# US 2013/0153510 A1 · Method and system for treating aqueous streams > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0153510 A1 - Document ID: US20130153510A1 - Status: Published application - Kind: A1 - Application number: 13/810,839 - Filed: 2011-07-19 - Published: 2013-06-20 - Earliest claimed: 2010-07-20 - Assignees: Kemira Oyj - Inventors: Kaj Jansson; Iiris Joensuu; Marjatta Piironen; Jukka-Pekka Sirviö; Tapio Yrjänäinen - Web page: https://patentgrep.com/patent/US20130153510A1 ## CPC - C02F 1/5209: {Regulation methods for flocculation or precipitation} - B01D 21/01: using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10) - B01D 21/32: Density control of clear liquid or sediment, e.g. optical control {; Control of physical properties} - C02F 2209/001: Upstream control, i.e. monitoring for predictive control - C02F 2209/11: Turbidity - 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) - 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) ## Abstract The invention relates to a method and system for treating an aqueous stream having a first flow rate and containing solid matter exhibiting first settling properties, the method comprising adding a modifying agent to the aqueous stream at an addition rate sufficient to change the first settling properties of the aqueous stream to obtain a modified aqueous stream having solid matter exhibiting second settling properties different from the first settling properties; taking batchwise samples of the modified aqueous stream to a settling vessel having a volume; determining a settling property of the solid matter of the samples in the settling vessel; and conducting the modified aqueous stream to a separation unit in which solid matter is separated from the modified aqueous stream. The invention provides a convenient way of monitoring and/or controlling aqueous streams conducted for example to purification processes. ## Claims ### Claim 1 A method of treating an aqueous stream having a first flow rate and containing solid matter exhibiting first settling properties, comprising adding modifying agent to the aqueous stream at an addition rate sufficient to change the first settling properties of the solid matter of the aqueous stream to obtain a modified aqueous stream having solid matter exhibiting second settling properties different from the first settling properties; conducting a sample of the modified aqueous stream to a settling vessel having a volume; determining a settling property of the solid matter of the sample in the settling vessel; and conducting the modified aqueous stream to a separation unit in which solid matter is separated from the modified aqueous stream, wherein said conducting of the sample and determining of the settling property are carried out batchwise, sequentially in repeating cycles. ### Claim 2 (depends on 1) The method according to claim 1, wherein said taking the sample of the aqueous stream to the settling vessel is performed by withdrawing from the aqueous stream a sidestream having a second flow rate smaller than the first flow rate and conducting the sidestream to the settling vessel. ### Claim 3 (depends on 2) The method according to claim 2, wherein prior to said determination of the settling property of the solid matter of the sample in the settling vessel, interrupting said sidestream operating a valve in the sidestream. ### Claim 4 The method according to any of the preceding claims, comprising depending on the determined settling property of the solid matter of the sample in the settling vessel, controlling the addition rate and/or type of the modifying agent. ### Claim 5 (depends on 1) The method according claim 1, comprising predicting the settling property of the modified aqueous stream from which solid matter is separated in the separation unit based on the settling property of the solid matter in the sample determined in the settling vessel. ### Claim 6 (depends on 1) The method according to claim 1, wherein the determining of the settling property of the solid matter present in the settling vessel comprises measuring locally the turbidity or solids content of the sample in the settling vessel after a predefined period of settling time. ### Claim 7 (depends on 1) The method according to claim 1, wherein the aqueous stream is selected from the group of industrial or municipal wastewaters and effluents. ### Claim 8 (depends on 1) The method according to claim 1, wherein the modifying agent is selected from coagulants and flocculants, preferably selected from water-soluble salts or anionic, nonionic and cationic polyelectrolytes of uni- or multivalent cations, such as sodium, calcium, magnesium, iron, aluminum, natural products such as starch, semi-synthetic polymers such as cationic starch and synthetic polymers such as acrylic polymers, polyamines, polyethylene oxides and allylic polymers, or a mixture thereof. ### Claim 9 (depends on 1) The method according to claim 1, wherein the modifying agent is added in a sufficient amount to significantly reduce the settling time of the solid matter so as to obtain a second settling time which is shorter than the first settling time. ### Claim 10 (depends on 1) The method according to claim 1, wherein the solid matter is selected from organic matter, inorganic matter, biological matter and combinations