CAS Number: 98-50-0 Arsenic. GROUND WATER AND ARSENIC. 1-4-04. STARRING:. Something to think about.
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There’s an extra space before the A.
the Greek word arsenikos
and the latin word arsenicum,
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SHAME ON YOU!!!
4-acre Benton Auto Wreckers site, located several miles southwest of the City of Corvallis on
State Highway 20 in Benton County, Oregon
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Arsenic is a natural element in the earth’s crust.
In the environment, arsenic combines with oxygen, chlorine, and sulfur to form inorganic arsenic compounds.
In animals and plants, arsenic combines with carbon and hydrogen to form organic arsenic compounds.
IARC has reviewed the available data and considers arsenic to be a Group 1 carcinogen.
There are currently 9 general processes
VI. Ion Exchange
VII. Membrane/ Reverse Osmosis
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Coagulation involves the removal of colloidal (0.001 - 100 microns) and settleable (> 100 microns) particles.
Coagulation encompasses all reactions, mechanisms and results in the overall process of particle growth (floc formation) and particle aggregation within a water being treated.
Co—precipitation: incorporation of soluble arsenic species into the metal hydroxide floc.
converts soluble arsenic into insoluble reaction products, allowing separation by sedimentation and/or filtration.
*Precipitation: the formation of insoluble compounds Al(AsO4) or Fe(AsO4)
* Co—precipitation: incorporation of soluble arsenic species into the metal hydroxide floc
* Adsorption: the electrostatic binding of soluble arsenic to the external surfaces of the insoluble metal hydroxides
1.Inclusion: mechanical entrapment of a portion of the solution surrounding the growing particle.
2.Adsorption: the attachment of an impurity onto the surface of a particle or precipitate.
3.Occlusion: A contaminant is trapped in the interior of a particle of precipitate.
4.Solid-solution formation: another type of occlusion where a particle of precipitate becomes contaminated with a different type of particle that precipitates under similar conditions and is formed from ions whose sizes are nearly equal to those of the original precipitate.
Sedimentation is the gravity separation of solids from
liquid by settling. It is generally used in conjunction
Conventional filtration is the separation of solid
particles from water by passing the solution through a medium.
Particles are removed during filtration as a result of any one or
combination of mechanisms: mechanical straining, sedimentation,
flocculation,adsorption and/or biological metabolism (AWWA, 1999).
Adsorption is the accumulation of materials at an interface, the liquid/solid boundary layer.
* oxides (e.g. hydrated ferric oxide, titanium oxide, silicon oxide);
* iron oxide-coated or MnO2-coated sand;
* bauxite, hematite, feldspar;
* clay minerals (e.g. kaolinite, bentonite, Bijoypur clay);
* synthetic anion exchange resins;
* chitin and chitosan;
* bone char;
* cellulose materials (sawdust, newspaper pulp).
Ion exchange is the reversible interchange of ions between the solid and the liquid phase where there is no permanent change in
the structure of the solid. Developed for large-scale applications, ion
exchange is probably not appropriate for small hand‑pumped wells,
but could potentially be used on a village scale in Bangladesh
Membrane separation uses semi-permeable membranes that are
selectively permeable to water and certain solutes to separate
impurities from water
Membranes are able to remove many different kinds of dissolved solids, including arsenic, from water. However, they are usually expensive and therefore are typically considered in applications such as desalination, brackish water conversion and for removal of specific ions, such as arsenic, that are difficult to remove by other means
Biological treatment transforms, stabilizes and/or removes
arsenic by means of microorganisms. Microorganisms, primarily
certain specific bacteria, accomplish this by oxidation/reduction,
mineralization,detoxification or methylation. Critical factors
include energy and carbon source; aerobic, anoxic or anaerobic
conditions; temperature; pH
Deeper Tube Wells
Solar distillation uses the sun's energy to evaporate water, which then recondenses. The process of evaporation and recondensation
separates all chemicals, including arsenic, from the water. In
Bangladesh,where solar energy is plentiful, this approach may be
especially suited for application in crisis areas, and, if cost-
effective approaches can be developed, in rural are as generally.
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West Central Environmental Consultants, Inc Can Provide A Complete Cleanup Plant for Arsenic Treated Wood facilities.
Contaminants:Chromated Copper Arsenate (CCA)
Cost:Full Scale plant capable of treating 100 tons/day of CCA contaminated waste wood will cost around $1,000,000
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Other Applications:Remediation of Metal contaminated soil, sludge and other debris
Operating Cost:It will cost between $120 to $150 /ton for remediation of of CCA contaminated wood in a 100 ton/day plant
Tech Know New Remediation Technologies www.techknow.org
Based on best estimate of average arsenic levels for systems that found arsenic.