EP2523910A1 - Method and system of sludge treatment - Google Patents
Method and system of sludge treatmentInfo
- Publication number
- EP2523910A1 EP2523910A1 EP10802021A EP10802021A EP2523910A1 EP 2523910 A1 EP2523910 A1 EP 2523910A1 EP 10802021 A EP10802021 A EP 10802021A EP 10802021 A EP10802021 A EP 10802021A EP 2523910 A1 EP2523910 A1 EP 2523910A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sludge
- electric field
- volume
- dewatering
- reactor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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
- C02F11/15—Treatment of sludge; Devices therefor by de-watering, drying or thickening by treatment with electric, magnetic or electromagnetic fields; by treatment with ultrasonic waves
-
- 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
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
-
- 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
- C02F1/48—Treatment of water, waste water, or sewage with magnetic or electric fields
-
- 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
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/127—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering by centrifugation
-
- 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
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/4612—Controlling or monitoring
- C02F2201/46125—Electrical variables
- C02F2201/46135—Voltage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/4612—Controlling or monitoring
- C02F2201/4615—Time
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/46155—Heating or cooling
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/4616—Power supply
- C02F2201/4617—DC only
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/02—Temperature
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/06—Controlling or monitoring parameters in water treatment pH
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/42—Liquid level
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/44—Time
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/04—Flow arrangements
- C02F2301/043—Treatment of partial or bypass streams
-
- 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
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Definitions
- This invention relates to a method of treating sludges and has been designed particularly though not necessarily solely for use in the treatment of biosolids.
- the treatment of sewage sludge results in a final residue for disposal.
- This residue is often referred to as biosolids.
- the dry solids (DS) contents of the biosolids varies typically from 0.5% DS to 4% DS.
- the production of this dilute phase sludge from treated waste water depends on the type of treatment process used.
- the dilute phase is discharged from a process comprising of mesophilic digesters, thermophilic digesters, extended aeration, activated sludge, waste activated sludge, primary treatment, sequencing batch reactors and in certain processes combinations of the above.
- the dilute phase is dewatered by applying pressure in belt presses, other type of presses, or decanter centrifuges.
- the dewatered cake typically has a concentration of 13% DS to 30% DS and is further treated by thermal drying, lime stabilisation, composting, solar drying or by use in land fill.
- the cost of the final disposal depends on the DS content of the sludge. The higher the DS the lower the cost.
- An aspect of the present invention is to provide a method of treating sludges which will obviate or minimize the foregoing disadvantages in a simple yet effective manner.
- a method of treating sludge includes applying an electric field to at least a portion of the volume of the sludge prior to further dewatering of the sludge.
- the sludge comprises dilute phase sludge.
- the electric field is a DC electric field.
- the pH of the sludge is adjusted to substantially between 5 and 6.
- the pH may be adjusted by addition of an acid, such as, for example, sulphuric acid or hydrochloric acid.
- the electric field is applied through carbon, or graphite, or carbon fibre, or stainless steel electrodes or plates.
- the plates may be positioned in a holding vessel of a reactor.
- the voltage of the DC field applied to the sludge is between substantially 2 volts and substantially 20 volts. In one of the embodiments the voltage of the DC field applied to the sludge is between substantially 2 volts and substantially 14 volts. In one of the embodiments the voltage applied to the sludge is between substantially 3 volts and substantially 5 volts.
- the current density of the DC field applied to the sludge is between substantially 10 amps per square meter to substantially 80 amps per square meter. In one of the embodiments the current density is from substantially 20 amps per square meter to substantially 40 amps per square meter. In one of the embodiments the current density is substantially 22 amps per square meter.
- the application time of the DC field to the sludge is from substantially 2 minutes to substantially 10 minutes. In one of the embodiments the application time is substantially 5 minutes.
- the temperature of at least a portion of the volume of the sludge is adjusted to substantially from 15 0 C to 37 0 C. In one of the embodiments the temperature is substantially from 25 0 C and 37 0 C.
- the method further comprises adding polymer at a dose rate of substantially 4kg per dry ton to substantially 20kg per dry ton after the application of the electric field to the sludge. In one of the embodiments the method further includes pressing or centrifuging the sludge after the polymer has been added.
