Method and apparatus for injecting steam into landfills

Abstract

A method of injecting steam into a landfill is provided. The steam enhances methane gas production in the landfill during the anaerobic phase, accelerates decomposition/biodegradation of the organic component of the trash prism during both the aerobic and anaerobic phases, and increases the rate of settlement of the landfill. A method of introducing a gaseous anaerobic fertilizer into the landfill is also provided. The fertilizer accelerates the decomposition/biodegradation of the organic component of the trash prism. A method of reducing the volume of a plastic component of the trash prism is provided, wherein the temperature and pressure of injected steam are raised to a level sufficient to melt plastic. Finally, a method of reducing the volume of a quantity of refuse prior to placing the refuse in a landfill is provided, wherein the refuse is heated to melt a plastic component of the refuse.

What is claimed is:  
     
         1 . A method of enhancing methane gas production in a landfill having a trash prism, accelerating decomposition/biodegradation of an organic component of the trash prism, and increasing a rate of settlement of the landfill, comprising the steps of: 
 providing at least one steam injection well and at least one gas extraction collector;    providing a source of steam;    injecting the steam into the trash prism via the steam injection well; and    extracting methane gas produced by decomposition/biodegradation of organic refuse within the trash prism via the gas extraction collector.    
     
     
         2 . The method of  claim 1 , wherein the steam injection well and the gas extraction collector each comprise push-in screens and risers.  
     
     
         3 . The method of  claim 1 , further comprising the step of determining an ideal location for the steam injection well and gas extraction collector using a piezo-penetrometer test profile.  
     
     
         4 . The method of  claim 1 , wherein the steam injection well and the gas extraction collector are installed using a piezo-penetrometer test rig.  
     
     
         5 . The method of  claim 1 , wherein the source of steam comprises a boiler.  
     
     
         6 . The method of  claim 1 , wherein the source of steam comprises a heat exchanger on a gas flare.  
     
     
         7 . The method of  claim 1 , wherein the source of steam comprises exhaust steam from a power plant.  
     
     
         8 . The method of  claim 1 , wherein the source of steam comprises liquid water from a flooded portion of the landfill that is boiled using heat from a submersible heater.  
     
     
         9 . The method of  claim 1 , further comprising the step of injecting a gaseous anaerobic fertilizer into the landfill.  
     
     
         10 . The method of  claim 9 , wherein the gaseous anaerobic fertilizer comprises ammonia.  
     
     
         11 . The method of  claim 9 , wherein the gaseous anaerobic fertilizer comprises ammonia nitrate.  
     
     
         12 . The method of  claim 1 , further comprising the step of injecting nitrous oxide into the landfill.  
     
     
         13 . The method of  claim 1 , further comprising the step of raising a temperature and a pressure of the steam following substantial completion of the biodegradation/decomposition of the organic component of the trash prism and recovery of substantially all of the methane produced thereby.  
     
     
         14 . The method of  claim 13 , wherein the temperature of the steam is raised to approximately 400° F. to 600° F.  
     
     
         15 . The method of  claim 14 , wherein a valve on the gas extraction collector is opened upon the temperature of the steam reaching approximately 400° F. to 600° F at a midpoint between the steam injection well and the gas extraction collector.  
     
     
         16 . The method of  claim 14 , wherein substantially all of the steam is recovered through the gas extraction collector prior to condensing inside the landfill.  
     
     
         17 . The method of  claim 1 , further comprising the step of placing moisture sensors and temperature sensors within the landfill.  
     
     
         18 . The method of  claim 17 , further comprising the step of monitoring a liquid accumulation on a dense layer below the injection well.  
     
     
         19 . The method of  claim 18 , further comprising the step of reducing an amount of steam injected upon detection of liquid.  
     
     
         20 . The method of  claim 17 , further comprising the step of monitoring movement of the steam through the trash prism using the temperature sensors.  
     
     
         21 . The method of  claim 1 , further comprising the step of monitoring the biodegradation/decomposition of the organic component of the trash prism and an amount of settling between dense layers using a piezo-penetrometer test profile.  
     
     
         22 . The method of  claim 21 , further comprising the step of reducing an amount of steam injected as a volume of the organic component of the trash prism is reduced.  
     
     
         23 . The method of  claim 1 , further comprising the step of monitoring a rate of settling of the landfill using a top deck elevation measurement from a piezo-penetrometer test profile and a survey of the top deck.  
     
     
         24 . The method of  claim 1 , further comprising the step of monitoring a landfill gas at the gas extraction collector.  
     
     
         25 . The method of  claim 1 , wherein the source of steam is a boiler.  
     
     
         26 . The method of  claim 25 , wherein the methane extracted from the landfill is used to fire the boiler.  
     
     
         27 . The method of  claim 1 , wherein the source of steam is a heat exchanger.  
     
     
         28 . The method of  claim 1 , wherein the source of steam is exhaust steam from a power plant.  
     
     
         29 . A method of accelerating decomposition/biodegradation of an organic component of a landfill having a trash prism, and increasing a rate of settlement of the landfill, comprising the steps of: 
 providing at least one air injection well and at least one gas extraction collector;    providing a source of steam;    injecting air and the steam into the trash prism via the air injection well; and    collecting the steam via the gas extraction collector.    
     
     
         30 . The method of  claim 29 , wherein the steam replaces moisture in the landfill that is lost during aerobic degradation.  
     
     
         31 . The method of  claim 30 , wherein a pipe connected to the gas extraction collector transports the steam to another location.  
     
     
         32 . The method of  claim 31 , wherein the steam is transported back to the source of steam.  
     
     
         33 . A method of reducing a volume of a quantity of refuse prior to placing the refuse in a landfill, comprising the steps of: 
 providing a containerized trammel;    placing the refuse in the trammel; and    applying high-temperature and high-pressure steam to the refuse while the trammel is rotated.    
     
     
         34 . The method of  claim 33 , wherein the steam causes a plastic component of the refuse to melt.  
     
     
         35 . The method of  claim 34 , further comprising the step of placing screens inside the trammel to capture melted plastic.  
     
     
         36 . The method of  claim 35 , further comprising the step of removing the screens and recovering the melted plastic.  
     
     
         37 . The method of  claim 33 , further comprising the step of placing the refuse in a landfill.