Patent Publication Number: US-2006005749-A1

Title: Process for washing and sorting solid residues generated from solid wastes incinerator

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
      The present invention relates to a processing process and more particularly, to a process for washing and sorting solid residues generated from the wastes incinerator so as to obtain homogenous and aggregate material for reuse.  
      Following development of different industries and increase of consumption, waste material from factories, homes, offices, etc., are continuously produced, resulting in deterioration of the environment. Therefore, it is necessary to reduce the production of waste material and to reclaim useful material from waste material. Burning solid waste by means of incinerator is the procedure of reducing the size of waste material and the policy of environmental protection. About 15 to 20% of ash will generated from incinerator. Where 10% is so call bottom ash, and 90% is bottom ash roughly. Solid residues from burn incinerators are commonly buried in the earth, not for use.  
      U.S. Pat. Nos. 5,308,368; 5,890,663; 5,906,321; 5,992,776; 4,737,356 refer a combination of methods including crushing and sorting processes and adding of stabilized reagent for immobilization of useful materials from solid residues. However, there are odor and potential of pollutant leachate problem need to take care.  
      The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide a process for washing and sorting solid residues generated from the solid wastes incinerator, which is practically to obtain homogenous and aggregate material from the solid residues for different applications. To achieve this and other objects of the present invention, the process for processing solid residual material comprising the steps of (a) feeding the solid residual material to process through a feeder to a sorting unit comprising a plurality of vibration screens of different meshes for sorting the solid residual material into coarse particle size residual material, medium-size residual material, and fine particle size residual material; (b) reclaiming the coarse particle size residual material; (c) using a magnetic separator to remove ferrous metal material and then using a crusher to crush the remaining residual material and then delivering the crushed material to the sorting unit for sorting again; (d) carrying the fine particle size residual material by water through a water channel to washing unit and keeping the fine particle size residual material in contact with water for about 1 minutes or more so as to let toxic substance be leached in water, and then removing the washed fine particle size residual material from the washing unit to a dewater equipment to dry for drying into homogenous and stabilized aggregate material for use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the first embodiment of the present invention.  
       FIG. 2  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the second embodiment of the present invention.  
       FIG. 3  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the third embodiment of the present invention.  
       FIG. 4  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the fourth embodiment of the present invention.  
       FIG. 5  is a water quality analysis table of the drainage water according to the first embodiment of the present invention.  
       FIG. 6  is a material property analysis of the washed aggregate material after treatment of the process according to the first embodiment of the present invention.  
       FIG. 7  is the water quality analysis table of the drainage water according to the third embodiment of the present invention.  
       FIG. 8  is the material property analysis of the washed aggregate material according to the third embodiment of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIG. 1 , solid waste material  10  from a solid waste incinerator is processed through a series of crushing and screening processes, and thus solid residual material  1  is generated. The process of the present invention is to wash and assort solid residual material  1  thus generated. Solid residual material  1  is then delivered to a feeder  2 , which comprises a material flow control that controls solid residual material output capacity. A conveyer delivers solid residual material  1  is then delivered from the feeder  2  to a sorting unit  3 . The sorting unit  3  comprises a plurality of vibration screens of different meshes for sorting solid residual material  1  into three different groups under the presence of a pressured washing flow of water, namely, coarse particle size residual material  31 , medium-size residual material  32 , fine particle size residual material  33 . Coarse particle size residual material  31  is reclaimed for further use. Medium-size residual material  32  is delivered to a magnetic separator  4  where ferrous metal material and remaining residual material is crushed through a crusher  5  and then delivered to the sorting unit  3  for treatment. Fine particle size residual material  33  is carried by water through a water channel to a washing unit  6 . The washing unit  6  can be a watermill, centrifugal washing device, non-mechanical type immersion tank, or any other washing devices. According to this embodiment, the washing unit  6  is a watermill comprised of a water channel and waterwheel When entered the washing unit  6 , fine particle size residual material  33  is maintained in contact with water for about 1 minutes or more, enabling harmful substance to be solved in water. The waterwheel carries washed fine particle size residual material from the water channel to a dewater equipment  8  to dry homogenous stabilized aggregate material  331  for use in different constructions.  
       FIG. 2  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the second embodiment of the present invention. This embodiment is substantially same as the first embodiment shown in  FIG. 1  with the exception that crushed material generated from the crusher  5  is screened through a separator  30  into fine particle size residual material  33 ′, which is then delivered to the washing unit  6  for treatment. Further, in either of the aforesaid first and second embodiments, the ratio by weight between water and residual material to wash is preferably at 0.6 up.  
      Further, stabilized reagent may be added to water to immobilize heavy metal during washing in the washing unit  6 . stabilized reagent can be any of a variety of salt compounds of low solubility to heavy metal such as sulfide, hydroxide, organic polymers, inorganic polymers.  
