Composting Seaweed: The “Green Gold” of the Gallet Family in Bel-Ombre

In Bel-Ombre, Yohan and Luc-André Gallet are transforming seaweed found on local beaches into what they term “green gold.” This sustainable initiative enriches the soil for growing vegetables, fruits, and flowers, and has garnered attention as part of their start-up, Sealife Organics.

On Monday, August 26, we visited Sealife Organics’ composting facility to learn more about their innovative process of converting marine waste into nutrient-rich compost and slow-release fertilizers.

During our visit, Yohan and Luc-André welcomed us and shared their knowledge and experiences in sustainable agriculture.

Founded in 2020, Sealife Organics specializes in the production of organic compost and fertilizers, including slow-release varieties and 100% seaweed-based biostimulants.

“We focus on creating compost and organic fertilizers that enhance soil health and support sustainable agriculture,” Yohan said.

The composting process is a careful blend of entirely organic materials, such as leaves, wood chips, seaweed, chicken manure, and eggshells, which create optimal growing conditions for a variety of plants.

Initially, the company manually produced about eight tons of compost per month, a figure that has now increased to 150 tons.

How Are Seaweed and Green Waste Transformed?

To create compost from marine algae, Yohan explained that his team collects Sargassum seaweed and Syringodium, a type of seagrass, washed up on the southern beaches.

“We do not remove anything from the water; we focus solely on the brown seaweed found on the shore.

We carefully collect it by hand, removing any sand, and then place it in bags for transport back to our facility,” he clarified.

As for green waste, Sealife Organics receives leaves, branches, bark, and coconuts from local gardens and tourist establishments.

“When trucks arrive with seaweed or green waste, we conduct thorough inspections to remove plastics and other prohibited materials.

Strict guidelines are in place, and if they are not followed, we return the waste to the sender,” Yohan emphasized.

Once collected, the seaweed and green waste are placed in designated processing areas.

In this space, which could be humorously dubbed “Green Mare-Chicose,” green waste such as leaves and branches is shredded.

The resulting mulch is then sifted, and the fine material is mixed with Sargassum and Syringodium.

This mixture is laid out in rows known as composting windrows over a prepared surface.

Afterward, supplementary materials, including eggshells, wood chips, and chicken manure, are added to enrich the mix with nutrients and accelerate decomposition.

To promote efficient composting, the mulch rows are regularly turned to aerate the material.

“This process raises the temperature of the compost, allowing it to decompose more rapidly,” Yohan explained.

Careful monitoring of moisture levels ensures the compost remains damp but not waterlogged.

For optimal temperatures to aid decomposition, the rows are covered with repurposed materials from a local company, Rent A Sign. “This helps protect the composting rows,” he noted.

Over time, microorganisms and bacteria break down the organic matter into rich compost.

“This process can take several months, depending on environmental conditions and compost management.

However, with our composting techniques, we can produce a finished product in about 12 weeks,” Yohan stated.

Once mature, the compost is sifted again to remove any large, undecomposed fragments before being packaged using semi-industrial equipment.

This mature compost is then used to enrich soils in gardens, farms, and orchards, providing essential nutrients to improve soil structure.

“Initially, when we started composting seaweed and green waste, all the work was done by hand. Since January 2024, we have transitioned to semi-industrial production thanks to support from our investors, including ENL Agri Ltd, Ingenia, Turbine, G.O.A.L.S, Seed Capital, and Jog Investment,” Yohan explained.

Sealife Organics currently offers a multi-purpose peat-free potting soil as well as slow-release fertilizers in various sizes, including 10-kilogram, 20-kilogram, 25-liter, and 50-liter packages.

“In the coming months, we will also introduce a 100% seaweed-based liquid biostimulant,” Yohan added.

What Are Slow-Release Fertilizers?

At Sealife Organics, slow-release fertilizers are designed to gradually supply nutrients to the soil, ensuring that plants receive continuous nourishment over an extended period.

These fertilizers contain essential nutrients such as nitrogen (N), phosphorus (P), and potassium (K), along with various micronutrients that are vital for plant growth.

This balanced nutrient delivery promotes uniform growth and enhances plant health.

“By optimizing nutrient use and reducing maintenance needs, slow-release fertilizers offer a sustainable and effective solution for agriculture and gardening in Mauritius,” Yohan said.

Can Invasive Seaweed Be Utilized?

Recently, large mats of invasive seaweed, specifically Ulva reticulata, have washed ashore at popular beaches such as Mont-Choisy, Palmar, and Flic-en-Flac.

As these algae decompose, they release hydrogen sulfide, a toxic gas that poses health risks, leading to their burial on several beaches.

But could Sealife Organics transform this invasive seaweed into compost and fertilizers?

“We are certainly interested in taking these surplus invasive seaweeds. We will explore what types of products we can create from them.

However, a public-private collaboration is needed for their collection and transportation to our composting facility in Bel-Ombre.

Currently, we are producing natural compost on a smaller scale. If these algae are routed to us, we will also need a permit to increase our production capacity,” Yohan concluded.

Source: Defi Media