Macawber Beekay offers High Concentration Slurry Disposal System (HCSD) for Fly ash and Bottom ash generated by coal fired power plants. The hydraulic transport of fly ash has traditionally been done in the form of dilute slurries, containing 10 to 30 percent solids by weight. However, dilute slurry pumping has been questioned in view of, large quantities of contaminated water being recirculated, problems controlling scale buildup and wear, potential for leakage of ash water from dams, for ground water pollution, high cost of large areas required for ash dykes and dam constructions.

The problems are substantially eliminated by preparing ash slurry at high concentration for discharge onto a sloped disposal site where the deposit stabilizes.

Highly concentrated, thick slurry runs slowly over the disposal site after leaving the pipeline without water leakage. Abrasive wear is reduced because of laminar flow and low flow velocity. Dense slurries can be transported in mild steel piping of reduced dia without much wear. Dense ash slurries often avoid the need for an ash dam water reclamation system and return water lines. The ash generally will dry out to form a fairly solid surface unaffected by erosion and not prone to dusting in windy conditions. Energy savings can exceed 50 percent.

The systems are being installed at BALCO Korba and Lanjigarh Orissa.

Advantages:

• No ash retaining dams or bunds need to be built.
• Ash spreads in layers hence, ash mounds requires minimum land.
• Higher concentration hence, low water consumption.
• Lower line sizes.
• Very little release of water at the disposal area through rapid drying.
• No appreciable leachate from the disposal site.