- a sludge dewatering system in another general aspect, includes a reactor to apply an electric field across at least a portion of the volume of the sludge and a dewatering station to dewater the sludge.
- Embodiments may include one or more of the following or above features.
- a mixer may be positioned between the reactor and the dewatering station wherein the mixer adds a polymer to the sludge.
- a sludge tank may be used to contain at least a portion of the volume of the sludge and to receive an acid to adjust the pH of the sludge.
- An inlet pipe may deliver at least a portion of the volume of the sludge to the sludge tank and a bypass line may connect the inlet pipe to the mixer to bypass the sludge tank and the reactor with a portion of the volume of the sludge.
- a bypass line connects the sludge tank to the mixer to bypass the reactor with a portion of the volume of the sludge.
- the dewatering system of claim may include a heating system to raise the temperature of the sludge.
- the reactor includes a holding vessel and a series of positive and negative plates in the holding vessel to apply the electric field.
- An inlet may feed sludge to the interior of the holding vessel, through a collection chamber and to an outlet that removes the sludge from the holding vessel after the electric field is applied.
- Figure 1 is a diagrammatic representation of equipment of the sludge dewatering system
- Figure 2 is a perspective view and enlargement of an electric reaction tank for use in sludge dewatering
- Figure 3 shows how banks of electrodes can be built up for alternative reaction tanks usable.
- Figures 4 - 6 are various diagrammatic representations of the sludge dewatering system with bypass lines.
- dilute phase sludge typically 0.5 to 4% more particularly 2 to 3% dry solids is provided at 1 and mixed with acid provided from an acid pump 2.
- the acid is sulphuric acid or hydrochloric acid.
- the sludge and acid is mixed in a mixer 3 and when thoroughly mixed is taken through outlet pipe 4 to reactor 5.
- a typical flow rate of the dilute phase sludge is from about 10 to about 100 m3/h.
- the reactor 5 applies a DC field across the sludge.
- the reactor 5 may comprise a holding vessel 6 with an inlet 7 towards to the bottom of the vessel 6.
- the vessel has therein a series of plates 8 across which the DC field is applied.
- the gap between the plates is preferably from about 10mm to about 30mm. We have found about a gap of 15mm gives good results.
- inlet 7 feeds to the interior of holding vessel 6 in which plates 8 are positioned.
- Positive and negative plates are connected by electrically conducting bridges 20 and 21 connecting all positive or all negative plates 8. After passing upwardly past plates 8 the mixture passes downwardly at 22 to collection chamber 11 to outlet 23.
- Figure 3 shows how, banks of plates 8 can be built up to provide a range of sizes of holding vessel 6, 6a, 6b, 6c, 6d.
- Figure 3 shows the banks of plates in pairs, each pair having an inlet 7 and the chamber 11 being positional between each bank of plates 8 in the pair.
- the DC field is desirably between 2 and 20 volts, preferably 2 and 14 volts, and most preferably between substantially 3 volts and substantially 5 volts.
- the current density is typically between 10 to 80 amps per square meter, preferably 20 to 40 amps per square meter. About 22 amps per square meter has been found to give good results.
- the current to achieve this current density will depend on the size of the plant being for example 60 to 400 amps preferably 100 to 200 amps.
- the temperature in the reactor is adjusted to desirably be between substantially 15 0 C and 370C and more particularly substantially 250C to substantially 37 0 C. Any desirable heating method can be used.
- the sludge moves upwardly through the vessel 6 substantially in the direction of arrow 10 so as to collect in a collection chamber 11 after exiting the top of the reactor container 6.
- the sludge flows upwardly through a series of space provided between in the electrodes.
- the speed of flow through the reactor 5 is adjusted so that the application-time of the-field-to the sludge is between substantially 2 to substantially 10 minutes and most preferably substantially 5 minutes.
- the sludge After exiting the chamber 11 to outlet 12 the sludge is mixed with a polymer typically a cationic coagulation agent in a mixer 13 from where the sludge travels to a further dewatering stage at 14 which may be of known form, for example, belt presses, centrifuges or the like.
- the final dry solids could be 25% DS to 40% DS.