       FIG. 3  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the third embodiment of the present invention. According to this embodiment, solid waste material  10  from a solid waste incinerator is processed through a series of crushing and screening processes, and thus solid residual material  1  is generated. Solid residual material  1  thus generated is then delivered to a feeder  2 , which comprises a material flow control that controls solid residual material output capacity. A conveyer delivers solid residual material  1  is then delivered from the feeder  2  to a sorting unit  3 . The sorting unit  3  comprises a plurality of vibration screens of different meshes for sorting solid residual material  1  into three different groups under the presence of a pressured washing flow of water, namely, coarse particle size residual material  31 , medium-size residual material  32 , fine particle size residual material  33 . Coarse particle size residual material  31  is reclaimed for further use. Medium-size residual material  32  is delivered to a magnetic separator  4  where ferrous metal material is removed from medium-size residual material  32  and remaining residual material is crushed through a crusher  5  and then delivered to the sorting unit  3  for treatment. Fine particle size residual material  33  is carried by water through a water channel to a washing unit  6 . The washing unit  6  can be a watermill, centrifugal washing device, non-mechanical type immersion tank, or any other washing devices. According to this embodiment, the washing unit  6  is a watermill comprised of a water channel and waterwheel When entered the washing unit  6 , fine particle size residual material  33  is maintained in contact with water for about 1 minutes or more, enabling harmful substance to be solved in water. The waterwheel carries primarily washed fine particle size residual material from the water channel to a water channel connected to a second washing unit  7 , for enabling primarily washed fine particle size residual material to be carried by a running flow of water to the second washing unit  7  for secondary water washing. The second washing unit  7  is a watermill comprised of a water channel and a waterwheel. When entered the second washing unit  7 , primarily washed fine particle size residual material is maintained in contact with water for about 1 minutes or more. The waterwheel of the second washing unit  7  carries secondarily washed fine particle size residual material from the water channel to a dewater equipment  8  to dry homogenous stabilized aggregate material  331  for different applications.  
       FIG. 4  is a flow chart of the process for washing and sorting solid residues generated from the solid wastes incinerator according to the fourth embodiment of the present invention. This embodiment is substantially same as the third embodiment shown in  FIG. 3  with the exception that crushed material generated from the crusher  5  is screened through a separator  30  into fine particle size residual material  33 ′, which is then delivered to the washing unit  6  for treatment. Further, in either of the aforesaid third and fourth embodiments, the ratio by weight between water and residual material to wash at the washing unit  6  as well as at the second washing unit  7  is preferably at 0.6 minimum.  
      Further, stabilized reagent may be added to water to immobilize heavy metal during washing in the washing unit  6  and the second washing unit  7 . stabilized reagent can be any of a variety of salt compounds of low solubility to heavy metal such as sulfide, hydroxide, organic polymers, inorganic polymers.  
       FIG. 5  is a water quality analysis table of the drainage water according to the first embodiment of the present invention. As illustrated, under the condition of the ratio between water and material (m3/tone) to be 1, the drainage water exhibited the values of: pH 12.2, COD 560 mg/l, Cl (Chloride) 1200 mg/l, Pb (Lead) 2.5 mg/l; under the condition of the ratio between water and material (m3/tone) to be 2, the drainage water exhibited the values of: pH 11.3, COD 360 mg/l, Cl (Chloride) 800 mg/l, Pb (Lead) 1.5 mg/l.  
       FIG. 6  is a material property analysis of the washed aggregate material after treatment of the process according to the first embodiment of the present invention. As illustrated, under the condition of the ratio between water and material (m3/tone) to be 1, aggregate material exhibited the values of: Chlorate 0.11%, Pb (Lead) 1.87 mg/l subject to TCLP (Toxicity Characteristic Leaching Procedure); under the condition of the ratio between water and material (m3/tone) to be 2, aggregate material exhibited the values of: Chlorate 0.07%, Pb (Lead) 1.88 mg/l subject to TCLP.  
       FIG. 7  is a water quality analysis table of the drainage water according to the third embodiment of the present invention. As illustrated, under the condition of the ratio between water and material (m3/tone) to be 1, the drainage water from the washing unit exhibited the values of: pH 12.2, COD 560 mg/l, Cl (Chloride) 1200 mg/l, Pb (Lead) 2.5 mg/l; under the condition of the ratio between water and material (m3/tone) to be 2, the drainage water from the second washing unit exhibited the values of: pH 11.3, COD 360 mg/l, Cl (Chloride) 800 mg/l, Pb (Lead) 1.5 mg/l; under the condition of the ratio between water and material (m3/tone) to be 2, the drainage water from the washing unit exhibited the values of: pH 11.1, COD 270 mg/l, Cl (Chloride) 700 mg/l, Pb (Lead) 1.1 mg/l, under the condition of the ratio between water and material (m3/tone) to be 3, the drainage water from the second washing unit exhibited the values of: pH 11.1, COD 160 mg/l, Cl (Chloride) 600 mg/l, Pb (Lead) 0.6 mg/l.  
       FIG. 8  is a material property analysis of the washed aggregate material after treatment of the process according to the third embodiment of the present invention. As illustrated, under the condition of the ratio between water and material (m3/tone) at the washing unit to be 1, aggregate material exhibited the values of: Chlorate 0.11%, Pb (Lead) 1.87 mg/l subject to TCLP; under the condition of the ratio between water and material (m3/tone) at the second washing unit to be 2, aggregate material exhibited the values of: Chlorate 0.07%, Pb (Lead) 1.88 mg/l subject to TCLP; under the condition of the ratio between water and material (m3/tone) at the washing unit to be 2, aggregate material exhibited the values of: Chlorate 0.05%, Pb (Lead) 0.61 mg/l subject to TCLP; under the condition of the ratio between water and material (m3/tone) at the second washing unit to be 3, aggregate material exhibited the values of: Chlorate 0.04%, Pb (Lead) 0.10 mg/l subject to TCLP.  
      As indicated above, the process of the present invention effectively removes bad smell solid residual material from a solid waste incinerator, and leaches toxic substances from solid residual material. Homogenous stabilized aggregate material generated from solid residual material after treatment of the process according to the present invention is applicable for different applications.