# US 2019/0168166 A1 · Cleaning method of a water-filtration system under operation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0168166 A1 - Document ID: US20190168166A1 - Status: Published application - Kind: A1 - Application number: 16/314,571 - Filed: 2016-07-01 - Published: 2019-06-06 - Earliest claimed: 2016-07-01 - Assignees: T0Tal SA; Veolia Water Solutions & Technologies Support; Saipem S.P.A. - Applicants: Total SA; Veolia Water Solutions & Technologies Support; Saipem S.A. - Inventors: Jérôme ANFRAY; Pierre PEDENAUD; Graeme SKIVINGTON; Thomas DELAPLACE - Web page: https://patentgrep.com/patent/US20190168166A1 ## CPC - B01D 65/02: Membrane cleaning or sterilisation {; Membrane regeneration} - B01D 61/04: Feed pretreatment - B01D 61/16: Feed pretreatment - B01D 65/08: Prevention of membrane fouling or of concentration polarisation - C02F 1/441: {by reverse osmosis} - C02F 1/442: {by nanofiltration} - C02F 1/444: {by ultrafiltration or microfiltration} - B01D 2311/06: Specific process operations in the permeate stream - B01D 2311/08: Specific process operations in the concentrate stream - B01D 2311/12: Addition of chemical agents - B01D 2311/24: Quality control - B01D 2311/2512: to feed side - B01D 2311/2523: to feed side - B01D 2315/06: Submerged-type; Immersion type - B01D 2315/10: Cross-flow filtration - B01D 2321/16: Use of chemical agents - B01D 2321/162: Use of acids - B01D 2321/164: Use of bases - B01D 2321/168: Use of other chemical agents - B01D 2321/205: Integrated pumps - B01D 2321/40: Automatic control of cleaning processes - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes) ## Abstract The present invention concerns a method for cleaning a filtration system under operation. The filtration system comprising a hydraulic circuit Cp recycling the permeate stream to the feed side of the membrane and/or a hydraulic circuit Cr recycling the retentate stream to the feed side of said membrane. The method comprises injecting an amount of a chemical product into the filtration system in the hydraulic circuit Cp or in the hydraulic circuit Cr or upstream of the cross-flow filtration membrane, setting the proportion of recycled permeate stream or recycled retentate stream collected in the hydraulic circuit Cp and/or Cr to enable the recycling of a significant amount of unreacted chemical product having passed through said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane, as well as a filtration system for carrying out said method. ## Claims ### Claim 1 A method for cleaning a filtration system under operation, said filtration system comprising: a cross-flow filtration membrane having: a feed side fed with a feed stream, a permeate side wherein a permeate stream is recovered and a retentate side wherein a retentate stream is recovered, a hydraulic circuit Cp connecting the permeate side of said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane, said hydraulic circuit Cp allowing the recycling of a proportion of the permeate stream to the feed side of said cross-flow filtration membrane, and/or a hydraulic circuit Cr connecting the retentate side of said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane, said hydraulic circuit Cr allowing the recycling of a proportion of the retentate stream to the feed side of said cross-flow filtration membrane, said method comprising: injecting an amount of a chemical product into the filtration system which is under operation in the hydraulic circuit Cp or in the hydraulic circuit Cr or upstream of said cross-flow filtration membrane, setting the proportion of recycled permeate stream or recycled retentate stream collected in the hydraulic circuit Cp and Cr to enable the recycling of a significant amount of unreacted chemical product having passed through said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane. ### Claim 2 (depends on 1) The method according to claim 1, wherein the cross-flow filtration membrane is a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane. ### Claim 3 (depends on 1) The method according to claim 1, wherein the cross-flow filtration membrane is a ceramic membrane or an organic membrane. ### Claim 4 (depends on 1) The method according to claim 1, wherein the chemical product is a biocide, an acid, a base, a cleaning agent such as surfactant agent, a detergent, a complexation agent or a scale dissolver, or a mixture thereof. ### Claim 5 (depends on 1) The method according to claim 1, wherein the proportion QC permeate of recycled permeate stream collected in the hydraulic circuit Cp is at least 10%, in particular at least 20%, in particular at least 30%, in particular at least 40%, in particular at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%. ### Claim 6 (depends on 1) The method according to claim 1, wherein the proportion QC retentate of recycled retentate stream collected in the hydraulic circuit Cr is at least 10%, in particular at least 20%, in particular at least 30%, in particular at least 40%, in particular at least 50%, in particular at least 60%, in particular at least 70%, in particular at least 80%, in particular at least 90%. ### Claim 7 (depends on 1) The method according to claim 1, wherein only a proportion of the permeate stream is recycled to the feed side of said cross-flow filtration membrane. ### Claim 8 (depends on 1) The method according to claim 1, wherein both a proportion of the permeate stream and a proportion of the retentate stream are recycled to the feed side of said cross-flow filtration membrane. ### Claim 9 (depends on 1) The method according to claim 1, wherein the filtration system under operation is located under water. ### Claim 10 A filtration system comprising: a cross-flow filtration membrane having: a feed side fed with a feed stream, a permeate side wherein a permeate stream is recovered and a retentate side wherein a retentate stream is recovered, a hydraulic circuit Cp connecting the permeate side of said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane, said hydraulic circuit Cp allowing the recycling of a proportion of the permeate stream to the feed side of said cross-flow filtration membrane, and/or a hydraulic circuit Cr connecting the retentate side of said cross-flow filtration membrane to the feed side of said cross-flow filtration membrane, said hydraulic circuit Cr allowing the recycling of a proportion of the retentate stream to the feed side of said cross-flow filtration membrane, a reservoir containing a chemical product and said reservoir being connected to the hydraulic circuit Cp or the hydraulic circuit Cr or connected upstream of said cross-flow filtration membrane, a valve for setting the proportion of recycled permeate stream collected in the hydraulic circuit Cp, and/or a valve for setting the proportion of recycled retentate stream collected in the hydraulic circuit Cr. ### Claim 11 (depends on 10) The filtration system according to claim 10, wherein the cross-flow filtration membrane is a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane. ### Claim 12 (depends on 10) The filtration system according to claim 10, wherein the cross-flow filtration membrane is a ceramic membrane or an organic membrane. ### Claim 13 (depends on 10) The filtration system according to claim 10, wherein the chemical product is a biocide, an acid, a base, a cleaning agent such as surfactant agent, a detergent, a complexation agent or a scale dissolver, or a mixture thereof. ### Claim 14 (depends on 10) The filtration system according to claim 10, wherein said filtration system further comprises an injector for injecting the chemical product to the hydraulic circuit Cp or the hydraulic circuit Cr or upstream of said cross-flow filtration membrane. ### Claim 15 (depends on 10) The filtration system according to claim 10, wherein the hydraulic circuit Cp and/or the hydraulic circuit Cr comprises a booster pump or an eductor. ### Claim 16 (depends on 10) The filtration system according to claim 10 that is a subsea filtration system.