Pretreatment of high solid microbial sludges
First Claim
1. A process for pretreating microbial sludge in order to disrupt cellular integrity of the sludge and enhance secondary anaerobic digestion, comprising:
- a) pressurizing and pumping the sludge to be pretreated to a pretreatment reactor;
b) providing steam to the pretreatment reactor;
c) mixing the steam and sludge in the pretreatment reactor to heat the sludge;
d) flashing the sludge to decrease the pressure;
e) applying shear forces to the sludge wherein the cellular integrity of the sludge is disrupted.
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Abstract
A process and apparatus for pretreating microbial sludges in order to enhance secondary anaerobic digestion. The pretreatment process involves disrupting the cellular integrity of municipal sewage sludge through a combination of thermal, explosive decompression and shear forces. The sludge is pressurized and pumped to a pretreatment reactor where it is mixed with steam to heat and soften the sludge. The pressure of the sludge is suddenly reduced and explosive decompression forces are imparted which partially disrupt the cellular integrity of the sludge. Shear forces are then applied to the sludge to further disrupt the cellular integrity of the sludge. Disrupting cellular integrity releases both soluble and insoluble organic constituents and thereby renders municipal sewage sludge more amenable to secondary anaerobic digestion.
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Citations
18 Claims
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1. A process for pretreating microbial sludge in order to disrupt cellular integrity of the sludge and enhance secondary anaerobic digestion, comprising:
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a) pressurizing and pumping the sludge to be pretreated to a pretreatment reactor; b) providing steam to the pretreatment reactor; c) mixing the steam and sludge in the pretreatment reactor to heat the sludge; d) flashing the sludge to decrease the pressure; e) applying shear forces to the sludge wherein the cellular integrity of the sludge is disrupted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A process for treating microbial sludge, comprising:
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a) pressurizing and pumping sludge to a pretreatment reactor; b) providing steam to the pretreatment reactor; c) mixing the steam and sludge in the pretreatment reactor to heat and soften the sludge; d) flashing the mixed sludge to lower pressure; e) applying shear forces to the flashed sludge; f) treating the sludge after the application of shear forces to secondary anaerobic digestion. - View Dependent Claims (18)
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Specification