Mar 15 2011
Beneficial Reuse of Coal Ash Using HCR’s High Pressure Plate & Frame Filter Press (Sludge Dewatering)
Coal Ash is a byproduct of burning coal. The coal ash contains arsenic, mercury, cadium, selenium, chromium, lead, nickel, and several other toxins. Coal Combustion Residuals (CCRs) are fly ash, bottom ash, boiler slag, and flue gas desulfurization materials. In the past, fly ash was generally released into the atmosphere, but it is now required to be filtered out by pollution-control equipment. There are more than 136 million tons of Coal Combustion Residuals generated per year. Roughly 34 % are placed in landfills or stored in coal power plants in the United States. Some beneficial use for Coal Combustain Residuals is raw feed for cement clinker, concrete, grout, soil-modification, mineral filler, snow and ice traction control, blasting grit and abrasives, roofing granules, soil amendment, agriculture and much more.
Proposed Regulatory Changes to Coal Combustion Residuals suggest that the EPA would list residuals as special wastes subject to regulation under subtitle C of RCRA, when destined for disposal in landfills or surface impoundments. These changes could drastically affect some continued beneficial reuse. Currently, the EPA supports “safe and environmentally appropriate” beneficial uses: cement, asphalt, and concrete, but there is a growing concern over non-encapsulated uses of CCRs. Changes to waste classification and reuse options could transform CCRs from a valuable byproduct to a costly liability if not managed proactively.
That’s why the importance of waste minimalization of coal and fly ash is so critical. Handex Industrial Service’s(HIS) sludge dewatering process achieves volume reductions of up to 80%. HIS’s High Pressure Plate and Frame Filter Press treatment solutions are widely regarded as the most cost effective for many RCRA Hazardous Waste Streams. This liquid/solid separation technology yields the greatest volume reduction while generating the minimum quantity of waste residue, and returns recyclable sludge byproducts including oils or metals which can be further reclaimed, refined or recycled. In many cases, our clients find that the value of the raw materials returned to the plant pays for the cost of the sludge dewatering service.
Sludge dewatering is the separation of water and other liquids from semi solids or sludge. By dewatering the sludge, the volume of waste requiring off site transportation and disposal or recycling is reduced and can provide recovery of valuable residuals. Handex Industrial Services offers an innovative technique utilizing a High Pressure Plate & Filter Press that can produce Filter Cake with up to 70% solids by weight. It is the highest % solids by weight (driest) of all dewatering technologies and it yields a volume reduction of up to 90%. Plate and Frame Filter Press applications are optimum for meeting Paint Filter Tests required for by Sanitary and Secure Landfills and over the road transportation.
High Pressure is achieved with a Piston driven Diaphragm Pump. This type of processing is generally used on sludges where the solids are disposed of as a hazardous waste by High Temperature Incineration or Secure Landfill and the highest volume reduction is desired. In addition, high pressure is effective in breaking out byproducts that are entrained in the sludge. For many waste streams, steam enhancement is utilized to change the physical characteristics of the sludge prior to dewatering. Steam enhanced pre-treatment has proven cost effective for Oily Sludges where under ambient temperatures dewatering is difficult and would require higher quantities of conditioning agents.
References:
Click here for more info on the EPA’s Proposed Coal Combustion Residuals Rule
Click here for the EPA’s info on Coal Ash
Click here for more info on HIS Industrial Sludge Dewatering
Click here to find an HCR office in your area
Or ask an HCR Professional Today!
Ted Orndorff, General Manager
609-409-6999 ext 1204
Mike Scaringella, Director of Sales & Marketing
352-735-1800 ext 1500
