Iron-Containing Bioreactor & Method for Treating Reducible Compound Residues

Abstract

An iron containing bioreactor for treating explosive compounds and other organics in contaminated surface water is disclosed. The bioreactor can be located either on-ground or in-ground at a location across which contaminated surface water flows. In one configuration the reactor is made up of (i) indigenous microbes, (ii) acetate, (iii) a low density iron-containing bed, and contains anaerobic zones in at least one portion of the flowpath. The reactor reduces the concentration of explosive compounds to below 10 ppb and also maintains this explosive compound reduction level for a period of at least one year without replenishing the microbes or iron.

What is claimed is: 
     
         1 . An iron containing bioreactor for treating explosive compounds and other organics in contaminated surface water, said bioreactor located either on-ground or in-ground at a location across which said contaminated surface water flows, said reactor comprising:
 (i) indigenous microbes,   (ii) acetate,   (iii) a low density iron-containing bed, and   (iv) containing anaerobic zones in at least one portion of the flowpath, wherein said reactor reduces a concentration of said explosive compounds to below 10 ppb and maintains said explosive compound reduction level for a period of at least one year without replenishing said microbes or iron.   
     
     
         2 . The bioreactor of  claim 1  further comprising a liner, said liner forming a cavity within which said microbes, acetate and iron are placed. 
     
     
         3 . The bioreactor of  claim 2  further comprising at least one baffle, said baffle oriented to create an area of the bioreactor upstream of said baffle and an area of the reactor downstream of said baffle. 
     
     
         4 . The bioreactor of  claim 3  comprising a plurality of baffles. 
     
     
         5 . The bioreactor of  claim 2  further comprising at least one lower baffle, said lower baffle oriented to create an area of the bioreactor upstream of said lower baffle and an area of the reactor downstream of said lower baffle, said bioreactor having a vertical height of said cavity, wherein said lower baffle extends upward from a bottom of said cavity and has a height no more than half of the vertical height of said cavity. 
     
     
         6 . The bioreactor of  claim 5  further comprising at least one upper baffle, said upper baffle oriented to create an area of the bioreactor upstream of said upper baffle and an area of the reactor downstream of said upper baffle, said bioreactor having a vertical height of said cavity, wherein said upper baffle extends downward from a top of said cavity and has a height no more than half of the vertical height of said cavity. 
     
     
         7 . The bioreactor of claim six comprising a plurality of lower baffles and upper baffles. 
     
     
         8 . The bioreactor of  claim 2  further comprising a cover layer. 
     
     
         9 . The bioreactor of  claim 2  wherein an operating temperature of the bioreactor is from about 32° F. to about 65° F. 
     
     
         10 . The bioreactor of  claim 1  wherein said reactor reduces said concentration of said explosive compounds to below 5 ppb. 
     
     
         11 . The bioreactor of  claim 1  wherein said low density iron-containing bed further comprises a packing material. 
     
     
         12 . The bioreactor of  claim 11  wherein said packing material is selected from the group consisting of rocks, wood chips, mulch, gravel, stone, peat, sand, activated carbon, biochar and combinations thereof. 
     
     
         13 . The bioreactor of  claim 1  wherein the oxygen-reduction potential, measured in millivolts, in said low density iron-containing bed is less than 0.0 mV. 
     
     
         14 . The bioreactor of  claim 1  wherein said reactor reduces a concentration of said explosive compounds to below 10 ppb and maintains said explosive compound reduction level for a period of at least ten years without replenishing said microbes or iron. 
     
     
         15 . The bioreactor of  claim 1  wherein said low density iron bed is less than about 30% by volume iron. 
     
     
         16 . The bioreactor of  claim 1  wherein said low density iron bed is less than about 10% by volume iron. 
     
     
         17 . A method for removing explosive compounds from contaminated surface water using a bioreactor, said bioreactor located either on-ground or in-ground at a location across which said contaminated surface water flows, said method comprising the steps of:
 (a) providing an iron containing bioreactor with anaerobic zones, said bioreactor comprising (i) indigenous microbes, (ii) acetate (iii) a low density iron-containing bed, and (iv) anaerobic zone in at least one portion of the flowpath.   (b) providing a flow of said contaminated surface water into said bioreactor,   (c) contacting said explosive compounds with said low density iron whereby said iron is reduced,   (d) contacting said reduced iron with said microbes whereby said iron is oxidized, and   (e) repeating steps (c) and (d) such that a concentration of said explosive compounds is lowered to below 10 ppb in the treated surface water, and wherein said explosive compound reduction level is maintained for a period of at least one year without replenishing said microbes or iron.   
     
     
         18 . The method of  claim 17  wherein said bioreactor further comprising a liner, said liner foaming a cavity within which said microbes, acetate and iron are placed. 
     
     
         19 . The method of  claim 18  wherein said bioreactor further comprises at least one baffle, said baffle oriented to create an area of the bioreactor upstream of said baffle and an area of the reactor downstream of said baffle. 
     
     
         20 . The method of  claim 19  wherein said bioreactor has a plurality of baffles. 
     
     
         21 . The method of  claim 18  wherein said bioreactor further comprises at least one lower baffle, said lower baffle oriented to create an area of the bioreactor upstream of said lower baffle and an area of the reactor downstream of said lower baffle, said bioreactor having a vertical height of said cavity, wherein said lower baffle extends upward from a bottom of said cavity and has a height no more than half of the vertical height of said cavity. 
     
     
         22 . The method of  claim 21  wherein said bioreactor further comprises at least one upper baffle, said upper baffle oriented to create an area of the bioreactor upstream of said upper baffle and an area of the reactor downstream of said upper baffle, said bioreactor having a vertical height of said cavity, wherein said upper baffle extends downward from a top of said cavity and has a height no more than half of the vertical height of said cavity. 
     
     
         23 . The method of  claim 22  wherein said bioreactor has a plurality of lower baffles and upper baffles. 
     
     
         24 . The method of  claim 18  wherein said bioreactor further comprises a cover layer. 
     
     
         25 . The method of  claim 18  wherein said bioreactor has an operating temperature from about 32° F. to about 65° F. 
     
     
         26 . The method of  claim 17  wherein said bioreactor reduces said concentration of said explosive compounds to below 5 ppb. 
     
     
         27 . The method of  claim 17  wherein said low density iron-containing bed further comprises a packing material. 
     
     
         28 . The method of  claim 27  wherein said packing material is selected from the group consisting of rocks, mulch, gravel, stone, peat, sand, activated carbon and combinations thereof. 
     
     
         29 . The method of  claim 17  wherein the oxygen-reduction potential, measured in millivolts, in at least one portion of said low density iron-containing bed is less than 0.0 mV. 
     
     
         30 . The method of  claim 17  wherein said reactor reduces a concentration of said explosive compounds to below 10 ppb and maintains said explosive compound reduction level for a period of at least ten years without replenishing said microbes or iron. 
     
     
         31 . The method of  claim 17  wherein said low density iron bed is less than about 30% by volume iron. 
     
     
         32 . The method of  claim 17  wherein said low density iron bed is less than about 10% by volume iron.