Waste treatment process for removal of contaminants from aqueous, mixed-waste solutions using sequential chemical treatment and crossflow microfiltration, followed by dewatering
First Claim
1. A waste treatment process for removal of contaminants including metals, radionuclides and organic matter from a feed of water containing contaminants including metals, radionuclides and organic matter, comprising the following steps:
- treating said feed of water with a base, a powdered ion-exchange material, sodium carbonate, and a powdered adsorbent to remove contaminants; and
separating suspended solids, produced from the treatment, from said feed by passing said feed through a crossflow microfiltration means.
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Abstract
In processes of this invention aqueous waste solutions containing a variety of mixed waste contaminants are treated to remove the contaminants by a sequential addition of chemicals and adsorption/ion exchange powdered materials to remove the contaminants including lead, cadmium, uranium, cesium-137, strontium-85/90, trichloroethylene and benzene, and impurities including iron and calcium. Staged conditioning of the waste solution produces a polydisperse system of size enlarged complexes of the contaminants in three distinct configurations: water-soluble metal complexes, insoluble metal precipitation complexes, and contaminant-bearing particles of ion exchange and adsorbent materials. The volume of the waste is reduced by separation of the polydisperse system by cross-flow microfiltration, followed by low-temperature evaporation and/or filter pressing. The water produced as filtrate is discharged if it meets a specified target water quality, or else the filtrate is recycled until the target is achieved.
42 Citations
13 Claims
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1. A waste treatment process for removal of contaminants including metals, radionuclides and organic matter from a feed of water containing contaminants including metals, radionuclides and organic matter, comprising the following steps:
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treating said feed of water with a base, a powdered ion-exchange material, sodium carbonate, and a powdered adsorbent to remove contaminants; and separating suspended solids, produced from the treatment, from said feed by passing said feed through a crossflow microfiltration means. - View Dependent Claims (2)
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3. A waste treatment process for removal of contaminants including metals, radionuclides and organic matter from a feed of water containing coarse particles, calcium and contaminants, said contaminants including metals including heavy metals, radionuclides and organic matter, comprising the following steps:
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removing coarse particles suspended in said feed of water by passing said feed through a filter; precipitating metals including heavy metals from said feed of water by the addition of a base; sorbing residual dissolved heavy metals and a portion of any dissolved radionuclides from said feed by adding an ion-exchange material; separating metal precipitates and ion-exchange particles from said feed by a first stage crossflow microfiltration; precipitating calcium and a portion of radioactive strontium from said feed by adding soda; sorbing a portion of radionuclides from said feed by adding an ion-exchange material; separating calcium and strontium precipitates, radionuclides and ion-exchange particles from said feed by a second stage crossflow microfiltration; removing residual radionuclides and organic contaminants from said feed by adding activated carbon and ion-exchange material; separating said organic contaminants from said feed by a third stage crossflow microfiltration. - View Dependent Claims (4, 5)
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6. A waste treatment process for removal of contaminants including metals, radionuclides and organic matter from a feed of water containing coarse particles, calcium and contaminants, said contaminants including metals, radionuclides and organic matter, comprising the following steps:
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precipitating contaminants from said feed of water by adding a base to said feed of contaminated water; sorbing contaminants from said feed of water by adding an ion-exchange material; precipitating calcium and contaminants from said feed by adding soda; adsorbing contaminants from said feed of water by adding a powdered adsorbent; and separating suspended particles, produced by the addition of said base, ion-exchange material, soda, and adsorbent, from said feed of water by passing said feed through a crossflow microfiltration means. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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Specification