Consider Sustainable Remediation - Just Leave Well Enough Alone!?!

When historical soil and groundwater pollution is discovered, remediation is usually required by the authorities.? Remediation science and technology implementation is indicated in almost all situations.? It’s fun and rewarding to implement remediation, and to watch it progress be sure, followed by an end meeting mandated clean-up standards.?

Remediation is usually a relatively (1) long-term, (2) expensive, and (3) carbon emission intensive endeavor.?

·?????? My shortest remediation project took 3 years, and my two longest started in the 1980s and are still ongoing almost 50 years later (…without me since I retired).?

·?????? My annual remediation spending on each of a 2-3 dozen projects simultaneously was anywhere from about $100k US per year to over $2MM per year per site.?

·?????? I haven’t ever calculated the carbon intensity and how much the net environmental improvement was, but it’s something I thought about in the last few years. I say net environmental improvement, because it took resources to remediate – might there be a net negative environmental impact from remediation? ?Hmmm….

In my opinion, executing a remedial action is not always necessarily nor applicable everywhere in every contamination situation.? The earth, like our bodies, has an amazing ability to recover from chemicals - there are amazing stories of human survival and recovery from years of substance abuse.? This is not the case always, and there are stories of exposure to chemicals that causes acute and chronic issues that can lead to death.? I won’t use absolutes as that’s disingenuous.? But on the same token, again, remediation should not ALWAYS be indicated, as the earth can heal itself in some situations.?

For example, I had a long-closed herbicide production plant with a groundwater plume that had left the property boundary.? We had an operating onsite and offsite groundwater recovery system.? The recovery system had been in operation for almost 40 years when I inherited it.? I asked myself and my experts “when will it end?”? We did something unorthodox and counterintuitive.? We had some indication in the historical groundwater data that when the recovery system was shut down, aquifer contaminant concentrations declined at a greater rate than when we were actively recovering contaminated ground water.? We convinced the authorities (not easy) with our data to allow us to do a 2-year trial shutdown of the offsite recovery system.? Concentrations dropped precipitously over that 2-year trial!? We never restarted the offsite system and it’s been almost 10 years now.?

The phenomenon above had to do with the native bacteria that break down the contaminants being able to thrive in flooded and reducing conditions, rather than the oxidizing conditions that existed under pumping conditions.? Sure, the bulk of the contamination needed to be initially removed, but beyond a point in time, it was counterproductive.? We were wasting energy, materials, time, and money interfering with a natural process that could take care of itself FASTER than we could.? Work WITH the earth, not against it.

Let's also add another concept that simplicity may be better.? One of my projects involved investigating the footprint of 36 separate leaded tank bottom burial pits.? In the “olden days” when leaded gasoline was used in the US, large above-ground gasoline storage tanks at refineries would have to have the lead sludge removed periodically.? The side of the tanks would be cut open for large equipment entry (the welded-closed openings could still be seen decades later).? The sludge would then be shoved out of the tank and into a hole in the ground adjacent to the tank within its earthen secondary containment.? The state in the 1990s required us to FIND each pit, determine nature and extent of each, and start remediation if necessary.?

My predecessor had devised a classic environmental site investigation - soil borings would be done with a drill rig, guessing where the pits might be, soil samples taken depending on what was found, and lab analyses done for lead.? Cost estimates for the initial investigation were over $1MM in 1992 dollars.?

I was fresh out of school and not knowing what “everyone else” was expected to do at the time I suggested we use a back-hoe to dig trenches to look for the gray-black sludge, and then use a portable x-ray diffractometer on the back of a pickup tailgate to screen the adjacent soil samples for lead contaminant migration, and then select a few samples for lab analysis to confirm.? The State of Texas approved our plan.? The investigation was quick and decisive, no need for additional phases to fine-tune things!? It was better and cheaper by nearly $1MM.

So, with the concepts of self-healing potential of the earth and the elegance of simplicity, let us consider the concept of sustainability in the context of remediation.? It’s not a hard concept at all to understand.? It has to do with cost-benefit math (not talking about dollar-cost here).? I mentioned net environmental improvement, and it’s worth repeating – it takes resources to perform remediation and there might be a net negative environmental impact from remediation, if you’re not careful and thoughtful.? Many times, regulations and policy are used as an excuse to not allow this care and thoughtfulness – agencies won’t necessarily allow for it, you must actively pursue it, and even then, the “red-tape” is almost insurmountable.? There’s nothing in the regs that allows supposed inaction.

I’ll be back again to give real project examples where remediation sustainability should or still could be considered, if we want to truly be good stewards of earth resources foremost (sustainability), as well as company resources (financial performance) as a secondary benefit. These may apply in your project situation in some way.