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US 4,292,176 AGranted
Use of activated carbon in waste water treating process
AssigneeStandard Oil Company (Indiana)
InventorsJames F. Grutsch, Russell C. Mallatt
Life of this patent
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AssigneeStandard Oil Company (Indiana)
InventorsJames F. Grutsch, Russell C. Mallatt
Estimating the term…
Disclosed is a process for treating waste water through the use of activated carbon. The carbon is generally added to waste water having a pH from about 4 to about 11, and is commonly added after the waste water has undergone primary treatment. Preferred modes of operation comprise using low concentrations of activated carbon having a high surface area and a zeta potential greater than about -10 millivolts. It is also preferred to use activated carbon in conjunction with an activated sludge process having an average sludge age greater than about ten days, especially where the waste water undergoes a pretreatment prior to the activated sludge process to reduce chemical oxygen demand, oil and solids content. Low concentrations of activated carbon based on feed waste water are generally used while maintaining substantially higher carbon concentrations in the process.
In the activated sludge process wherein a first stage contaminated water is contacted with activated sludge for a period of time sufficient to biologically degrade contaminants in the water and in a second stage decontaminated water is separated from the activated sludge, a first portion of said separated sludge being recycled for recontact with the water in the first stage and a second portion of said separated sludge being treated in downstream operations, the improvement comprising pretreating the contaminated water entering the first stage so that the water contains less than about 20 ppm of hydrocarbons and less than about 20 ppm of solids;
In the activated sludge process wherein a first stage contaminated water is contacted with activated sludge for a period of time sufficient to biologically degrade contaminants in the water and in a second stage decontaminated water is separated from the activated sludge, a portion of said separated sludge being recycled for recontact with water in the first stage, the improvement comprising introducing about 1 to about 500 ppm of activated carbon into the water so that the carbon is present in the first or second stages, said carbon having a zeta potential of at least about -10 millivolts.
In a waste water treating process wherein waste water having a pH of from about 4 to about 11 is contacted with activated carbon, the improvement comprising maintaining the zeta potential of the carbon at least about -10 millivolts.
In the activated sludge process wherein a first stage contaminated water is contacted with activated sludge for a period of time sufficient to biologically degrade contaminants in the water and in a second stage decontaminated water is separated from the activated sludge, a portion of said separated sludge being recycled for recontact with water in the first stage, the improvement comprising
In the activated sludge process wherein a first stage contaminated water is contacted with activated sludge for a period of time sufficient to biologically degrade contaminants in the water and in a second stage decontaminated water is separated from the activated sludge, a first portion of said separated sludge being recycled for recontact with the water in the first stage and a second portion of said separated sludge being treated in downstream operations, the improvement comprising pretreating the contaminated water entering the first stage so that the water contains less than about 20 ppm of dispersed hydrocarbons and less than about 20 ppm of solids;
In the activated sludge process wherein a first stage contaminated water is contacted with activated sludge for a period of time sufficient to biologically degrade contaminants in the water and in a second stage decontaminated water is separated from the activated sludge, a portion of said separated sludge being recycled for recontact with water in the first stage, the improvement comprising
Dependencies are inferred from the claim text.