# US 5,350,691 A · Method for abandoning an underground storage tank

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- Number: US 5,350,691 A
- Document ID: US5350691A
- Status: Granted
- Kind: A
- Application number: 08/075,326
- Filed: 1993-06-11
- Granted: 1994-09-27
- Earliest claimed: 1991-08-26
- Inventors: Richard C. Hannay; Dudley B. Pate
- Web page: https://patentgrep.com/patent/US5350691A

## CPC

- B09B 3/38: Stirring or kneading
- B09B 3/70: Chemical treatment, e.g. pH adjustment or oxidation (involving an extraction step B09B3/80)
- C12P 1/00: Preparation of compounds or compositions, not provided for in groups C12P3/00 - C12P39/00, by using microorganisms or enzymes
- B09B: DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}

## Abstract

A method of abandoning an underground storage tank including the steps of: removing residuals, if any, from the tank and filling the tank with a mixture which includes water, sand, a binding agent and a material for promoting uniform mixing of said mixture. In one embodiment of the invention, a surfactant is added to reduce the amount of water required by the mixture.

## Claims

### Claim 1

A method of abandoning an underground storage tank in which hydrocarbon substances have been stored comprising the steps of:
a. removing residual substances, if any, from said tank; and
b. completely filling said tank with a mixture which includes water, sand, a binding agent and a material for promoting uniform mixing of said mixture wherein said mixture forms a solid composition with a structural strength of 40 psi to 250 psi.

### Claim 2 (depends on 1)

The method of claim 1 in which said mixture includes a fatty acid alkyl amide surfactant in an amount sufficient to reduce the amount of water required by said mixture.

### Claim 3 (depends on 1)

The method of claim 1 in which said mixture includes a catalyst for said binding agent.

### Claim 4 (depends on 3)

The method of claim 3 in which said catalyst is selected form the group consisting of: triacetin, muriatic acid, citric acid and sodium silica fluoride.

### Claim 5 (depends on 1)

The method of claim 1 in which said material for promoting uniform mixing of said mixture is selected from the group consisting of: fly ash, fumed silica, attapulgite clay, dry flow starch and kiln dust.

### Claim 6 (depends on 1)

The method of claim 1 in which said mixture includes by volume 6% to 23% liquids and 77% to 94% solids.

### Claim 7 (depends on 6)

The method of claim 6 in which said mixture includes by volume approximately 55% to 81% sand.

### Claim 8 (depends on 7)

The method of claim 7 in which said mixture includes by volume approximately 6% to 22% water.

### Claim 9 (depends on 6)

The method of claim 6 in which said material for promoting uniform mixing of said mixture makes up by volume approximately 10% to 18% of said mixture.

### Claim 10 (depends on 1)

The method of claim 1 in which said mixture includes a surfactant and the approximate percentages, by volume, of the following materials: 81% sand, 6.4% water, 10.25% fly ash, 1.5% sodium silicate, 0.15% triacetin.

### Claim 11 (depends on 10)

The method of claim 10 in which said mixture also includes by volume approximately 0.7% metal salts.

### Claim 12 (depends on 1)

The method of claim 1 wherein the step of removing the residual substances includes the step of introducing hydrocarbon devouring microbes into said tank for bio-remediation of any residual hydrocarbon substance in said tank prior to filling of said tank with said mixture.

### Claim 13 (depends on 12)

The method of claim 12 in which said hydrocarbon devouring microbes are allowed to reside in said tank for several days prior to said filling of said tank with said mixture.

### Claim 14 (depends on 1)

The method of claim 1 including the steps of washing said tank with a detergent solution and removing said detergent solution from said tank prior to filling said tank with said mixture.

### Claim 15 (depends on 1)

The method of claim 1 in which said storage tank is made of ferrous material, said mixture including metal salts more noble than said ferrous material to enhance the corrosion of said storage tank.