Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
  • C02F11/147—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using organic substances
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
  • B01D65/02—Membrane cleaning or sterilisation ; Membrane regeneration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D65/00—Accessories or auxiliary operations, in general, for separation processes or apparatus using semi-permeable membranes
  • B01D65/08—Prevention of membrane fouling or of concentration polarisation
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
  • C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
  • C02F3/1236—Particular type of activated sludge installations
  • C02F3/1268—Membrane bioreactor systems
  • C02F3/1273—Submerged membrane bioreactors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the present invention relates to the treatment of waste water using membrane bio-reactors.
• the daily flow rate at the top that is to say liquid effluent from the dehydration operation, represents commonly 1 to 5% of the daily wastewater supply rate urban and sometimes more than 10% of the daily flow when it comes to treating industrial wastewater.
• This option can manage the risk of clogging of the membranes of the bio-reactor, but it does not eliminate the risk of an accidental overdose of polyelectrolytes during the treatment of sludge. Controlling such a risk is all the more difficult to ensure since the quantitative analysis of the residuals of the polyelectrolytes contained in the head returns is today technically complex, even impossible. b) By subjecting the effluents from the sludge dewatering treatment to a pre-treatment in order to destroy the residual quantities of polyelectrolytes.
• the present invention has therefore set itself the objective of allowing the recycling, at the head of the water sector of a wastewater treatment installation by membrane bio-reactors, of the effluent originating from the sludge sector, ie that is to say the step of dewatering excess sludge from the water industry, completely eliminating the risk of clogging of the membranes of the water industry by residual polyelectrolytes from the mud industry.
• this invention relates to a process for treating waste water by a membrane bio-reactor comprising a step of dewatering the sludge and recycling, at the top of the bio-reactor, of the liquid effluent from the sludge dewatering, characterized in that:
• the biological sludges extracted from the bio-reactor are brought into contact with the liquid effluent originating from the sludge dehydration step so that the residual content of said effluent in polyelectrolyte having been used for conditioning the sludges during the dewatering step migrates to biological sludge; the biological sludge is separated from the liquid effluent so as to obtain, on the one hand a liquid effluent free of polyelectrolyte and on the other hand a biological sludge loaded with polyelectrolyte; the liquid effluent free of polyelectrolyte is recycled at the top of the membrane bio-reactor and, - the biological sludge loaded with polyelectrolyte is discharged towards the dehydration stage.
• the separation of the biological sludge from the liquid effluent is carried out by filtration on icrofiltration or ultrafiltration membranes.
• the membranes of the sludge system act as a real physical barrier and produce an effluent free of traces of polyelectrolytes which can be recycled on the system. water, that is to say at the head of the bio-reactor, without risk of clogging of the membranes of the latter, the biological sludge or flocs, loaded with polyelectrolytes being discharged towards the sludge dehydration stage.
• FIG. 1 is a schematic view showing an installation implementing the method according to the present invention and, Figure 2 is a view similar to Figure 1, relating to an example of implementation of the method of the invention.
• FIG 1 there is shown schematically in 1 the water treatment of urban or industrial waste water, this sector comprising a membrane bio-reactor.
• This installation includes a workshop for dewatering sludge from the water industry, generally designated by the reference 4, with an injection of polyelectrolyte for the conditioning of sludge, this workshop producing, on the one hand dehydrated sludge and, on the other hand, a dewatering effluent evacuated using a pipe 6.
• the excess sludge from the water system is brought into contact with the dewatering effluent brought through the pipe 6, in a contactor 2.
• the residual quantity of polyelectrolyte contained in the dehydration effluent migrates from the liquid phase towards the biological flocs or sludges coming from the water sector, by phenomena of adsorption, absorption and flocculation at levels very far from saturation.
• the polyelectrolyte fixing yield is close to 100%.
• the contactor 2 can for example be a fast-mixing reactor "TURBACTOR” as described in the Water Technical Memento, Volume 2, page 638, edited by DEGREMONT (Edition du Cinquantenaire 1989).
• the separation of the biological mud and the liquid phase is then carried out by filtration so as to obtain a liquid effluent free of polyelectrolyte, recycled at the head of the water sector using a pipe 7 and a biological mud loaded with polyelectrolyte which is brought to the dehydration workshop 4 via line 5.
• this separation can be carried out by filtration on icrofiltration or ultrafiltration membranes acting as a physical barrier so as to produce an effluent free of traces of polyelectrolyte.
• This effluent can therefore be recycled on the water sector without risk of clogging of the membranes of this sector.
• the membranes of the mud sector can have any geometry (flat, tubular, hollow fiber), be made of any suitable material (organic or ceramic) and have any operating configuration (external system or submerged system).
• Figure 2 illustrates an example of implementation of the method of the invention.
• the characteristic values of the installation have been mentioned used during this implementation and the data obtained.
• the area of membranes 3 (60 m 2 ) installed on the sludge sector represents only 3% of the area of membranes (2000 m 2 ) of the water sector bio-reactor.
• the risk of accidentally clogging the membranes is limited to 3% of the total membrane surface of the treatment installation.
• the fact of dissociating the membranes of the water industry 1 and the membranes 3 of the mud industry enables chemical washing of the membranes of the mud industry without reducing the filtration capacity of the water industry.
• the dehydration effluent recycled at the top of the water sector is free of polyelectrolyte, which eliminates any risk of clogging of the membranes of the water sector.
• the invention makes it possible to reduce the consumption of polyelectrolyte used during the conditioning of the sludge in the workshop. dehydration 4.
• the dosage of polyelectrolyte necessary for the dewatering of the sludge produced by the water sector is 10 kg / TMeS. Recycling polyelectrolyte “leaks” to the dehydration workshop (line 5) makes it possible to reduce polyelectrolyte consumption by 10%, the latter then being 1.8 kg / d instead of 2 kg / d.
• the advantages brought by the present invention are in particular the following: - it makes it possible to control the clogging character of the liquid effluents resulting from the sludge dehydration stage by transfer of a small quantity of polyelectrolyte to a large quantity of biological flocs (ratio 500 to 4000); - It guarantees the absence of residual traces of polyelectrolyte in the liquid effluent recycled at the head of the water sector, which eliminates the risk of clogging of the membranes of this sector; - it makes it possible to reduce the dosage of polyelectrolyte during the dewatering of the sludge thanks to the recycling of polyelectrolyte leaks on the sludges coming from the water sector, before their conditioning.

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• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Biodiversity & Conservation Biology (AREA)
• Microbiology (AREA)
• General Chemical & Material Sciences (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Activated Sludge Processes (AREA)
• Treatment Of Sludge (AREA)

Applications Claiming Priority (3)

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• 2002
  • 2002-09-24 FR FR0211788A patent/FR2844784B1/fr not_active Expired - Fee Related
• 2003
  • 2003-09-22 TR TR200502228T patent/TR200502228T3/xx unknown
  • 2003-09-23 UA UAA200503865A patent/UA80724C2/uk unknown
  • 2003-09-23 WO PCT/FR2003/002796 patent/WO2004028986A2/fr active Application Filing
  • 2003-09-23 DE DE2003798216 patent/DE03798216T1/de active Pending
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  • 2003-09-23 BR BR0314842A patent/BR0314842A/pt active Search and Examination
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• 2005
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• 2006
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