Soil-Based Flow-Through Rhizosphere System For Treatment Of Contaminated Water And Soil

Abstract

A process for constructing a soil-based rhizosphere flow-through system to break down contaminants in contaminated water. The process includes the steps of: providing plants planted in soil in a test bioreactor, the plants providing a rhizosphere; exposing the rhizosphere to the contaminated water, extracting microorganisms from the rhizosphere following their exposure to the contaminated water: preparing a microbial suspension from the extract; subjecting the microbial suspension to growth conditions to increase the concentration of the microorganism, thereby preparing a soil conditioner; adding the soil conditioner to soil in a contained area having a water flow inlet and outlet; and planting a plurality of plants in the soil, the plants being of the same species as the plants of the test bioreactor.

1 . A process for preparing a soil conditioner to increase the rate of decontamination of contaminated water or contaminated soil, the process comprising
 a) providing a rhizosphere;   b) exposing the rhizosphere to the contaminated water;   c) extracting microorganisms from the rhizosphere after step b);   d) preparing a microbial suspension from the extract; and   e) subjecting the microbial suspension to growth conditions to increase the concentration of the microorganisms, thereby preparing the soil conditioner.   
     
     
         2 . The process of  claim 1 , wherein step b) comprises generating a flow of the contaminated water across the rhizosphere, the flow entering at an inlet and exiting at an outlet. 
     
     
         3 . The process of  claim 2 , wherein the flow of the contaminated water is conducted for a period of about 4 to about 8 weeks. 
     
     
         4 . The process of  claim 2  or  3 , further comprising testing of outflow from the outlet to identify one or more metabolic products of one or more contaminants present in the contaminated water. 
     
     
         5 . The process of any one of  claims 1  to  4 , further comprising measuring the amount of microorganisms present in the extract in the microbial suspension. 
     
     
         6 . The process of any one of  claims 1  to  5 , further comprising measuring the amount of microorganisms present in the soil conditioner, wherein a plate count of at least about 10 6  counts/mL indicates that the soil conditioner is suitable for use in treatment of a soil bed in construction of the soil-based flow-through rhizosphere system. 
     
     
         7 . The process of any one of  claims 1  to  6 , wherein the rhizosphere is of a wetland plant. 
     
     
         8 . The process of  claim 7 , wherein the wetland plant is selected from the group consisting of  Phragmites australis, Arundo donax  L.,  Neyraudia reynaudiana, Phalaris arundinacea, Glyceria maxima, Elegia tectorum, Thamnochortus insignis , a species of the genus  Calamagrostis , a species of the genus  Sparganium , and a species of the genus  Typha.    
     
     
         9 . The process of any one of  claims 1  to  8 , wherein steps a) and b) are conducted in a test bioreactor having a volume of about 10 L to about 50 L. 
     
     
         10 . The process of any one of  claims 1  to  9 , wherein the contaminated water comprises organic contaminants. 
     
     
         11 . The process of any one of  claims 1  to  10 , wherein the microbial suspension comprises microorganisms originally present in the contaminated water and microorganisms originally present in the rhizosphere. 
     
     
         12 . A process for constructing a soil-based rhizosphere flow-through system to break down contaminants in contaminated water, the process comprising:
 a) providing plants planted in soil in a test bioreactor, the plants providing a rhizosphere;   b) exposing the rhizosphere to the contaminated water;   c) extracting microorganisms from the rhizosphere after step b);   d) preparing a microbial suspension from the extract;   e) subjecting the microbial suspension to growth conditions to increase the concentration of the microorganisms, thereby preparing a soil conditioner;   f) adding the soil conditioner to soil in a contained area having a water flow inlet and outlet; and   g) planting a plurality of plants in the soil, the plants being of the same species as the plants of step a).   
     
     
         13 . The process of  claim 12 , wherein step b) comprises generating a flow of the contaminated water across the rhizosphere, the flow entering at an inlet and exiting at an outlet. 
     
     
         14 . The process of  claim 13 , wherein the flow of the contaminated water is conducted for a period of about 4 to about 8 weeks. 
     
     
         15 . The process of any one of  claim 13  or  14 , further comprising testing of outflow from the outlet to identify one or more metabolic products of one or more contaminants present in the contaminated water. 
     
     
         16 . The process of any one of  claims 12  to  15 , further comprising measuring the amount of microorganisms present in the extract in the microbial suspension. 
     
     
         17 . The process of any one of  claims 12  to  16 , further comprising measuring the amount of microorganisms present in the soil conditioner, wherein a plate count of at least about 10 5  counts/mL indicates that the soil conditioner is suitable for use in treatment of a soil bed in construction of the soil-based flow-through rhizosphere system. 
     
     
         18 . The process of any one of  claims 12  to  17 , wherein the rhizosphere is of a wetland plant. 
     
