Method and system for the production of biofertilisers

• US 8,124,401 B2
• Filed: 06/02/2006
• Issued: 02/28/2012
• Est. Priority Date: 06/02/2005
• Status: Active Grant

• Current Assignee: Institut De Recherche Et De Developpement En Agroenvironnement Inc. (IRDA)
• Original Assignee: Institut De Recherche Et De Developpement En Agroenvironnement Inc. (IRDA)
• Inventors: Dutil, Camil, Zegan, Dan, Douhéret, Jocelyn, Chabot, Rock
• Primary Examiner(s): LANGEL, WAYNE A
• Application Number:
  US11/916,124
• Publication Number:
  US 20090301150A1
• Time in Patent Office: 2,097 Days
• Field of Search: 71/8, 71/9, 71/10, 435/290.2, 435/262.5
• US Class Current: 435/262.5
• CPC Class Codes: C02F 11/16 using drying or composting beds
• CPC Class Codes: C05F 17/40 Treatment of liquids or slurries
• CPC Class Codes: C05F 17/60 Heating or cooling during the treatment
• CPC Class Codes: C05F 3/00 Fertilisers from human or animal excrements, e.g. manure
• CPC Class Codes: C05F 3/06 Apparatus for the manufacture
• CPC Class Codes: C05F 7/00 Fertilisers from waste water, sewage sludge, sea slime, ooze or similar masses
• CPC Class Codes: Y02A 40/20 Fertilizers of biological origin, e.g. guano or fertilizers made from animal corpses
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
• CPC Class Codes: Y02P 20/133 Renewable energy sources, e.g. sunlight
• CPC Class Codes: Y02P 20/145 the feedstock being materials of biological origin
• CPC Class Codes: Y02W 10/30 Wastewater or sewage treatment systems using renewable energies
• CPC Class Codes: Y02W 10/37 using solar energy
• CPC Class Codes: Y02W 30/40 Bio-organic fraction processing; Production of fertilisers from the organic fraction of waste or refuse

Abstract

The invention relates to a method and a system for producing biofertilizers, from sludge that are stabilized, dried, and rich in fertilizing matters originating from high load effluent treatment method. Such solution may be integrated into an already existing treatment facility for industrial, municipal, or agronomical organic effluents (100), and is based on recovering the thermal energy created during the treatment steps of such system in bioreactors (120), air suppression units (122), biodrying units (500), drying units (600), and other units. Such recovery of energy creates a synergy that allows the increase of efficacy and yield of bioreactors (120) due to a greater stability from the temperature regulation, thus ensuring an important energy saving for the final drying step in producing biofertilizers.

Claims

1. A method for drying a sludge mixture containing organic waste comprising the steps of:

a) obtaining a sludge mixture having a percentage of dry matter between 10 and 40%;

b) drying said sludge mixture by exothermic biodrying at a temperature between 50 and 75°

C., for 3 to 20 days to obtain dehumidified organic matter that has reduced pathogenic microorganism population and having less odor;

c) recovering thermal energy released from step b) to direct it towards a drying unit; and

d) further drying the organic matter of step b) in said drying unit by applying the thermal energy recovered in step c) until obtaining a dried organic matter that is disinfected, odorless and with a moisture content of less than 30%.

2. The method of claim 1, wherein the sludge mixture includes a dehumidified organic matter obtained in step b) and dried organic matter obtained from step d).

3. The method of claim 1, wherein said biodrying in step b) is carried out between 3 to 9 days.

4. The method of claim 1, wherein said biodrying in step b) is carried out at a temperature between 60°

C. to 70°

C.