- the invention provides a method of assisting the dewatering of sludges in which savings can be achieved. Savings can be achieved in the amount of polymer used and also in the reduction of electricity consumption. It is also believed that time in the dryer could be reduced by substantially 50% which again effects a reduction in electricity consumption.
- the application of a DC electric field is carried out when the fluid has low dry solids. At these low dry solids the application of electricity is easily carried out in a safe manner.
- existing polymer dosing and dewatering equipment in the wastewater treatment plant can be used as the method of the present invention provides a stand alone separate element which can be incorporated into the existing wastewater treatment plant.
- the two step process is an effective method to reduce polymer use by up to 20% to 50%.
- a bypass line 20 may be used to route some of the sludge by the reactor 5 and/or other components.
- the bypass line 20 bypasses the sludge tank 3 and the reactor 5.
- the amount of sludge passing through the bypass line may be between 10% and 90%, and more particularly, between 20% to 50% of the sludge by volume.
- the proportion may be controlled by a suitable valve 21, such as a directional control valve or other suitable valve, or by pipe diameter or in any other suitable manner.
- the sludge After exiting the chamber 11 to outlet 12 the sludge is mixed with the sludge from the bypass line 20 and with the polymer as explained above and the sludge travels to the further dewatering stage 14.
- bypass line 20 bypasses only the reactor 5 and not the sludge tank/mixer 3.
- Figure 6 shows a construction similar to Figure 5 in which the electrodes of the reactor are substantially horizontal.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Treatment Of Sludge (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NZ57851209 | 2009-07-20 | ||
PCT/IB2010/053314 WO2011010285A1 (en) | 2009-07-20 | 2010-07-20 | Method and system of sludge treatment |
Publications (2)
Publication Number | Publication Date |
---|---|
EP2523910A1 true EP2523910A1 (en) | 2012-11-21 |
EP2523910A4 EP2523910A4 (en) | 2014-07-23 |
Family
ID=43498822
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP10802021.5A Withdrawn EP2523910A4 (en) | 2009-07-20 | 2010-07-20 | Method and system of sludge treatment |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2523910A4 (en) |
WO (1) | WO2011010285A1 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009017426A1 (en) * | 2007-07-30 | 2009-02-05 | Fde Process Systems Limited | Improvements in/or relating to a method of treating sludges |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6395176B1 (en) * | 1995-11-02 | 2002-05-28 | D-H2O L.L.C. | Method for treating waste-activated sludge using electroporation |
US5928493A (en) * | 1997-11-24 | 1999-07-27 | Kaspar Electroplating Corporation | Process and apparatus for electrocoagulative treatment of industrial waste water |
SG131809A1 (en) * | 2005-10-28 | 2007-05-28 | Lee Thiam Seng | Advanced electro-coagulation device and process of using the same for wastewater treatment |
US7563939B2 (en) * | 2005-12-14 | 2009-07-21 | Mark Slater Denton | Method for treating radioactive waste water |
-
2010
- 2010-07-20 EP EP10802021.5A patent/EP2523910A4/en not_active Withdrawn
- 2010-07-20 WO PCT/IB2010/053314 patent/WO2011010285A1/en active Application Filing
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009017426A1 (en) * | 2007-07-30 | 2009-02-05 | Fde Process Systems Limited | Improvements in/or relating to a method of treating sludges |
Non-Patent Citations (1)
Title |
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See also references of WO2011010285A1 * |
Also Published As
Publication number | Publication date |
---|---|
EP2523910A4 (en) | 2014-07-23 |
WO2011010285A1 (en) | 2011-01-27 |
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Legal Events
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RIC1 | Information provided on ipc code assigned before grant |
Ipc: C02F 11/12 20060101ALI20140619BHEP Ipc: C02F 9/06 20060101ALI20140619BHEP Ipc: C02F 1/46 20060101AFI20140619BHEP Ipc: B01D 21/00 20060101ALI20140619BHEP Ipc: C02F 1/66 20060101ALI20140619BHEP Ipc: C02F 1/48 20060101ALI20140619BHEP |
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STAA | Information on the status of an ep patent application or granted ep patent |
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18D | Application deemed to be withdrawn |
Effective date: 20150122 |