Abstract
The Bureau of Mines conducted a feasibility study and designed an operational system for consolidating waste coal sludge in a 110-acre pond by applying direct current between buried and floating electrodes. Consolidation would reduce the sludge to half its present volume, thereby extending the working life of the pond as well as creating a safe, stable impoundment. The project was conducted by the Bureau under an agreement with the Washington Irrigation and Development Company (Widco), located near Centralia, Washington. Part 1 of this report, published as report of investigations 8666 in 1982, covers the results of laboratory tests at the Bureau's Spokane Research Center and of a small-scale field test at Widco's coal preparation plant. Test results show the process is efficient and cost-effective when power is applied at low current density. Part 2 (this paper) describes a detailed design for an electrokinetic system to dewater Widco's 110-acre pond with a 27.4-Acre electrode array. Densification of the inactive sludge pond will require 3.6 Yr of treatment for a total cost of $1,450,000. The study and design are site specific, but design procedures and analyses are sufficiently detailed to serve as a guide for applying the process to any sludge pond.