thereof. ### Claim 11 (depends on 1) The method according to claim 1, wherein a second modifying agent is added to the aqueous stream at a second addition point which is placed preferably downstream of the point at which said sample is taken. ### Claim 12 (depends on 11) The method according to claim 11, wherein the second modifying agent is selected from coagulants or a flocculants, preferably selected from water-soluble salts or anionic, nonionic and cationic polyelectrolytes of uni- or multivalent cations, such as sodium, calcium, magnesium, iron, aluminum, natural products such as starch, semi-synthetic polymers such as cationic starch and synthetic polymers such as acrylic polymers, polyamines, polyethylene oxides and allylic polymers or a mixture thereof. ### Claim 13 (depends on 1) The method according to any of the preceding claims claim 1, wherein the separation unit is a sedimentation basin or flotation unit having a volume. ### Claim 14 (depends on 13) The method according to claim 13, wherein the ratio of the volume of the settling vessel to the volume of the separation unit is 1/100 to 1/10,000,000, in particular about 1/1,000 to 1/1,000,000. ### Claim 15 (depends on 1) The method according to claim 1, comprising determining the settling property of the solid matter in the settling vessel sequentially by providing a fresh sample from the aqueous stream to the settling vessel between the measurements. ### Claim 16 (depends on 15) The method according to claim 15, wherein the measurement sequence is repeated 1 to 200, in particular 1 to 100, preferably 1 to 20 times/h. ### Claim 17 (depends on 1) The method according to claim 1, wherein the settling property is turbidity measured using radiation e.g. in the range of UV, visible or IR wave length. ### Claim 18 (depends on 1) The method according to claim 1, wherein the settling vessel comprises a bottom and a top and the settling property is determined using a sensor comprising a sensor head positioned at a distance from the bottom of the settling vessel and at a distance from the top of the settling vessel. ### Claim 19 (depends on 1) The method according to claim 1, wherein each sample batch is allowed to settle in the settling vessel. ### Claim 20 (depends on 1) The method according to claim 1, wherein the settled turbidity or settling time of each of the samples is determined. ### Claim 21 (depends on 20) The method according to claim 20, wherein said addition of the modifying agent is controlled in response to the settled turbidity or settling time. ### Claim 22 (depends on 1) The method according claim 1, comprising providing a proportionality factor or function relating the settled turbidity or settling time between the settling vessel and an outlet of the separation unit, controlling, based on the determined settling property and said proportionality factor or function, the addition rate and/or type of the modifying agent so that a desired settled turbidity or settling time is achieved in the outlet of the separation unit. ### Claim 23 A water treatment system comprising a separation unit for separating solid matter from an aqueous suspension fed to the separation unit, a feed channel for feeding the aqueous suspension to the separation unit, means for adding modifying agent to the aqueous stream at an addition point in the feed channel, a settling vessel, means arranged at said feed channel for sequentially conducting samples of the aqueous suspension batchwise to the settling vessel in repeating cycles, means for determining at least one settling property of solid matter contained in the samples in the settling vessel, and optionally, means for controlling addition rate and/or type of the modifying agent. ### Claim 24 (depends on 23) The water treatment system according to claim 23, wherein the separation unit is a sedimentation basin or floatation tank, the means for conducting a sample of the aqueous suspension to the settling vessel comprise a sidestream channel connected to the feed channel and means for sequentially taking samples batchwise from the feed channel to the settling vessel, said means for determining at least one settling property of solid matter contained in the sample in the settling vessel are adapted to determine the turbidity or solid matter content of the sample after a predefined period of settling. ### Claim 25 (depends on 23) The water treatment system according to claim 23, being adapted to perform a method of treating an aqueous stream having a first flow rate and containing solid matter exhibiting first settling properties, comprising adding modifying agent to the aqueous stream at an addition rate sufficient to change the first settling properties of the solid matter of the aqueous stream to obtain a modified aqueous stream having solid matter exhibiting second settling properties different from the first settling properties; conducting a sample of the modified aqueous stream to a settling vessel having a volume; determining a settling property of the solid matter of the sample in the settling vessel; and conducting the modified aqueous stream to a separation unit in which solid matter is separated from the modified aqueous stream, wherein said conducting of the sample and determining of the settling property are carried out batchwise, sequentially in repeating cycles.