Two phase anaerobic digestion process utilizing thermophilic, fixed growth bacteria

A method of anaerobic treatment of waste water comprising the steps of:

• a. introducing waste water containing organic material into a first reactor vessel containing thermophilic, fixed growth, acidogenic bacteria;
• b. fermenting the waste water in said first reactor vessel under anaerobic conditions at a pH in a range between about 5 and 6 and a temperature in a range between about 115 to 160 degrees Fahrenheit to produce a first effluent;
• c. conveying the first acid effluent to a second reactor vessel containing thermophilic, fixed growth, acidogenic bacteria;
• d. thereafter fermenting the first effluent in said second reactor vessel under anaerobic conditions at a pH in a range between about 5 and 6 and a temperature in a range between about 115 to 160 degrees Fahrenheit to produce a second effluent;
• e. conveying the second effluent to a third reactor vessel containing thermophilic, fixed growth, methanogenic bacteria;
• f. fermenting the second effluent in said third reactor vessel under anaerobic conditions at a pH in a range between about 7.2 and 8.2 and a temperature in a range between about 115 to 160 degrees Fahrenheit to produce a third effluent and gas including methane;
• g. collecting at least a portion of the gas including methane produced through the fermentation of the second effluent in the third reactor vessel;
• h. conveying the third effluent to a fourth reactor vessel containing thermophilic, fixed growth, methanogenic bacteria;
• i. fermenting the third effluent in said fourth reactor vessel under anaerobic conditions at a pH in a range between about 7.2 and 8.2 and at a temperature in a range between about 115 to 160 degrees Fahrenheit to produce a fourth effluent and gas including methane;
• j. collecting at least a portion of the gas including methane produced through the fermentation of the third effluent in said fourth reactor vessel;
• and
• k. removing the fourth effluent.