Abstract:
A system and process are provided for the disinfection of sewage sludge or solids without the addition of chemicals such as chlorine etc. or/and reverse osmosis. The treated sludge or solids can be deposited on landfills or used as fertilizer.

Description:
BACKGROUND OF THE INVENTION 
     Presently sludge or solids of sewage or other sources contaminated with viruses, bacteria, parasites or fungi are treated with high doses of chlorine and require considerable treatment time. The present invention includes a decoagulation process and an ozone disinfection process requiring no chemical addition. 
     The disinfection of sewage sludge or solids is a worldwide problem and difficult problem to control, but is solved with the present invention. The process of the present invention is applicable to any volume of sludge or solids and can be applied as adjunct to any sewage treatment process. 
     After treatment in the system of the present invention, the disinfected sludge or solids can usually be deposited on landfills or used as fertilizer on farmland. 
     SUMMARY OF THE INVENTION 
     The present invention provides an effective disinfection of sewage sludge or solids without the addition of chemicals or the use of membranes or reverses osmosis. 
     Specifically, the present invention consists of a dilution and decoagulation vessel and process. The sludge or solids are entered into the dilution and decoagulation vessel and is diluted with 8 or 10 parts of water to 1 part of sludge or solids. The dilution ratio is determined in pilot tests and may require less or slightly more addition of water. A decoagulation agent is then added, if required, to suspend the sludge or solids. The mixture is then vigorously agitated for 1 to 3 minutes, depending on the types of sludge or solids. The agitation time is also determined in a pilot test to be performed in each case. 
     Upon completion of the dilution and decoagulation phase, the waste is transferred to the ozone treatment vessel. The ozone is added to the waste for a period to be determined in a pilot test and may range from 1 to 4 hours retention time. When the ozone treatment is completed, the waste is discharged from the ozone treatment vessel and the sludge or solids are separated for deposit. The water can be stored in a separate holding tank for reuse as dilution water in the following dilution and decoagulation processes thereby reducing the requirement of fresh water. 
     The number of required dilution and decoagulation vessels and ozone treatment vessels depends on the sludge or solids volume and retention time required for treatment, which is determined in pilot tests. 
    
    
     
       
         FIG. 1 
           
             1 . Dilution and decoagulation vessel 
             3 . Sludge or solids intake line 
             4 . Sludge or solids inlet valve 
             6 . Dilution water intake line 
             7 . Dilution water inlet valve 
             8 . Agitator motor 
             9 . Agitator shaft 
             10 . Impeller 
             11 . Decoagulant agent feeder 
             12 . Drain Valve 
             13 . Transfer Pump 
             14 . Transfer line 
             15 . Ozone reactor 
             16 . Inlet valve 
             18 . Ozone injection line 
             19 . Ozone diffuser or diffusers 
             20 . Ozone return line 
             25 . Drain valve 
         
      
       
         FIG. 2 
           
             1 . Dilution and decoagulation vessel 
             2 . Sludge or solids fill pump 
             3 . Sludge or solids intake line 
             4 . Sludge or solids inlet valve 
             5 . Dilution water fill pump 
             6 . Dilution water intake line 
             7 . Dilution water inlet valve 
             8 . Agitator motor 
             9 . Agitator shaft 
             10 . Impeller 
             11 . Decoagulant agent feeder 
             12 . Drain valve 
             13 . Transfer pump 
             14 . Transfer line 
         
      
       
         FIG. 3 
           
             13 . Transfer pump 
             14 . Transfer line 
             15 . Ozone reactor 
             16 . Inlet valve 
             17 . Ozone generator 
             18 . Ozone injection line 
             19 . Ozone diffuser or diffusers 
             20 . Ozone return line 
             21 . Ozone backflow line 
             22 . Ozone backflow preventer and check valve 
             23 . Ozone pump 
             24 . Ozone return line to ozone generator 
             25 . Drain valve 
         
      
       
         FIG. 4 
           
             15 . Ozone reactor 
             16 . Inlet valve 
             18 . Ozone injection line 
             19 . Ozone diffuser or diffusers 
             20 . Ozone return line 
         
      
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The sludge or solids are pumped by sludge or solids fill pump  2  through sludge or solids intake line  3  into dilution and decoagulation vessel  1 . The dilution water is added by the dilution water fill pump  5  through dilution water intake line  6  into dilution and decoagulation vessel  1 . A decoagulation agent is then entered into the dilution and decoagulation vessel  1  from decoagulation agent feeder  11 . The diluted waste is then vigorously agitated for a predetermined period of time, which is 1 to 3 minutes, by agitator motor  8 , agitator shaft  9  and impeller  10 . Depending on the size of solids, a grinder pump (not illustrated) may be employed upstream of sludge or solids fill pump  2 . A second impeller, 3′ or 4′ above the bottom impeller  10  may be installed. 
     Upon completion of the dilution and decoagulation phase the diluted waste is drained through drain valve  12  and transferred by transfer pump  13  through transfer line  14  and valve  16  into the ozone treatment vessel  15 . The retention time, during which ozone is constantly injected, is 1 to 4 hours. The length of the retention and ozone treatment phase is predetermined in pilot tests. 
     The ozone is generated by ozone generator  17  and flows through ozone injection line  18 , which may also be on side as illustrated in  FIG. 4 , through ozone diffuser or diffusers  19  into the waste. The ozone then flows through the waste. As the ozone bubbles rise to the top and above the waste, the ozone flows through ozone return line  20  to ozone pump  25  and is pumped through ozone return line  24  to ozone generator  17 . Ozone pump  23  also provides the pressure to ozone generator  17  to force the ozone through ozone injection line  18  and diffuser  19  to ozone reactor  15 . Ozone backflow line  21  and ozone backflow preventer and check valve  22  allow the regulation of the ozone injection into ozone treatment vessel  15 . The excess of ozone is returned through ozone return line  20  to ozone pump  23  and returned through line  24  to the ozone generator  17 . The process eliminates escape of ozone into the atmosphere by returning used ozone to ozone generator  17 , thereby creating a closed loop. The treated waste is discharged through valve  25 . 
     The discharged waste can be filtered and separated. It is desirable to transfer the separated water to a holding vessel to be used in following cycles for dilution water, thus keeping the required fresh water to a minimum. The separated sludge or solids can be deposited on landfills or used as fertilizer. 
     The system can be designed in different vessel sizes or multiple dilution and decoagulation vessels  1  and ozone treatment vessel  15  to accommodate any volume of sludge or solids. 
     Not being bound by theory, it is to be understood that not all components may be required, and that the system and process of the present invention may be applicable to the treatment of other infected sludge or solids, not only those generated by sewage. 
     
       
         
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Parameter 
                 Treatment time 
                 Concentration MPN/10 g 
               
               
                   
                   
               
             
             
               
                   
                 Fecal Coliform 
                 untreated 
                 &gt;16000 
               
               
                   
                 Total Coliform 
                 untreated 
                 &gt;16000 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Parameter 
                 Treatment time (hours) 
                 Concentration MPN/10 g 
               
               
                   
               
             
             
               
                 Total Coliform 
                 2 
                 27 
               
               
                   
               
             
          
         
       
     
     
       
         
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                 Parameter 
                 Treatment time (hours) 
                 Concentration MPN/10 g 
               
               
                   
               
             
             
               
                 Total Coliform 
                 3 
                 2