Metals removal technologies

T0207 Doe Run Company, TERRAMET Heavy-Metal Removal Technology... 

Neither of the Clyde Engineering metals removal technologies are currently commercially available however, Clyde Engineering Service is willing to sell the patent (U.S. 4,530,763) for one of the technologies (personal correspondence, Robert Clyde, Clyde Engineering, 1/17/97). No full-scale application has been completed for either technology. 

Acid Drainage Prevention and Heavy Metal Removal Technologies... 

Metals removal is the primary function of the entire CMP waste treatment system. All of the unit operations installed upstream of the metals removal step exist only to prepare the waste stream for metals removal. Therefore, it is critical to properly select the metals removal technology since each type of technology may require different pretreatment steps that could increase the overall cost of the system or provide varying degrees of effectiveness. It is imperative to fully understand the composition of the CMP wastewater to be treated and to provide the treatment system with a waste stream with little variability. 

Microbial leaching of metals from ores is a promising adjunct to more aggressive metal recovery technologies (77), but is generally achieved by oxidative processes that generate very acidic waters. It seems unlikely that similar approaches will be of much value in removing contaminant metals and metalloids from soils. 

Electrokinetics. Electrokinetics is a tested technology that has been used for over half a century to dewater and stabilize soils, and has recently been investigated for in situ use at hazardous waste sites (23). Primarily used for metals removal, the technology utilizes an electrical field to generate a flow and concentration gradient in porous and semiporous soils. 

Heavy Metals Removal. Heavy metals should be removed prior to biological treatment or use of other technologies which generate sludges to avoid comingling metal sludges with other, nonhazardous sludges. 

In spite of a few minor operating problems, the DSHS tests appeared to have been successful. All materials, pallets, carbon, and DPE suit material were reduced to the size specified for feeding to the SCWO system the metal removal devices appear to have performed well, and fugitive dust appears to have been controlled. The size reduction of the DPE suit material was of special interest because the technology for heavy polymeric composites is comparatively new. 

T0507 Membrane Technology and Research, Inc., VaporSep Membrane Recovery System T0509 Metal-Based Permeable Reactive Barriers—General T0511 Metals Removal Via Peat—General... 

T0160 Chemfix Technologies, Inc., Chemfix Solidification/Stabilization Technology T0162 Chemical Precipitation of Metals—General T0170 Clyde Engineering, Service Metals Removal... 

Activated alumina is an ex situ contaminant removal technology that extracts metals from liquid and airstreams by adsorption. It is often used as a polishing treatment in conjunction with... 

HPT Research, Inc., has developed the ionic state modification (ISM) process for the treatment of acid mine drainage (AMD). ISM is an ex situ treatment technology that uses magnets, electricity, and proprietary chemical to precipitate heavy metals, remove sulfate ions, and neutralize acidity from AMD and industrial wastewaters. The end products of the process are a metal hydroxide sludge, a calcium sulfate sludge, and treated liquid effluent. The vendor claims that the metal hydroxide sludge may have some value as an ore, the calcium sulfate may be used as an agricultural additive to soils, and the liquid effluent is free of metal contamination and has low sulfate concentrations. 

Metals removal via peat is an in situ, passive treatment technology being developed to treat groundwater contaminated with heavy metals and radionnclides. Bench-scale tests indicate that peat may be an inexpensive and effective material for trapping metals. 

The Unipnre Environmental, Unipnre process technology is a unique iron co-precipitation method for removal of heavy metals from waste streams or groundwater. It can act as a primary metal-removal system or as a polishing step to an existing treatment system. The reactor mod-nle replaces the nentrahzation tank in a conventional wastewater treatment system. The process prodnces solids that are extremely insolnble in water and mild acid solutions. 

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