METHOD FOR MAKING BROWN GREASE

1 . A method for recovering grease from wastewater, the method comprising:

receiving wastewater comprising an aqueous phase and an organic phase, wherein the organic phase comprises solids and grease;

pretreating the wastewater to produce a waste sludge stream comprising water, solids, and grease, wherein a substantial amount of the solids and grease from the wastewater are extracted into the waste sludge stream;

separating the waste sludge in a first separation stage to provide a first separation phase consisting essentially of solids, and a second separation phase comprising an immiscible liquid mixture of grease and water; and

separating the second separation phase to provide a third separation phase consisting essentially of water and a fourth separation phase consisting essentially of grease.

2 . The method of claim 1 , wherein the wastewater is from an animal processing plant.

3 . The method of claim 2 , wherein the wastewater originates from one or more waste streams from inside the animal processing plant.

4 . The method of claim 1 , wherein the organic phase of the wastewater stream comprises sand, grit, animal by-products, animal waste, blood, fine bone, tissue, muscle, hair, nails, or a combination or mixture thereof.

5 . The method of claim 1 , whereby pretreating the wastewater comprises a dissolved air flotation system.

6 . The method of claim 5 , whereby pretreating is conducted at an operating temperature of about 90° F.

7 . The method of claim 1 , wherein the waste sludge stream comprises from about 60%-90% water, from about 5%-30% grease, and about 5%-30% solids.

8 . The method of claim 1 , further comprising the step of heating the waste sludge stream to a temperature of about 150-220° F.

9 . The method of claim 1 , further comprising the step of heating the second separation phase to a temperature of about 200-250° F.

10 . The method of claim 1 , further comprising the step of coagulating the grease in the immiscible liquid mixture.

11 . A system for recovering grease from wastewater, the system comprising:

a pretreatment facility capable of extracting a substantial portion of the solids from the wastewater stream to produce a waste sludge;

a first separator capable of separating the waste sludge into a first separation phase consisting essentially of solids from the waste sludge, and a second separation phase comprising an immiscible mixture of water and grease;

a second separator capable of separating the second separation phase into a third separation phase consisting essentially of water, and a fourth separation phase consisting essentially of grease.

12 . The system of claim 11 , wherein the wastewater is from an animal processing plant.

13 . The apparatus of claim 11 , wherein the pretreatment facility is a dissolved air flotation system.

14 . The apparatus of claim 11 , whereby the pretreatment system comprises a heater for maintaining the temperature of the wastewater at about 90° F.

15 . The system of claim 11 , further comprising a holding tank downstream of the pretreatment apparatus.

16 . The system of claim 11 , further comprising a sparge tank downstream of the holding tank, wherein said sparge tank is capable of heating the waste sludge to a temperature of about 150-220° F.

17 . The system of claim 11 , wherein the first separator means is a two-phase solid/liquid decanter centrifuge.

18 . The system of claim 11 , further comprising a heat exchanger downstream of the first separator that heats the immiscible mixture of water and grease to a temperature of about 200-250° F.

19 . The system of claim 11 , further comprising an in-line flocculator to coagulate the grease in the immiscible mixture of water and grease.

20 . The system of claim 11 , wherein the second separator is a two-phase liquid/liquid separator.