Recovering Four Marketable Materials with the Ellicott® Series 370
The Problem: Limited Reach and Wasted Resources
The City of Springfield, Illinois, owner and operator of City Water Light & Power (CWLP), faced a challenge in managing three byproduct streams from its coal-burning facility: fly ash, bottom ash, and lime.
- Inefficient Recovery: Previously, the city used backhoes along the pond edges, but their limited reach left up to 90% of the material underwater and inaccessible.
- Logistical Hurdles: The waste products were flushed to settling ponds where they settled over large areas, making manual recovery almost impossible.
- Economic Potential: Markets existed for these materials—bottom ash for shingles, fly ash for highway construction, and lime for neutralizing agricultural soil—but the city needed a way to extract 100% of the deposit.
The Solution: The Ellicott® Series 370 Dragon®
After investigating various excavation technologies, CWLP opted to lease an Ellicott® Series 370 Dragon® cutterhead dredge. The city chose to operate the dredge with its own personnel, who were trained on-site by Ellicott® field engineers.
- The Equipment: The 12-inch Series 370 was selected for its versatility and ability to handle viscous materials. Despite working in cold winter months, the dredge experienced virtually no downtime.
- High-Density Pumping: The dredge moved lime slurry through 2,000 feet of pipeline at 50% solids by weight, maintaining a flow of 4,100 GPM.
- Maximized Reach: The 370 allowed the city to mine material underwater up to 2,000 feet away from the staging area—a distance impossible to reach with conventional land-based equipment.
- Strategic Staging: By discharging the slurry into a centralized area, the city allowed the material to settle and dry, where backhoes could then easily load the 100% recovered material for sale.
Outcome: $285,000 in Immediate Savings
The dredging program was a major breakthrough for the City of Springfield, delivering results that exceeded all expectations.
- 50% Cost Reduction: The city spent just $1.80 per cubic yard using the Ellicott® dredge, compared to the lowest outside contractor quote of $3.85.
- Significant Financial Savings: During a short initial dredging period, the city saved over $285,000 compared to conventional excavation techniques.
- Cleaner Effluent: By cleaning out the spillway structure, the dredge improved the settling of solids, resulting in a cleaner effluent stream from the ponds.
- Proven Performance: Project manager Mark Shea described the Series 370 as “the most cost-effective piece of equipment ever brought onto this property,” proving that a single machine could efficiently recover three different industrial byproducts.