 Elastomeric composition |
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| Production of a liquid separation module |
| What is claimed is: 1. A method of producing a liquid separation module of a spiral type, having a ... |
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| Spiral-wound membrane with improved permeate carrier |
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| Process for recycling laden fluids |
| OF THE INVENTION Referring to the drawing, the system for the method of recycle of explosive laden ... |
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| Preparation of aqueous emulsion |
| It has now been found that the above-mentioned objects can be attained by employing a modified PVA ... |
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| Heteropolymer acrylic latices and textiles treated therewith |
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| Hardenable compositions |
| We claim: 1. A hardenable composition which comprises (i) a poly(carboxylic acid) selected from the ... |
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| Sludge control and decant system |
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| Method of making asymmetric cellulose triacetate membranes |
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| Use of raw manganese nodules for oxidation leaching of reductively roasted manganese nodules |
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Method and apparatus for bioremediation of mixed hazardous wastes
| Details |
Inventors: Hunter, Robert M.; Stewart, Frank M.;
Assignee:
Primary Examiner: Lithgow; Thomas M.
Assistant Examiner:
Attorney, Agent or Firm: Hunter; Robert M.
A method and apparatus for bioremediation of mixed hazardous waste is discussed. The method and apparatus can be used for treatment of a liquid or slurry hazardous waste stream (e.g., industrial wastewater or sludge) or for treatment of contaminated groundwater. Removal of the following constituents is possible: (1) aromatic hydrocarbons, such as benzene, toluene, ethylbenzene, xylenes, phenols and cresols, (2) halogenated (e.g., chlorinated) hydrocarbons, such as tetrachloroethylene, trichloroethylene, 1,1,1-trichloroethane and similar xenobiotics, (3) heavy metals, such as copper, lead, zinc, lead, mercury, cadmium, and chromium, (4) acids, such as sulfuric acid and nitric acid, and (5) salts, such as sulfates and nitrates. One embodiment of the invention involves the steps of denitrification (e.g., nitrate reduction), sulfate reduction, methanogenesis and aerobic respiration. Other embodiments delete the denitrification, sulfate-reduction or aerobic respiration steps. In a preferred embodiment, at least a portion of the denitrification and/or sulfate-reduction steps occur in a suspended continuous culture reactor under kinetic control, while the methanogenesis may occur in a biofilm (e.g., in a packed bed reactor or in situ underground.) Reductive dechlorination, control of pH, energy conservation and control of air pollution are accomplished. |
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DETAILED DESCRIPTION OF THE INVENTION Reference is now made to FIG.
1 which is a highly schematic block diagram illustrating a first preferred embodiment of the invention, the dashed lines representing possible variations in the process.
Mixed hazardous waste 1 is the primary input to the process.
Mixed hazardous waste means aromatic hydrocarbons and/or halogenated hydrocarbons, heavy metals, acids and salts.
Examples of aromatic hydrocarbons include benzene, toluene, ethylbenzene, xylenes, phenols and cresols.
Examples of halogenated hydrocarbons include tetrachloroethylene (PCE), trichloroethylene (TCE), and 1,1,1-trichloroethane (TCA).
Examples of heavy metals include copper, lead, zinc and mercury.
Examples of acids include nitric acid, sulfuric acid and hydrochloric acid.
Examples of salts include sodium nitrate, sodium sulfate and sodium chloride.
A first preferred embodiment of the method and apparatus which is appropriate for processing a mixed waste stream involves an initial denitrifying step, an intermediate sulfate reduction step and a subsequent methanogenic step.
A fourth, aerobic step may also be included.
Mixed hazardous waste 1 is moved sequentially through the process by means of gravity or pump 19.
In the first process step, biological denitrification occurs in first reactor 2.
Conditions are created whereby nitrate (or a nitrogenous oxide formed from it by reduction) serves as the terminal electron acceptor.
Oxygen is excluded so as to create an anoxic environment.
In most cases, if the waste stream does not contain nitric acid, addition of sodium nitrate 3 (with the nitrate (NO.
sub.
3) concentration of the reactor controlled by a nitrate-specific electrode) is necessary.
If they are not present in the waste stream, certain trace elements such as molybdenum, copper, iron and manganese are provided as they are required for denitrifiers to produce necessary enzymes.
From reaction stoichiometries presented in the report referenced above, the following nitrate requirements are predicted if addition of a supplemental electron acceptor is necessary:
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Nitrate requirement
Moles of NO
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Liquid Purification 
