A phosphate terminal, embedded within an active railyard, generates runoff that leads to a quarter-acre sized settling pond designed to settle out phosphate fertilizer and rainwater. Over time, the settled fertilizer build-up caused storm water inlet clogging, backups and high phosphate concentrations in the water.


The consistency of the fertilizer sludge was extremely wide ranging – from sandy and fluid, to mushy and pudding like, to thick and viscous as a concrete slurry exhibits. Despite the unique properties removal methods that had to considered, Hull’s was tasked with removing all of this from the pond without damaging the protective liner at the bottom. Additionally, since all storm water from the phosphate terminal is funneled through a variety of underground pipes to the settling pond, and diversion was not an option, Hull’s had to continually monitor and dewater the pond due to unpredictable Florida rain events.


Using a specialized, hydraulically driven 6-inch submersible pump, the fertilizer slurry and sludge portions of the pond were removed and discharged into frac-tanks staged onsite. Upon encountering any solidified portions of the pond, a heavy-duty excavator was utilized to dig, pile and eventually dry out those portions of the pond in an adjacent area. To maintain continual operations, tankers were used to vacuum the product from the frac-tanks and transport to a disposal facility. Due to the nature and consistency of the product, it was necessary to periodically implement the use of an industrial air mover for the cleaning and clearing of the vacuum tankers.


Over the course of six weeks and in light of various weather events, the coordination of activities using the sump, excavator, frac-tanks, vacuum tankers and industrial air-mover were key to keeping the project progressing and efficient. All phosphate fertilizer was removed to the hard bottom liner, all inlets were cleared and the pond was restored to full function. Ultimately, four million gallons of water were pumped, 400 tons of stackable solids were piled and relocated and nearly 1,000 tons of sludge was removed from the pond.


Six-inch, specialized, hydraulic submersible pump, four inch self-priming dewatering pumps, 49,000 lb excavator, vacuum tankers, roll-off boxes, roll-off trucks, industrial air mover and frac tanks.