Process and system for treating waste from the production of energetics

Abstract

A waste stream from energetics processing is treated using a pre-filter having media, preferably sand, and a metal that has a reducing potential, preferably elemental iron (Fe 0 ). The pre-filter is connected to a zero-valent metal column reactor. The waste stream is pumped through the pre-filter to trap solids and deoxygenate it, then enters the reactor and is subjected to a reducing process. Most of the Fe 0 is transformed to the ferrous ion (Fe +2 ), added to the resultant product, and fed to a continuous stirred tank reactor (CSTR) in which Fenton oxidation occurs. This product is then sent to a sedimentation tank and pH-neutralized using a strong base such as sodium hydroxide (NaOH). The aqueous portion is drawn off and the sludge pumped from the sedimentation tank. Both tanks are monitored and controlled to optimize required additives, while monitoring of pressure drop across the pre-filter and column reactor establishes replacement requirements.

We claim:  
     
         1 . A system for treating a waste stream that may contain suspended and colloidal solids, comprising: 
 a pre-filter containing a zero-valent metal and media suitable for filtering    at least some of said solids from said waste stream;    a zero-valent metal column reactor operably connected to said pre-filter,    wherein after said waste stream is treated therein and a first treated waste stream is output;    a first vessel in which initial contents include an oxidizer to be combined    with said first treated waste stream,    wherein said contents of said first vessel are adjusted to optimize the amount of said oxidizer and a metal ion resultant from processing said waste stream with said zero-valent metal in said zero-valent metal column reactor,    wherein said contents of said first vessel are further adjusted to optimize the pH of said contents of said first vessel, and    wherein said contents of said first vessel are stirred as part of treating said contents prior to output as a second treated waste stream; and    a second vessel for accepting said second treated waste stream as at least part of its contents,    wherein said second treated waste stream is pH-neutralized,    wherein said contents of said second vessel are further adjusted to optimize pH of said contents of said second vessel, and    wherein said second treated waste stream is permitted to settle prior to drawing off at least one final product suitable for reuse.    
     
     
         2 . The system of  claim 1  in which said waste stream results from operations involved with the handling of energetic materials.  
     
     
         3 . The system of  claim 2  in which said energetic materials are composed of constituents selected from the group consisting essentially of TNT, RDX, HMX, nitroglycerin (NG), and constituents and combinations thereof.  
     
     
         4 . The system of  claim 1  in which said filter media is a naturally occurring material  
     
     
         5 . The system of  claim 4  in which said naturally occurring material is sand.  
     
     
         6 . The system of  claim 1  in which said filter media is manmade.  
     
     
         7 . The system of  claim 1  in which said metal is selected from the group consisting of: iron, tin, aluminum, zinc, magnesium, nickel, palladium, platinum, and combinations thereof.  
     
     
         8 . The system of  claim 7  in which said metal is predominantly elemental iron (Fe 0 ), wherein, upon reaction of said elemental iron with said waste stream, at least part of said elemental iron is converted to the ferrous ion (Fe +2 ) and combined with said first treated waste stream.  
     
     
         9 . The system of  claim 1  in which said pre-filter is a replaceable cartridge.  
     
     
         10 . The system of  claim 1  in which said zero-valent metal column reactor is vented to reduce accumulation of gasses that may result from reactions therein.  
     
     
         11 . The system of  claim 1  further comprising a mix control module,  
       wherein automated control of the characteristics of said contents of said first and second vessels is accomplished via said mix control module,  
       wherein said mix control module at least monitors and controls the pH of each of said first and second vessels, and  
       wherein said mix control module controls the amount of said metal ion and said oxidizer in said first vessel.  
     
     
         12 . The system of  claim 1  further comprising an impeller mixer for use in said first vessel.  
     
     
         13 . The system of  claim 1  in which said first vessel is a continuously stirred tank reactor (CSTR).  
     
     
         14 . The system of  claim 1  in which said oxidizer is hydrogen peroxide (H 2 O 2 ).  
     
     
         15 . The system of  claim 1  in which said second vessel is a pH-neutralizing and sedimentation tank,  
       wherein the pH of said second treated waste stream is neutralized within the range of 6.0-8.0 by adding a base, and  
       wherein any said suspended solids within said second treated waste stream are permitted to settle, forming sludge.  
     
