US 9,868,079 B2Granted

Method and system for filtration and filtration cake layer formation

AssigneeGrudfos Holding A/S

InventorsDominik Marek Dominiak, Tom Bjerregaard Jæger

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Abstract

The present invention relates to filtration of liquids, such as water, containing substances that desirably should be removed from the liquids. The invention relates in particular to a filtration cake, being produced in situ of a cleaning system from substances that desirably should be filtered away. Particular preferred embodiments of the present invention relate to treatment of waste water, where an activated sludge is provided, which sludge contains activated sludge flocs. These flocs are accumulated on a fluid penetrable support structure to form a layer of flocs, which subsequently is compressed to form a filter of desired properties. The invention also relates to adapting waste water—or other liquids containing biodegradable substances—to optimized biodegradation and filtration by deflocculating flocs in an activated sludge during or before a biodegradation step and subsequently promoting re-flocculation prior to filtering or other means of biomass separation.

Claims11

Dependent claims

A method for providing a filtration cake of a filter element for filtering an activated sludge supernatant through the filtration cake comprising:

an accumulation phase (A) comprising accumulating activated sludge flocs on a support structure by inducing a pressure difference to generate a flow of sludge, towards and through the support structure until a desired layer of flocs has been established on the support structure, wherein the pressure difference during the accumulation phase (A) is constant over time or increased over time and the fluid flowing through the support structure is recirculated during the accumulation phase (A), and
a compression phase (B) comprising increasing the pressure difference to a level being sufficient to compress the layer of accumulated flocs on the support structure into a filtration cake of desired properties, wherein the compression phase is performed subsequent to the accumulation phase,
wherein the filtration cake is provided solely by flocs present in the activated sludge, and the pressure increase initiating the compression phase (B) is a step-wise increase.

Dependencies are inferred from the claim text.

Facts

Application: 14/009,627Filed 27 Mar 2012
Priority: DK 2011 701605 Apr 2011
Published: US 2014/0061126 A16 Mar 2014
Granted: 16 Jan 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

B01D 29/00
Filters with filtering elements stationary during filtration
B01D 29/03
With flat filtering elements: self-supporting
B01D 29/62
Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00;…:…
B01D 29/64
Regenerating the filter material in the filter: by scrapers, brushes, nozzles, or the like, acting on the cake side of the filtering element