Heavy metal contamination is one the most common forms of pollution found in
and around industrial sites, landfills, abandoned mining operations, and municipal and agricultural
outfalls. In addition, heavy metals are used in a variety of industrial processes such as steel
production, metal plating and anodizing, automobile and aircraft manufacturing, and general metal
fabrication, just to name a few. Ultimately, all heavy metal wastes exceeding strict EPA environmental
standards require adequate toxicity reduction and proper disposal.
Custom Designed Treatment
There are thousands of documented contaminated sites throughout the US and over 1.3 millions tons
of reportable metal bearing process wastes generated every year. Each situation is unique having
different physical and toxic characteristics. As such, there is also no one single treatment process
or method (magic bean) to address every waste or site situation. However, with expertise in site
remediation and years of chemical treatment experience, SCE, in a teaming arrangements with ADT
Environmental, LLC, has created a diverse array of effective treatment methods custom designed to
achieve desired results for each unique situation.
For example, this versatility allows a mixed waste stream containing a combination of TCLP metals
such as lead, chrome and arsenic to be reduced simultaneously. Customized treatment reagents formulated
to address specific metals can be added to generated wastes without impacting existing in house treatment
processes.
SCE’s heavy metal treatment also provides the highest level of assurance in terms of heavy metal
reduction consistency and longevity. SCE does not promote any one specific reagent or treatment
method but produces the right combination of reagents demonstrated most effective for each waste.
Whether involving phosphate or sulfate based additives, metal valiance reducing reagents, or simple
pozzolonic based materials, SCE’s heavy metal treatment capabilities lend for increased flexibility in
addressing waste handling and disposal.
Our products closely resemble untreated material in most cases with little volume increase and minimal
increase in mass (i.e. 10%). The treated materials may be land filled as a special waste or interred
onsite. Since decontamination wastewaters can be used to dilute the proprietary reagent(s), no waste
streams are generated. SCE does not form monoliths. Therefore, the technology can be applied by using
ex-situ or in-situ methods.
How does SCE's treatment methodology compare to conventional stabilization and other methods using
chemical additives?
1. SCE's heavy metal treatment technology is not tied to any one treatment product, methodology
or means of application and therefore is not restricted to one or two heavy metals or specific
site conditions. SCE's technology can be applied in a variety of ways under most site conditions
addressing one, or a combination of heavy metal contaminates. Organic or inorganic constituents
in soil and other media, including petroleum do not effect SCE's treatment. It also works in a
wide range of pH conditions and is permanent.
2. Additives or reagents applied using SCE's technology adds marginal volumes, (1%- 5%), to the
final waste volume as opposed to standard means (30%-50%). This reduces on site set up, space
requirements and equipment cost, not to mention the significant reduction in off site transportation
and disposal fees
3. SCE's technology is safe, simple and regulatory complaint while converting toxic heavy metals
into a safer, naturally occurring state. SCE successfully performed field treatment for TCLP
arsenic and chrome at one of the most regulatory restrictive sites in the Northwest. SCE's technology
has been demonstrated at a number of EPA test sites and has been accepted in the US Navy's BBA program
as a viable technology option for military site clean ups.
4. SCE provides substantial cost reduction opportunities saving between 30 and 60 percent over
conventional stabilization costs. SCE conducts extensive laboratory testing on every waste stream
prior to application in the field to provide reliable results the first time around.
5. SCE's treatment technology can meet or exceed strict EPA land disposal restrictions in the field
and can interface with state and federal regulatory agencies to provide a complete, compliance
oriented service package to the client.
Process Wastes
K061 is an EPA regulated waste by-product from the primary production of steel in electric furnaces.
