Bioremediation system and method

• US 5,258,303 A
• Filed: 08/12/1991
• Issued: 11/02/1993
• Est. Priority Date: 08/12/1991
• Status: Expired due to Fees

• Current Assignee: Alfred T. Francis
• Original Assignee: Alfred T. Francis
• Inventors: Stenger, Raymond C.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): JASTRZAB, KRISANNE MARIE
• Application Number:
  US07/743,907
• Time in Patent Office: 813 Days
• Field of Search: 435/262, 435/311, 435/299, 435/313, 435/315, 422/184, 210/170, 210/603, 210/747
• US Class Current: 435/262
• CPC Class Codes: B09C 1/10 microbiologically, biologically or by using enzymes

Abstract

An apparatus and method to clean chlorinated hydrocarbon contaminated soils with a bioremediation system is provided. Treatment beds about one-half acre in size are provided with a gravel base on an impervious film layer. A woven polyethylene membrane is laid on the gravel base with a sand layer in between the membrane and the soil layer to be treated. An aqueous treating liquid containing selective microorganisms is sprinkled on the top surface of the soil layer. Exit gases from the bioreactor are released at zero pressure through perforated pipes laid in the base aggregate layer.

Claims

1. An apparatus to clean a particulate carrier contaminated with biodegradable chemical compounds comprising:

(a) bed means to contain a carrier contaminated with at least one biodegradable chemical compound having an atmospherically exposed surface on top of a layered bed, said layered bed comprising;

(i) impervious retaining means at the bottom of the bed to prevent any liquid from escaping from the bed, and

(ii) a base layer disposed on the impervious retaining means comprising an aggregate,

(b) bioreactor means to hold and propagate a supply of microorganism means comprising microorganisms to break down and digest the biodegradable chemical compound contaminants and to bring these microorganism means into intimate contact with liquid and gaseous biodegradable chemical compound contaminants, the bioreactor means comprising a vapor vent to issue vapors and a liquid outlet means to issue a treating liquid comprising microorganisms,

(c) a multiplicity of parallel aligned first perforated tubing laid in the base layer,

(d) pump means to draw a vacuum on the first perforated tubing and transport fluid from the base layer to the bioreactor means,

(e) a multiplicity of parallel second perforated tubing lengths laid in the base layer, wherein the lengths of second perforated tubing are of sufficient length and of sufficient porosity to reduce the pressure of the vent vapors to zero,

(f) first feed line means fluid flow connecting the second perforated tubing with the vapor vent,

(g) (f) sprinkling means to spread the treating liquid over the exposed surface of the carrier, and

(h) (g) second feed line means fluid flow connecting the liquid outlet means with the sprinkling means.

2. The apparatus of claim 1 wherein the layered bed further comprises:

(a) membrane means disposed on the base means to prevent fine particle size material from entering the base layer, and

(b) separation layer means disposed on the membrane means to provide a porous layer, to aid in liquid dispersion between the layers, and to separate the carrier contaminated with biodegradable chemical compounds from the membrane means.

3. The apparatus of claim 1 wherein the bioreactor means comprises:

(a) mixing means to prepare an aqueous mixture of microorganisms and to feed the mixture to,

(b) bioreactor column means to propagate the microorganisms and to bring the microorganisms into intimate contact with the fluid from the base layer, and

(c) distribution means to receive fluid from the bioreactor column means, provide controllable back pressure to the bioreactor column means, and to distribute vapors to the first feed line means and liquid to the second feed line means.

4. The apparatus of claim 1 wherein the first length of perforated tubing is of sufficient porosity that the vacuum drawn on that tubing by the pump means is sufficient to draw air into the tubing as well as the treating liquid.

5. An apparatus to clean a particulate carrier contaminated with biodegradable chemical compounds comprising:

(a) bed means to expose a carrier contaminated with at least one biodegradable chemical compound with an atmospherically exposed surface on top of a layered bed comprising;

(i) impervious retaining means at the bottom of the bed to prevent any liquid from escaping from the bed, and

(ii) a base layer disposed on the impervious retaining means comprising aggregate,

(b) bioreactor means to hold and propagate a supply of microorganism means comprising microorganisms to break down and digest the biodegradable chemical compound contaminants and to bring these microorganism means into intimate contact with liquid and gaseous biodegradable chemical compound contaminants, the bioreactor means comprising a vapor vent to issue vapors and a liquid outlet means to issue a treating liquid comprising microorganisms,

(c) a multiplicity of parallel aligned first perforated tubing laid in the base layer,

(d) pump means to draw a vacuum on the first perforated tubing and transport fluid from the base layer to the bioreactor means,

(e) first feed line means fluid flow connecting the vapor vent with second perforated tubing laid parallel with the first perforated tubing in the base layer, wherein the lengths of second perforated tubing are of sufficient length and of sufficient porosity to reduce the pressure of the vent vapors to zero,

(f) second feed line means fluid flow connecting the liquid outlet means with a sprinkling means to spread the treating liquid over the exposed surface of the carrier, and

(g) third feed line means fluid flow connecting the first perforated tubing to pump means to the bioreactor means.

