A heavy-metal recovery technique that produces no waste streams or sludge
By Mary Page Bailey |
A new remediation approach for industrial heavy-metal waste has been developed by Lewis Environmental Services, Inc. (LES; Pittsburgh, Pa.; www.lesvc.com). The patented Enviro-Clean process adsorbs heavy metals from liquid waste streams onto a bed of specially treated granular activated carbon. Then, when the activated carbon is spent and loaded with heavy metals, the activated carbon is chemically stripped to clean the carbon for reuse and to concentrate the heavy metals in the stripping solution. The solution is then processed in an electrolytic cell where the metals are plated on a cathode. The metals in the stripping solution can be selectively recovered to produce a high-purity metal for sale to third-party refiners.
Capable of treating single- or multi-component waste streams, this process is applicable to a very broad range of metals, including chromium, lead, zinc, cadmium, copper, nickel, silver, iron, mercury, manganese, molybdenum and more. Unlike other metal-removal methods, the Enviro-Clean process is not based on chemical precipitation or regeneration, both of which generate hazardous waste streams that require further treatment. The Enviro-Clean process produces no hazardous waste or sludge, instead resulting in a recyclable…