     
         19 . The process of  claim 18 , wherein the wetland plant is selected from the group consisting of  Phragmites australis, Arundo donax  L.,  Neyraudia reynaudiana, Phalaris arundinacea, Glyceria maxima, Elegia tectorum, Thamnochortus insignis , a species of the genus  Calamagrostis , a species of the genus  Sparganium , and a species of the genus  Typha.    
     
     
         20 . The process of any one of  claims 12  to  19 , wherein steps a) and b) are conducted in a test bioreactor having a volume of about 10 L to about 50 L. 
     
     
         21 . The process of any one of  claims 12  to  20 , wherein the contaminated water comprises organic contaminants. 
     
     
         22 . The process of any one of  claims 12  to  21 , wherein the microbial suspension comprises microorganisms originally present in the contaminated water and microorganisms originally present in the rhizosphere. 
     
     
         23 . A soil-based flow-through rhizosphere system for breaking down contaminant organic compounds in contaminated water, the system comprising:
 a) a contained area comprising soil treated with a soil conditioner prepared according to the process of any one of  claims 1  to  11  and planted with plants of the same species as the rhizosphere, the contained area having a water flow inlet and a flow outlet,   b) a tank for holding the contaminated water before entry of the contaminated water into the contained area; the tank in flow communication with the flow inlet; and   c) a retention pond in communication with the flow outlet.   
     
     
         24 . The system of  claim 23  further comprising a soak-away discharge pond in flow communication with the retention pond to allow discharge of treated water into the environment. 
     
     
         25 . The system of  claim 23  or  claim 24  further comprising a recirculation line in flow communication between the retention pond and the water flow inlet. 
     
     
         26 . The system of any one of  claims 23  to  25  wherein the contained area is a container configured to provide predominately horizontal flow of the contaminated water from the flow inlet to the flow outlet. 
     
     
         27 . The system of  claim 26  wherein the container comprises a soil depth of between about 0.4 m to about 0.5 m to provide a predominately aerobic soil environment. 
     
     
         28 . The system of any one of  claims 23  to  25  wherein the contained area is a container configured to provide predominately vertical flow of the contaminated water from the flow inlet to the flow outlet. 
     
     
         29 . The system of  claim 28 , wherein the container comprises a soil depth of between about 0.8 m to about 1.0 m to provide soil having both a predominately aerobic soil environment closer to the soil surface and a predominately anaerobic soil environment closer to the bottom of the container. 
     
     
         30 . A process for breaking down contaminant compounds in contaminated soil, the process comprising:
 a) isolating contaminated water from the contaminated soil;   b) providing a rhizosphere,   c) exposing the rhizosphere to the contaminated water;   d) extracting microorganisms from the rhizosphere after step c);   e) preparing a microbial suspension from the extract;   f) subjecting the microbial suspension to growth conditions to increase the concentration of the microorganisms, thereby preparing a soil conditioner; and   g) treating the contaminated soil with the soil conditioner.   
     
     
         31 . The process of  claim 30 , wherein step c) comprises generating a flow of the contaminated water across the rhizosphere, the flow entering at an inlet and exiting at an outlet. 
     
     
         32 . The process of  claim 31 , wherein the flow of the contaminated water is conducted for a period of about 4 to about 8 weeks. 
     
     
         33 . The process of any one of  claim 31  or  32 , further comprising testing of outflow from the outlet to identify one or more metabolic products of one or more contaminants present in the contaminated water. 
     
     
         34 . The process of any one of  claims 30  to  33 , further comprising measuring the amount of microorganisms present in the extract in the microbial suspension. 
     
     
         35 . The process of any one of  claims 30  to  34 , further comprising measuring the amount of microorganisms present in the soil conditioner, wherein a plate count of at least about 10 6  counts/mL indicates that the soil conditioner is suitable for use in treatment of the contaminated soil. 
     
     
         36 . The process of any one of  claims 30  to  35 , wherein the rhizome is of a wetland plant. 
     
     
         37 . The process of  claim 36 , wherein the wetland plant is selected from the group consisting of  Phragmites australis, Arundo donax  L.,  Neyraudia reynaudiana, Phalaris arundinacea, Glyceria maxima, Elegia tectorum, Thamnochortus insignis , a species of the genus  Calamagrostis , a species of the genus  Sparganium , and a species of the genus  Typha.    
     
     
         38 . The process of any one of  claims 30  to  37 , wherein step c) is conducted in a test bioreactor having a volume of about 10 L to about 50 L. 
     
     
         39 . The process of any one of  claims 30  to  38 , wherein the contaminated water comprises organic contaminants. 
     
     
         40 . The process of any one of  claims 30  to  39 , wherein the microbial suspension comprises microorganisms originally present in the contaminated soil and microorganisms originally present in the rhizosphere.