Methods for treatment of waste streams
First Claim
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1. A method of treating a waste stream, comprising the steps of:
- subjecting a waste stream to a secondary, biological treatment step in which organic components in the waste stream are transformed into biomass;
then fractionating the biomass by mechanical shearing by a force that produces a substantial proportion of particles of about 2 microns or less such that the microbial cells in the biomass are sheared allowing nutrients to be released from the cells; and
recirculating the nutrients released by the fractionating of the biomass to be used in the biological treatment step.
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Abstract
A method for treating wastewater is useful in treatment of biomass (sludge) resulting from wastewater treatment, particularly for biological sludges of aerobic, facultative and/or anaerobic origin. The invention relates fractionation of microorganisms and organic materials within the sludge by mechanical shearing, in combination with heat, chemical and/or biochemical treatment to improve waste treatment and to release nutrients for recirculation for use by microorganisms in the waste treatment system.
164 Citations
20 Claims
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1. A method of treating a waste stream, comprising the steps of:
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subjecting a waste stream to a secondary, biological treatment step in which organic components in the waste stream are transformed into biomass;
then fractionating the biomass by mechanical shearing by a force that produces a substantial proportion of particles of about 2 microns or less such that the microbial cells in the biomass are sheared allowing nutrients to be released from the cells; andrecirculating the nutrients released by the fractionating of the biomass to be used in the biological treatment step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of treating a waste stream, comprising the steps of:
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collecting sludge from the waste stream after a biological treatment step; fractionating the sludge by mechanically shearing the sludge by a force that produces a substantial proportion of particles of about 2 microns or less to disrupt microorganisms within the sludge so that nutrients are released from within the microorganisms; and recirculating the nutrients released by fractionating the sludge to the biological treatment step. - View Dependent Claims (16)
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17. A method for treating sludge from a municipal waste system, comprising the steps of:
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(a) receiving a blend of sludge produced by an anaerobic digester acting on primary and waste secondary sludges, said digester comprising microbial cells; (b) mechanically shearing the sludge blend by a force that produces a substantial proportion of particles of about 2 microns or less, so that microbial cells within the sludge are disrupted to the extent that nutrients within the cells are released and recirculated for use in the sludge treating method; and (c) returning the sheared sludge blend to the anaerobic digester.
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18. A closed loop system of sludge recirculation, comprising the steps of
a. subjecting a waste stream to a secondary, biological treatment step in which organic components in the waste stream are transformed into biomass; -
b. pretreating the biomass with at least one of the group consisting of chemicals, heat and biochemicals; c. fractionating the biomass by mechanical shearing using a force that produces a substantial proportion of particles of about 2 microns or less such that the microbial cells in the biomass are sheared allowing nutrients to be released from the cells; and d. recirculating the nutrients released by the fractionating of the biomass to be used in the biological treatment step a, thereby forming a closed loop. - View Dependent Claims (19, 20)
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Specification