K061 can contain a variety of heavy metals including lead, cadmium and chrome. Depending on the
specific process, waste K061 may also contain elevated levels of zinc, copper, and other metals
that can interfere or render pozzolonic or ion specific stabilization methods ineffective. We were
requested to conduct treatability studies on K061 waste from a steel mill and containing high levels
of lead, cadmium, chrome, and zinc. Using treatment formulations that added only 3 percent to the
original waste volume, we successfully reduced TCLP levels to below RCRA as well as below the more
stringent land disposal restrictions for all metals of concern. This on site treatment process allows
for off site disposal at considerably less cost.
| |
Pretreated Totals (ppm) |
Treated TCLP (ppm) |
| Lead |
9,200 |
ND |
| Cadmium |
160 |
ND |
| Chrome |
1900 |
0.11 |
| Zinc |
120,000 |
0.10 |
Soil Contamination
During the 1990s, heavy metal concentrations have been identified in the Spokane River, which empties
Lake Coeur d'Alene and leads to the salmon and trout spawning grounds of the Columbia River system.
Following laboratory bench scale tests a stabilization method was identified for on-site confirmation
of an in-situ technique that would not damage the River's banks. Specially formulated reagents were
applied and testing revealing concentrations below EPA (LDR).
| |
Pretreated Totals (ppm) |
Treated TCLP (ppm) |
| Lead |
57 |
0.15 |
| Arsenic |
25.2 |
Less than 0.1 |
| Zinc |
78.9 |
0.72 |
Waste Stockpiles and Sediments
An EPA superfund located northern California is typical of wood treating facilities that employed CCA
(Copper-Chromium-Arsenate) formulations to reduce biological degradation and insect damage in structural
and decorative timber. Concentrations of leachable arsenic in excess of RCRA clean up standards were
identified in several areas of the plant including the upper 2- 3 feet of soil in the "drip-line" area;
sediments collected in storm water settling basins and soils around and under the pressure retorts used
to force treating solutions into the timber. SCE conducted on site treatment using costumed formulated bulk
reagents adding less than 2 % original waste volume. Treated wastes were then permanently deposited in a
specially designed cell on site.
| |
Pretreated Totals (ppm) |
Treated TCLP (ppm) |
| Arsenic |
278 |
0.15 |
| Chrome |
25.2 |
Less than 0.1 |
List of Treatable Waste Streams
|
Heavy Metal |
Media |
|
Lead |
Soils - tills,
clays, fine sands, coarse sands, loam, silts, etc.
Wastewater Sludge - plumbing fixture mfg., TV tube mfg.
Sediments - river & lake bottoms, settling basins
Mineral processing waste - tailings, media separator bottoms
Battery recycling debris
Primary and Secondary smelter slag
Steel electromelt furnace dust (K061)
Petroleum refinery sludge - K048, K051, K052, tetraethyl lead
Mirror mfg. waste
Target range backstop soils
Automobile recycling "shredder fluff"
Foundry sands
Paint sandblasting debris
Scrap yard soils and storm water runoff basin sediments
Municipal waste incinerator ash
Abrasive mfg. debris |
|
Cadmium
|
Wastewater sludge -
battery mfg.
Wastewater sludge - printed circuit board mfg.
Lead & Zinc ore processing waste
Automobile "shredder" fluff |
|
Arsenic
|
Soils & sediments
at CCA wood treating plants
Veterinary medicine formulation waste.
Ash from thermal destruction of chemical weapons.
K084 sludge |
|
Zinc |
Zinc ore processing
waste
Galvanizing process rinseate sediments |
|
Chromium
|
Soil at chromium
ore staging site
Soil around chrome plating line.
Wastewater treatment sediment at bearing mfg.
Cooling tower basin sediments |
|
Selenium
|
Agricultural runoff
sediment
Ceramic "frit" residue |
|
Antimony
|
Weapons mfg
wastewater sediment |
Several in-situ processing techniques are available depending on topography and near surface soil
conditions. Projects range from little as 300 yd3 treated to a depth of one foot to very large
projects at greater depths. Current capabilities now allow treatment to take place at much greater
depths and in some cases under water tables. In-situ treatment at voluntary remediation and RCRA
sites have not required a Part B RCRA treatment permit and have allowed clients to significantly
expedite regulator approval for onsite treatment when the alternative was excavation and offsite
disposal as hazardous waste.
