manufacturing it for roughly 40. It's been used in Canada for 30.

That 30-year mark came up in a story Hines told about a pumping station in Florida. The municipality had been cycling through spray-applied and roller-applied coatings for years. In 1995, they installed a concrete protective liner. In 2025, an AGRU engineer went down, pressure-washed it, inspected it. The city representative's assessment: every other structure in the system had problems. The ones with CPL never did.

The engineer made a birthday card on the back of a piece of liner. Brought a chocolate cake. Left it outside the pumping station. Nobody ate the cake.

The Geosynthetics Research Institute estimates that a buried geomembrane made from the same resin as CPL has a half-life of over 440 years at certain temperatures. In a wastewater environment, Hines puts the practical service life at 50 to 100 years.

The Problem Nobody Campaigns On

Glenn asked Hines to recall the last time hydrogen sulphide was a municipal election topic. The room went quiet.

This is the fundamental challenge with subsurface infrastructure. It's invisible until it fails. Voters don't demand action on things they can't see. Elected officials balance budgets against lifespan, and the math often favours the short term. Hines put it bluntly: "Sometimes we get the impression they're like, 'Well, it only has to last 10 years because I retire.'"

The American Society of Civil Engineers gives US wastewater infrastructure a D+ rating. In Calgary, the 2024 water feeder main break that triggered weeks of restrictions wasn't an isolated event. The city experiences up to 170 smaller failures per year. The work is largely reactive.

The cost difference is staggering. Repairing a few feet of failed pipe costs a minimum of ten times the per-unit price of new construction. Mobilization, excavation, disruption. Every emergency repair is an argument for having done the job right the first time. And "right the first time" is the entire value proposition of concrete protective liners: spend marginally more upfront, get decades of service life, avoid the emergency dig.

The Plastic Stigma

Hines works for a company that manufactures thermoplastic products. He knows what people think when they hear the word plastic. They think of the Great Pacific Garbage Patch. Microplastics. Single-use water bottles.

What they don't think about is the polyethylene membrane between a hazardous waste landfill and the groundwater. Or the liner inside a subway tunnel beneath Los Angeles, installed to prevent methane from accumulating and causing an explosion. (That concern stems from a 1985 incident at a Ross Dress for Less store in LA, where naturally occurring methane caused a flash that injured over 20 people and shut down an entire retail district.)

The LA Metro is currently expanding its subway system ahead of the 2028 Olympics. AGRU is lining those tunnels with hydrocarbon-resistant HDPE membranes.

Modern landfills, too, are lined engineered systems. Hines bristles at the word "dump." Today's facilities use multiple layers of geosynthetics, textured geomembranes with interface friction to prevent slope failure, and drainage systems that capture leachate before it reaches groundwater. The industry learned hard lessons from the Kettleman Hills hazardous waste facility failure in the late 1990s, when layers of geocynthetics slipped against each other and part of the landfill simply moved. That event reshaped how the entire sector designs containment.

Almost everything AGRU does connects back to water. Protecting groundwater from contamination. Transmitting potable water through fused polyethylene pipe with zero acceptable leakage (the same standard applied to natural gas lines). Lining canals in the western US to prevent irrigation water from being lost to infiltration and evaporation. The average American water system loses 14% of its treated water between the plant and the customer. Most of that loss is pipe joints that have separated or were never properly sealed.

Why It Matters to People Who Never Think About Pipes

Hines said something near the end of the episode that deserves to sit with anyone who works in public infrastructure communication. Civil engineers, he argued, have saved more lives than the entire medical profession. Sanitary systems. Water treatment. Safe bridges and tunnels. The infrastructure that keeps disease, contamination and structural failure out of daily life.

Hollywood hasn't figured that out yet. There's no civil engineering drama on Netflix. Engineers, Hines said, "are not the most interesting people. At least unless they're talking to one another."

We'd push back on that. The story of a bacteria colony slowly converting a concrete structure into chalk while a city goes about its day above is genuinely dramatic. The story of an anchor stud design being refined millimetre by millimetre to resist hydrostatic back pressure is the kind of iterative problem-solving that keeps cities standing. The story of a pumping station getting a birthday cake after 30 years of uninterrupted service is, in its own way, moving.

The infrastructure beneath our feet doesn't ask to be noticed. It asks to keep working. The people who make that possible deserve a longer conversation than they usually get. This episode was ours.

Referenced in this episode:

Infrasound is produced by reVerb Communications. We tell the stories behind the infrastructure that shapes how communities live, move and grow.

Rachel Rae
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