After World War II, huge amounts of calcium phosphate and other phosphorus related chemical waste had been dumped into the lagoon in England. High levels of health and safety regulations were adhered to.
The bottom of the lagoon was first flattened. Due to the high level of phosphate in the water, the cutter suction dredger not only dredged soil, but also huge amounts of algae. To solve the problem of cludging, we equipped our dredger with a vegetation shredder. After 5 months of dredging and flattening operations, a huge geomembrane of more than 45,000 m2 was laid and completely covered the lagoon and its slopes.
Truckloads of capping material, mostly sand and recycled concrete, were tipped onto the site. The material was mixed with water and, by using a powerful gravel booster unit, the liquidised material was pumped on a spreading pontoon for its final destination as a capping layer to isolate the phosphorus contamination.