In 1978 DEME began to further diversify its activities, establishing Bitumar, a specialist in erosion control and hydraulic engineering solutions. The new company initially focused on stone asphalt, sand asphalt and bitumen membranes, materials widely used in hydraulic engineering.

Stone asphalt helped protect riverbanks and coastal structures against erosion, while sand asphalt was applied in temporary shoreline structures and coastal breakwaters. Bitumen membranes, meanwhile, enabled the construction of water basins and other hydraulic infrastructure.

Then the introduction of HDPE liners opened up even more new possibilities. Though HDPE was originally developed to contain water, it could also be used to isolate contaminated sites, protect the environment from industrial activities and prevent the spread of pollution. This marked a significant shift, expanding the company's focus from hydraulic engineering to environmental protection.

The years that followed saw the creation of complementary businesses such as Silt, specialized in the treatment of dredged sediments, and Soils, which focused on the remediation of contaminated land. Together, these activities laid the foundations for what would later become DEME's Environmental segment and our ongoing focus on remediation, sediment treatment and brownfield redevelopment. Building on this growing expertise, these activities gradually evolved into a dedicated environmental business within the group.