     
         16 . The system of  claim 15  in which said base comprises at least some sodium hydroxide (NaOH).  
     
     
         17 . The system of  claim 15  further comprising at least one sludge pump for emptying said sedimentation tank of sludge.  
     
     
         18 . The system of  claim 1  in which said first vessel is positioned lower than said zero-valent metal column reactor thus enabling gravity feed of said first treated waste stream from said zero-valent metal column reactor, and further positioning said second vessel at a position lower than said first vessel thus enabling gravity feeding of said second treated waste stream to said second vessel.  
     
     
         19 . A method for treating a waste stream containing at least some highly oxidized suspended and colloidal solids, comprising: 
 physically filtering at least some of said solids in a pre-filter;    establishing a reducing environment for removing oxygen via use of at    least one zero-valent metal as a reducing agent,    wherein the output of said physical filtering and reducing environment is a first treated waste stream;    subjecting said first treated waste stream to a Fenton oxidation reaction in    a first vessel,    wherein said Fenton oxidation reaction is monitored and controlled, and wherein the output of said Fenton oxidation reaction is a second treated waste stream; and    pH-neutralizing said second treated waste stream in a second vessel prior    to reclaiming at least a portion of said second output waste stream's    constituents;    wherein said second waste stream is permitted to settle in a tank to precipitate any remaining said solids in sludge.    
     
     
         20 . The method of  claim 19  in which said solids comprise at least one energetic material.  
     
     
         21 . The method of  claim 20  in which said energetic material is selected from the group consisting of: TNT, RDX, HMX, nitroglycerin (NG), and constituents and combinations thereof.  
     
     
         22 . The method of  claim 19  in which said metal is selected from the group consisting of: iron, tin, aluminum, zinc, magnesium, palladium, nickel, platinum, and combinations thereof.  
     
     
         23 . The method of  claim 22  in which said metal is predominantly elemental iron (Fe 0 ),  
       wherein, upon reaction of said elemental iron with said waste stream, at least part of said elemental iron is converted to the ferrous ion (Fe +2 ) and combined with said first treated waste stream.  
     
     
         24 . The method of  claim 19  in which said pH neutralizing is accomplished by adding a base.  
     
     
         25 . The method of  claim 24  in which said base is at least some sodium hydroxide (NaOH).  
     
     
         26 . The method of  claim 19  in which said sludge is pumped from said tank.  
     
     
         27 . The method of  claim 19  in which at least one of said reclaimed constituents is water suitable for reuse.  
     
     
         28 . The method of  claim 19  in which said first vessel is positioned lower than said zero-valent metal column reactor thus enabling gravity feed of said first treated waste stream from said first vessel, and further providing said second vessel at a position lower than said first vessel thus enabling gravity feeding of said second treated waste stream to said second vessel.  
     
     
         29 . The method of  claim 19  further comprising optimizing performance of said system by monitoring and controlling: 
 pH of each of said first and second vessels;  
 amount of said oxidizer in said first vessel; and  
 amount of said metal ion in said first vessel.  
 
     
     
         30 . A processing plant that incorporates a system for remediating a waste stream containing at least some suspended and colloidal solids, the system comprising: 
 a pre-filter containing a zero-valent metal and media suitable for filtering    at least some of said solids from said waste stream;    a zero-valent metal column reactor operably connected to said pre-filter,    wherein after said waste stream is treated therein and a first treated waste stream is output;    a first vessel in which initial contents include an oxidizer to be combined with said first treated waste stream,    wherein said contents of said first vessel are adjusted to optimize the amount of said oxidizer and a metal ion resultant from processing said waste stream with said zero-valent metal in said zero-valent metal column reactor,    wherein said contents of said first vessel are further adjusted to optimize the pH of said contents of said first vessel, and    wherein said contents of said first vessel are stirred as part of treating said contents prior to output as a second treated waste stream; and    a second vessel for accepting said second treated waste stream as at least part of its contents,    wherein said second treated waste stream is pH-neutralized,    wherein said contents of said second vessel are further adjusted to optimize pH of said contents of said second vessel, and    wherein said second treated waste stream is permitted to settle prior to drawing off at least one final product suitable for reuse.