Case Study: HDD Slurry Solidification for Safe Handling and Disposal

In this case study, we present the application of MetaFLO’s solidification technology in a Horizontal Directional Drilling (HDD) project in São Paulo, Brazil. Using MF003, it was possible to solidify slurry with free water in up to 30 minutes, enabling safe handling and disposal of the waste.

The Challenge of Waste Management in HDD Projects

As is common in HDD operations, the process generates large volumes of slurry resulting from the mixture of excavated soil, drilling fluid, and water. When this waste still contains free water, it must be fully solidified for proper disposal due to the risk of leaching during transportation on public roads, which can lead to environmental and regulatory concerns.

Before implementing MF003, the company responsible for the project used an alternative method to convert the drilling waste into a solid material. However, the process was not sufficiently efficient.

To enable disposal, it was necessary to incorporate 100% to 200% of dry soil into the material, followed by a drying period of up to one week. This procedure made the process slow, increased the final waste volume, and significantly raised logistical costs.

Seeking a more efficient solution to ensure project progress, the Environmental Department responsible for the operation opted to apply MF003, an environmentally safe product that enables rapid slurry solidification, eliminates leaching risks, and allows for proper waste disposal.

How Was the HDD Slurry Solidified?

Before application, the dosage of the MF003 solidification reagent was calculated and adjusted according to the moisture content of the slurry generated during the operation, reaching up to 0.75% for a volume of 6.5 m³ of material.

Once the appropriate dosage was defined, MF003 was applied directly to the slurry generated from the HDD operation.

To incorporate the reagent into the material, the excavator available on-site was used to mix the product with the slurry until full homogenization was achieved.

Within 30 minutes, the free water present in the material was absorbed, transforming the waste into a solid, stackable material. This eliminated the risk of leaching and enabled safe handling, transportation, and environmentally compliant disposal.

Final Waste Volume

One of the main efficiency gains from solidifying HDD slurry with MF003 is the elimination of the need to add large volumes of dry soil, using dosages as low as 0.75%.

These low product dosages result in a significantly reduced final waste volume compared to traditional methods.

In practice, this means:

• fewer trucks required for transportation
• less space needed for storage or disposal
• reduced operation time
• lower overall logistics costs