Biological solids processing

Abstract

A method of processing biological solids includes blending a sludge with calcium oxide and delivering the blended sludge and calcium oxide to a pressurized container; injecting, into the blended sludge and calcium oxide in the pressurized container, an additive capable of exothermic reactions with the calcium oxide; regulating pH in the pressurized container to produce class A biological solids from the sludge; and pumping the blended sludge, calcium oxide, and additive from the pressurized container to a reactor. A system used for this process include sources of calcium oxide and biological solids, an additive injector, and a pressurized reactor.

1 . A process for treating pathogen-containing sludge of biological solids, the process comprising:
 blending a sludge with an alkaline product;   delivering the sludge and the alkaline product to a pressurized container;   injecting, into the pressurized container, a gaseous or liquid additive;   mixing the additive with the sludge and the alkaline product;   delivering the sludge, the alkaline product, and the additive into a temperature and pressure controlled reactor;   regulating pH and temperature in the reactor from an exothermic reaction produced by the sludge, the alkaline product, and the additive to reduce pathogens in the sludge, creating a reacted sludge;   removing ammonia from the reacted sludge with a vapor and odor recovery mechanism and a water scrubber; and   delivering the sludge to a recovery station to recover end products from the system.   
     
     
         2 . The process of  claim 1 , and further comprising:
 blending an acid with the sludge and the alkaline product before delivering the sludge and the alkaline product to the pressurized container, wherein the acid is sulfamic acid.   
     
     
         3 . The process of  claim 1 , wherein ammonia is scrubbed from the sludge with an air blower and is dissolved into a spent additive selected from the group consisting of spent sulfuric acid, spent nitric acid, spent phosphoric acid, and combinations thereof. 
     
     
         4 . The process of  claim 1 , wherein ammonia is scrubbed from the sludge with an air blower and is dissolved into water. 
     
     
         5 . The process of  claim 1 , wherein the alkaline product is selected from the group consisting of calcium oxide, fly ash, bed ash, calcium carbonate, low grade lime, kiln dust, gypsum, and combinations thereof. 
     
     
         6 . The process of  claim 1 , wherein the sludge is between 50% and 95% water by weight. 
     
     
         7 . The process of  claim 1 , wherein the additive is selected from the group consisting of carbon dioxide, phosphoric acid, sulfuric acid, nitric acid, sulfamic acid, carbonic acid, hydronium ions, and combinations thereof. 
     
     
         8 . The process of  claim 1 , wherein the blending and delivering occur via a delivery mechanism selected from the group consisting of a belt conveyor, a conveyer, a drag chain, a feed screw, a hopper, a twin-screw auger, a positive displacement pressure pump and combinations thereof. 
     
     
         9 . A system for treating pathogen-containing sludge of biological solids, the system comprising:
 a first delivery mechanism that mixes the sludge and an alkaline product;   a pressurized container that receives and temporarily holds the sludge and the alkaline product;   an injector that injects an additive into the pressurized container with the sludge and the alkaline product;   a temperature and pressure controlled reactor in which the alkaline product and the additive produce an exothermic reaction that reduces pathogens within the sludge; and   a vapor and odor recovery mechanism that removes ammonia containing vapor from the sludge.   
     
     
         10 . The system of  claim 9 , and further comprising:
 a recovery station that receives the sludge after processing; and   a second delivery mechanism that transports the sludge, the alkaline product, and the additive from the pressurized container to the reactor, from the reactor to the vapor and odor recovery mechanism, and from the vapor and odor recovery mechanism to the recovery station.   
     
     
         11 . The system of  claim 10 , wherein the recovery station recovers fertilizer products from the exothermic reaction between the alkaline product and the additive. 
     
     
         12 . The system of  claim 9 , wherein ammonia is scrubbed from the sludge by the vapor and odor recovery mechanism with an air blower and is dissolved into water. 
     
     
         13 . The system of  claim 9 , wherein ammonia is scrubbed from the sludge by the vapor and odor recovery mechanism with an air blower and is dissolved into a spent additive selected from the group consisting of spent sulfuric acid, spent nitric acid, spent phosphoric acid, and combinations thereof. 
     
     
         14 . The system of  claim 9 , wherein the alkaline product is selected from the group consisting of calcium oxide, fly ash, bed ash, calcium carbonate, low grade lime, kiln dust, gypsum, and combinations thereof. 
     
     
         15 . The system of  claim 9 , wherein the sludge is between 50% and 95% water by weight. 
     
     
         16 . The system of  claim 9 , wherein the additive is selected from the group consisting of carbon dioxide, phosphoric acid, sulfuric acid, nitric acid, sulfamic acid, carbonic acid, hydronium ions, and combinations thereof. 
     
     
         17 . The system of  claim 9 , wherein the additive is injected into the pressurized container as a liquid or a gas. 
     
     
         18 . The system of  claim 9 , wherein the first delivery mechanism and the second delivery mechanism are selected from the group consisting of a belt conveyor, a conveyer, a drag chain, a feed screw, a hopper, a twin-screw auger, a positive displacement piston pump, and combinations thereof. 
     
     
         19 . A system for treating pathogen-containing sludge of biological solids, the system comprising:
 a first delivery mechanism that receives and mixes the sludge, an alkaline product, and an acid, wherein the first delivery mechanism is enclosed;   a pressurized container that receives and temporarily holds the sludge, the alkaline product, and the acid;   an injector that injects a liquid or gaseous additive into the pressurized container;   a mixing mechanism in the pressurized container to combine the additive with the sludge, the alkaline product, and the acid;   a second delivery method to move the sludge, the alkaline product, the acid, and the additive through the system;   a temperature and pressure controlled reactor in which the alkaline product, the additive, and the sludge produce an exothermic and pH altering reaction that reduces pathogens within the sludge;   a vapor and odor recovery mechanism to remove ammonia containing vapors from the pathogen-reduced sludge;   a water scrubber that scrubs and collects ammonia-containing products from the pathogen reduced sludge and the ammonia containing vapors; and   a recovery station to recover end products from the system.