6. A system to clean soil contaminated with biodegradable chemical compounds comprising:

(a) a layered bed means to hold soil contaminated with biodegradable chemical compounds disposed with an atmospherically exposed surface on top of a layered bed the layered bed comprising;

(i) impervious retaining means at the bottom of the bed to prevent any liquid from escaping from the bed,

(ii) a base layer disposed on the impervious retaining means comprising stone granules,

(iii) membrane means disposed on the base means to prevent fine particle size material from entering the base layer, and

(iv) separation layer means disposed on the membrane means to provide a porous layer, to aid in liquid dispersion between the layers, and to separate the soil contaminated with biodegradable chemical compounds from the membrane means,

(b) bioreactor means to hold and propagate a supply of microorganism means comprising microorganisms to break down and digest the biodegradable chemical compound contaminants and to bring these microorganism means into intimate contact with liquid and gaseous biodegradable chemical compound contaminants, the bioreactor means comprising a vapor vent to issue vapors and a liquid outlet means to issue a treating liquid comprising microorganisms,

(c) a multiplicity of parallel aligned first perforated tubing laid in the base layer,

(d) pump means to draw a vacuum on the first perforated tubing and transport fluid from the base layer to the bioreactor means,

(e) first feed line means fluid flow connecting the first perforated tubing to pump means to the bioreactor means,

(f) second feed line means fluid flow connecting the vapor vent with second perforated tubing laid parallel with the first perforated tubing in the base layer, wherein the second length of perforated tubing is of sufficient length and of sufficient porosity to reduce the pressure of the vent vapors to zero, and

(g) third feed line means fluid flow connecting the liquid outlet means with a sprinkling means to spread the treating liquid over the exposed surface of the soil.

7. A method to clean a particulate carrier contaminated with biodegradable chemical compounds comprising:

(a) preparing a bed comprising;

(i) laying an impervious retaining means at the bottom of the bed to prevent any liquid from escaping from the bed,

(ii) laying a base layer disposed on the impervious retaining means comprising a coarse aggregate,

(iii) laying membrane means disposed on the base means to prevent fine particle size material from entering the base layer, and

(iv) laying separation layer means disposed on the membrane means to provide a porous layer, to aid in liquid dispersion between the layers, and to separate the carrier contaminated with biodegradable chemical compounds from the membrane means,

(b) spreading the particulate carrier contaminated with at least one biodegradable chemical compound with an exposed surface on top of the layered bed,

(c) holding, propagating, and supplying microorganism means comprising microorganisms in a vessel to break down and digest the biodegradable chemical compound contaminants,

(d) bringing these microorganism means into intimate contact with liquid and gaseous biodegradable chemical compound contaminants,

(e) issuing a treating liquid comprising microorganisms,

(f) sprinkling the treating liquid over the exposed surface of the carrier,

(g) drawing a vacuum on a multiplicity of parallel aligned first perforated tubing laid in the base layer,

(h) transporting fluid from the base layer to the vessel,

(i) venting vapors from the vessel, and

(j) flowing the vented vapors out to second perforated tubing laid parallel with the first perforated tubing in the base layer to reduce the pressure of the vent vapors to zero.

8. A method to clean a particulate carrier contaminated with biodegradable chemical compounds, comprising:

(a) providing a bed means containing the carrier contaminated with biodegradable chemical compounds having an atmospherically exposed surface on top of a layered bed, said layered bed comprising;

(i) impervious retaining means at the bottom of the bed to prevent any liquid from escaping from the bed,

(ii) a base layer disposed on the impervious retaining means comprising aggregate,

(iii) membrane means disposed on the base means to prevent fine particle size material from entering the base layer, and

(iv) separation layer means disposed on the membrane means to provide a porous layer, to aid in liquid dispersion between the layers, and to separate the carrier contaminated with biodegradable chemical compounds from the membrane means,

(b) providing bioreactor means, the bioreactor means comprising a vapor vent to issue vapors and a liquid outlet means to issue a treating liquid comprising microorganisms,

(c) laying a multiplicity of parallel aligned first perforated tubing laid in the base layer,

(d) connecting pump means to draw a vacuum on the first perforated tubing and transport fluid from the base layer to the bioreactor means,

(e) connecting first feed line means for fluid flow connecting the first perforated tubing to pump means to the bioreactor means,

(f) connecting second feed line means for fluid flow connecting the vapor vent with second perforated tubing laid parallel with the first perforated tubing in the base layer, wherein the second perforated tubing is of sufficient length and of sufficient porosity to reduce the pressure of the vent vapors to zero, and

(g) connecting third feed line means for fluid flow connecting the liquid outlet means with a sprinkling means to spread the treating liquid over the exposed surface of the carrier.

(h) holding, propagating and supplying microorganism means in the bioreactor means, which microorganisms break down and digest the biodegradable chemical contaminants,

(i) bringing said microorganism means into contact with liquid and gaseous biodegradable chemical compound contaminants,

(j) issuing a treating liquid comprising microorganisms,

(k) sprinkling the treating liquid over the exposed surface of the carrier,

(l) drawing a vacuum on the multiplicity of parallel aligned first perforated tubing,

(m) transporting fluid from the base layer to the bioreactor means,

(n) venting vapors from the bioreactor means,

(o) flowing the vented vapors out to the second perforated tubing.