The good news comes from Holdex Environnement in Le François, known under the brand name «L’idée Verte»…And this company, which produces organic soil amendments and was founded in 2007 by Mike Bernus, is certainly not short on ideas—it has found a way to compost fresh sargassum!
An initiative by 100% Sustainable Development, 100% Local Supply Chain, and 100% Martiniquaise. Holdex specializes in the production of compost made primarily from local green and organic waste: sugarcane bagasse, laying hen manure, eggshells, and other natural materials derived from poultry byproducts and sugarcane—and, more recently, sargassum seaweed!
Martinique 2030: How long have you been working -you on this topic?
Mike Bernus: Over the past five years, we have conducted numerous preliminary studies as part of an expansion project aimed at adding value to Sargassum seaweed. We were able to address the various challenges that arose. Based on the analyses we conducted, we determined which process to implement to recover value from this seaweed despite the challenges it presents, such as sand and sodium.Our company was selected as a winner in a call for expressions of interest launched by ADEME in 2015. We were the only ones to offer a viable, proven solution, since we drew inspiration from the green algae in Brittany, which are far more harmful than Sargassum. We were able to develop a highly specialized process with our engineering firm in mainland France to make the most of it.
M 2030: Does this algae bind heavy metals—arsenic, and perhaps even chlordecone? Can it be considered a decontaminant? Could it be used to decontaminate soil? And in your case, how can we ensure the final product is uncontaminated?
MB: The entire Atlantic coast is currently affected by the problem of seaweed. As part of our recycling project, we were asked to collect the seaweed that washes ashore at Le François, Le Vauclin, all the way to Sainte-Anne and Le Diamant. We therefore focused our analyses—which were conducted by certified laboratories—on the issues of arsenic and heavy metals, as well as chlordecone. It turned out that the test results for this geographic area showed no presence of chlordecone. No one has really focused much on the issue of chlordecone or whether this algae can accumulate it, but that will come. We had to submit all our test results to the relevant authorities because we’re subject to very strict regulations in order to be allowed to operate.
As for heavy metals, there is no question of using pure algae in our processes. We have conducted various experiments to establish these processes, followed by analyses comparing the results to the standards to which we are subject: NFU 44051 and NFU 44551. These standards specifically address the maximum permissible levels for heavy metals. Our results show that we are well below the established thresholds in this area. This is a major plus for us, since our policy and core business revolve around natural 100%; we produce for organic farming and use no chemical additives. We develop our products using only mechanical processes and by blending specific raw materials that we have identified in advance based on our needs and the results we wish to achieve. These materials play a specific role in the formulas we have developed for agriculture and consumers. We then compared our products with competing commercial products and found that our algae-based products contain significantly lower levels of heavy metals than those of our competitors.
It’s important to understand that we don’t use pure seaweed. We face too many regulatory constraints to be able to do just anything, and besides, the quality of our products and the reputation of our registered brand are at stake. Our products are also intended for export. The challenge for our team is to create the best possible product—one that’s as natural as possible—while complying with all regulations.
M 2030: You’ve solved the problems of salinity, sand, and heavy metals—what about the arsenic problem?
MB: There, too, we found levels below the standards, and we were asked to repeat the tests to verify this. The tests were conducted by an accredited laboratory and submitted to the relevant authorities, and everyone was surprised to see that the levels were well below the accepted standards. For us, Sargassum seaweed is, above all, an important source of trace elements and microorganisms in our products. Without giving everything away, it will accelerate the microbial activity in our products and serve as fuel for the microorganisms that interact between the soil and the plant.
M 2030: What about H2S?
MB: It is present when seaweed decomposes, but we accept it when it has been on the shore for one to three days—it’s still fresh. And as soon as we receive it, we process it; we don’t store it—we repurpose it right away.
M 2030: What is the process?
MB: I can't say—it's a secret; there's a patent. We spent five years developing this. All I can tell you is that the seaweed is mixed immediately to prevent fermentation. The materials we use absorb the H2S.
M2030: How much volume will you be able to process?
MB: With the planned expansion to process sargassum, we’re moving to a new operating model, since we currently process 25,000 metric tons of raw materials, and with the addition of sargassum, we’ll increase that to 60,000 metric tons—so our operating model is changing. We’ve taken the necessary steps to ensure optimal recycling, and we’ve positioned ourselves to 30,000 metric tons of seaweed per year. It will already be a good thing to be able to remove a large portion of what’s along the coastline and provide relief to the people of Martinique. We’ve started collecting it. Last week, we received 900 square meters from Anse Michel.
M2030: Regarding trash collection, is it organized efficiently?
MB: The issue of cleanup is complicated because Martinique’s terrain makes recovery difficult, and we also have to try to preserve the environments where they’re located—we don’t want to damage them with excavators…It’s true that, given the extent of the damage, the response isn’t fast enough, but this is a recent phenomenon we’re not used to, so things are falling into place little by little. It’s also an intermittent phenomenon—sometimes there are debris piles, sometimes not. It turns out we’ll be seeing more and more of them, but no one has a clear picture of what to expect. We can always do better, but I think we’re making progress.
M 2030: Is Sargassum a resource?
MB: For us, this represents considerable potential, but we need to determine what kind of potential we’re seeking through the use of these algae. The strength of our business is that it isn’t based on the processing of sargassum. If we don’t have seaweed, we operate just fine, and if we do have it, we know what to do with it. We’re not going to invest in a dedicated seaweed processing facility—which would be prohibitively expensive—to replace plastic, because the day there’s no seaweed, we’re stuck. We mustn’t forget that we’re an island. We have to work within our means. We’ve integrated it into our business, which is why it took some time. We took an interest in this seaweed as soon as the first shipments arrived. It's still a valuable resource—it all depends on how you use it.
M 2030: When will the first sargassum-based composts be available?
MB: In a year and a half! We have a year of work ahead of us because the process for recycling seaweed is quite complex. The products we’ll be producing include organic soil amendments—which are fertilizers free of chemical additives—as well as other growing media, such as all-purpose potting soil and organic mulch… The goal is to replace imported products. We're proud of what we do because it's all made right here in Martinique; our products are of much higher quality than what you find on the market. We’re right in the thick of sustainable development. Currently, all the imported potting soils we’re aware of are made from peat—a resource that’s dwindling and isn’t locally sourced. We’ve been able to replace this material with locally sourced materials such as green waste and sugarcane bagasse—these are clean products. We operate a short supply chain, distributing our products locally to businesses and individuals. The only thing we import are our bags.
Interview by Nathalie Laulé
