Method of combining wastewater treatment and power generation technologies

Abstract

Applicant's preferred embodiment utilizes municipal wastewater effluent to replenish a depleted geothermal field. Condensate produced by expanding steam produced in the geothermal field through a steam turbine-generator may be pooled with cooked water collected from said field, and then directed through a penstock from a higher elevation to a lower elevation where further energy is extracted through a traditional hydroelectric turbine-generator. The cooked water and condensate may be treated to produce potable water and/or distributed for public consumption either before or after being directed to the hydroelectric turbine-generator. The effluent is pumped up to the geothermal field during off-peak periods of electric consumption, and the hydroelectric generation is accomplished during periods of peak electric demand. A fraction of the effluent may be used as cooling water for the steam turbine-generator and its associated condenser before injection into the geothermal field. At least a portion of the pipeline to transport the wastewater effluent is preferably routed along an undisturbed riverbed and/or through an excavated tunnel.

What is claimed is:  
     
         1 . A method of employing wastewater effluent in power generation comprising the steps of: 
 delivering wastewater effluent to a geothermal steam field,    injecting said effluent into said field;    collecting steam from said field;    extracting energy in the form of electricity from said steam by expansion in a steam turbine-generator system thereby producing condensate; and    distilling at least a fraction of said condensate to produce potable water.    
     
     
         2 . A method according to    claim 1    further comprising the step of: 
 pumping said effluent to said geothermal steam field through a piping system.  
 
     
     
         3 . A method according to    claim 2    wherein: 
 said pumping is performed in at least one stage.  
 
     
     
         4 . A method according to    claim 1    further comprising the step of: 
 directing at least a fraction of said condensate to a lower elevation by force of gravity, through a hydroelectric turbine-generator, extracting energy in the form of electricity.  
 
     
     
         5 . A method according to    claim 4    further comprising the step of: 
 directing other than said fraction of said condensate to a holding pond.  
 
     
     
         6 . A method according to    claim 4    further comprising the step of: 
 treating said condensate exiting said hydroelectric turbine-generator to produce potable water.  
 
     
     
         7 . A method according to    claim 1    further comprising the steps of: 
 distilling cooked water collected from said field; and  
 directing at least a fraction of said cooked water to a lower elevation by force of gravity, through a hydroelectric turbine-generator, extracting energy in the form of electricity.  
 
     
     
         8 . A method according to    claim 7    further comprising the step of: 
 treating said cooked water exiting said hydroelectric turbine-generator to produce potable water.  
 
     
     
         9 . A method according to    claim 2    wherein: 
 at least a portion of said pumping system is routed along an undisturbed riverbed.  
 
     
     
         10 . A method according to    claim 2    wherein: 
 at least a portion of said piping system is routed through a utili-tunnel.  
 
     
     
         11 . A method according to    claim 1    further comprising the step of: 
 distributing said potable water for public consumption.  
 
     
     
         12 . A method of employing wastewater effluent in power generation comprising the steps of: 
 delivering wastewater effluent to a geothermal steam field, said delivery being accomplished by at least one stage of pumping said effluent through a piping system;    injecting said effluent into said field;    collecting steam from said field;    extracting energy in the form of electricity from said steam by expansion in a steam turbine-generator system thereby producing condensate;    re-injecting a fraction of said condensate into said geothermal steam field; and    distilling a fraction of said condensate producing potable water.    
     
     
         13 . A method according to    claim 12    further comprising the step of: 
 directing a fraction of said condensate to a lower elevation by force of gravity in a penstock through a hydroelectric turbine-generator, extracting energy in the form of electricity.  
 
     
     
         14 . A method according to    claim 12    wherein: 
 said pumping of said effluent takes place during off-peak periods of electricity consumption; and  
 said hydroelectric generation is accomplished during peak periods of electricity consumption.  
 
     
     
         15 . A method according to    claim 12    further comprising the step of: 
 distributing said potable water for public consumption.  
 
     
     
         16 . A method according to    claim 12    wherein: 
 at least a portion of said pumping system is routed along an undisturbed riverbed.  
 
     
     
         17 . A method according to    claim 12    wherein: 
 at least a portion of said piping system is routed through a utili-tunnel.  
 
     
     
         18 . A method of employing wastewater effluent in power generation comprising the steps of: 
 delivering wastewater effluent to a geothermal steam field;    injecting said effluent into said field into at least one existing steam well which has been substantially exhausted of geothermal steam;    collecting steam from said field; and    extracting energy in the form of electricity from said steam by expansion in a steam turbine-generator system.    
     
     
         19 . A method according to    claim 18    further comprising the step of: 
 pumping said effluent to said geothermal steam field through a piping system.  
 
     
     
         20 . A method according to    claim 18    wherein: 
 the step of injecting said effluent comprises injecting said effluent into a plurality of wells which have been substantially exhausted of geothermal steam.