Remediation of metal contaminants with hydrocarbon-utilizing bacteria

Abstract

Methods and apparatus are disclosed for remediating metal contaminants using hydrocarbons which stimulate the growth of hydrocarbon-utilizing bacteria. The metal contaminants may include heavy metals such as arsenic, antimony, beryllium, cadmium, chromium, copper, lead, mercury, iron, manganese, magnesium, radium, nickel, selenium, silver, thallium and zinc. The hydrocarbon may include alkanes, alkenes, alkynes, poly(alkene)s, poly(alkyne)s, aromatic hydrocarbons, aromatic hydrocarbon polymers and aliphatic hydrocarbons. Butane is a particularly suitable hydrocarbon which stimulates the growth of butane-utilizing bacteria. Remediation may occur in-situ or ex-situ, and may occur under aerobic, anaerobic or dual aerobic/anaerobic conditions. Examples of applications include the remediation of heavy metals, the remediation of arsenic impacted surface water, groundwater and/or soil, the remediation of acid mine drainage, and the treatment of spent metal plating solutions.

1 . A system for remediating a metal contaminant comprising means for treating the metal contaminant with alkane-utilizing bacteria in the presence of an alkane comprising butane, ethane and/or propane.  
   
   
       2 . The system of  claim 1 , wherein the alkane comprises butane.  
   
   
       3 . The system of  claim 2 , wherein the butane is provided as a butane substrate comprising butane as the most prevalent compound of the substrate.  
   
   
       4 . The system of  claim 2 , wherein the butane is provided as a butane substrate comprising at least about 10 weight percent butane.  
   
   
       5 . The system of  claim 2 , wherein the butane is provided as a butane substrate comprising at least about 50 weight percent butane.  
   
   
       6 . The system of  claim 2 , wherein the butane is provided as a butane substrate comprising at least about 90 weight percent butane.  
   
   
       7 . The system of  claim 2 , wherein the butane is provided as a butane substrate comprising at least about 99 weight percent n-butane.  
   
   
       8 . The system of  claim 1 , wherein the alkane comprises ethane.  
   
   
       9 . The system of  claim 1 , wherein the alkane comprises propane.  
   
   
       10 . The system of  claim 1 , wherein the metal contaminant comprises at least one heavy metal.  
   
   
       11 . The system of  claim 10 , wherein the at least one heavy metal comprises arsenic, antimony, beryllium, cadmium, chromium, copper, lead, mercury, iron, manganese, magnesium, radium, nickel, selenium, silver, thallium and/or zinc.  
   
   
       12 . The system of  claim 1 , wherein the metal contaminant comprises arsenic.  
   
   
       13 . The system of  claim 1 , wherein the metal contaminant comprises selenium.  
   
   
       14 . The system of  claim 1 , wherein the metal contaminant comprises chromium.  
   
   
       15 . The system of  claim 1 , wherein the metal contaminant comprises a radioactive metal.  
   
   
       16 . A remediation system for treating a metal contaminant comprising: 
 a source of an alkane substrate comprising butane, ethane and/or propane; and    at least one injector in flow communication with the source of the alkane substrate and the metal contaminant.    
   
   
       17 . The system of  claim 16 , wherein the alkane comprises butane.  
   
   
       18 . The system of  claim 17 , wherein the butane is provided as a butane substrate comprising butane as the most prevalent compound of the substrate on a weight percentage basis.  
   
   
       19 . The system of  claim 17 , wherein the butane is provided as a butane substrate comprising at least about 10 weight percent butane.  
   
   
       20 . The system of  claim 17 , wherein the butane is provided as a butane substrate comprising at least about 50 weight percent butane.  
   
   
       21 . The system of  claim 17 , wherein the butane is provided as a butane substrate comprising at least about 90 weight percent butane.  
   
   
       22 . The system of  claim 17 , wherein the butane is provided as a butane substrate comprising at least about 99 weight percent n-butane.  
   
   
       23 . The system of  claim 16 , wherein the alkane comprises ethane.  
   
   
       24 . The system of  claim 16 , wherein the alkane comprises propane.  
   
   
       25 . The system of  claim 16 , wherein the metal contaminant comprises at least one heavy metal.  
   
   
       26 . The system of  claim 25 , wherein the at least one heavy metal comprises arsenic, antimony, beryllium, cadmium, chromium, copper, lead, mercury, iron, manganese, magnesium, radium, nickel, selenium, silver, thallium and/or zinc.  
   
   
       27 . The system of  claim 16 , wherein the metal contaminant comprises arsenic.  
   
   
       28 . The system of  claim 16 , wherein the metal contaminant comprises selenium.  
   
   
       29 . The system of  claim 16 , wherein the metal contaminant comprises chromium.  
   
   
       30 . The system of  claim 16 , wherein the metal contaminant comprises a radioactive metal.  
   
   
       31 . The system of  claim 16 , further comprising means for supplying oxygen to the metal contaminant.  
   
   
       32 . The system of  claim 31 , wherein the oxygen is supplied in the form of air.  
   
   
       33 . The system of  claim 31 , wherein oxygen is supplied in the form of substantially pure oxygen.  
   
   
       34 . The system of  claim 31 , wherein the oxygen is supplied to the metal contaminant continuously.  
   
   
       35 . The system of  claim 31 , wherein the oxygen is supplied to the metal contaminant intermittently.