同济大学：《给水工程原理与技术》课程电子教案（课件讲稿）Mixing Coagulation - Flocculation

同海大学 TONGJI UNIVERSITY Lesson V:Mixing Coagulation/Flocculation Dr.TANG Yulin

Company name Dr. TANG Yulin Lesson V: Mixing Coagulation/Flocculation

d 同©大号 Tongji University 净水厂鸟敢图 Coagulant Cl2 Conventional 111111 Treatment Flocculation Filtration Sedimentation

Tongji University

同©大号 Tongji University Pumping Storage tanks station Flocculant Raw water reservoir Mixing tank Flocculation tank Particulate filter Consumer Raw water held Water is mixed 3As aggregates Water Water is stored in reservoir to with flocculant of floc settle out, undergoes before use by allow particulates they carry colloidal filtration consumers to settle particles out of Water is disinfected suspension by chlorination, ozone treatment, or exposure to Municipal Water Purification Plant

Tongji University Municipal Water Purification Plant

酒 同©大 Lake or Reservoir Tongji University Coagulation removee dirt and other partcles susponded in water.Alum and othor chemicals are added to water to form Sny sticky particies caled"floc"which attract the dirt particles.The combined weight of the dirt and the alum (foc)become heavy enough to sink to the bottom during sedimentation. Sedlmentation: The heawy particles (floc) sette to the Storage: bottom and the Wster is placed in clear water moves a closed tank or to fitration. roservoir for Disinfection:A small amount of chlorine is added or disinfoction to take some other disinfection method la used to kdl any place.The waler bactera or microorganisms that may be in the water. then fiows through pipes to homes and businesses in the community. F月tration:The water passes through fiters, some made of Souce:AWWA Drnking Water Week Blue Thumb Kt layers of sand. gravel,and charooal thet help remove even smaler particles

Tongji University

同©大学 Tongji University Application of Mixing in Water Treatment 1.Mixing of coagulants completely within water, 2.Blending of miscible liquids, 3.Flocculation of particles in water

Tongji University 1. Mixing of coagulants completely within water, 2. Blending of miscible liquids, 3. Flocculation of particles in water, Application of Mixing in Water Treatment

同©大学 Tongji University The mixing operations in water treatment can be classified as: 1)Continuous-rapid mixing (30sec), 2)Continuous mixing (on going)

Tongji University The mixing operations in water treatment can be classified as: 1) Continuous-rapid mixing (< 30sec), 2) Continuous mixing (on going)

同燎大学 Tongji University Each unit operation will be described separately below followed by a description of: 1)Types of mixers and flocculation devices, 2)Analysis of energy requirements for these operations

Tongji University Each unit operation will be described separately below followed by a description of: 1) Types of mixers and flocculation devices, 2) Analysis of energy requirements for these operations

同燎大学 Tongji University 1.Continuous Rapid Mixing Continuous rapid mixing is often used to mix coagulants within water. Applications include: 1.The blending of chemicals with water e.g.the addition of alum or iron salts prior to flocculation and settling or for dispersing chlorine and hypochlorite into water for disinfection. 2.The addition of chemicals to sludge to improve their dewatering characteristics

Tongji University 1. Continuous Rapid Mixing Continuous rapid mixing is often used to mix coagulants within water. Applications include: 1. The blending of chemicals with water e.g. the addition of alum or iron salts prior to flocculation and settling or for dispersing chlorine and hypochlorite into water for disinfection. 2. The addition of chemicals to sludge to improve their dewatering characteristics

月©大学 Tongji University Typical examples of the types of mixers used in water treatment facilities Mixing device Mixing time, (seconds) Applications/remarks Static in-line mixers, <1 Instantaneous mixing of chemicals like in-line mixers A13+,Fe3,Cl2,and cationic polymer High-speed induction <1 Same as the above mixers Pressurized water jets <1 In water treatment practice and for reclaimed water applications Turbine and propeller 2-20 Mixing of chemicals in solution feed mixers tanks <1 Chemicals to be mixed are introduced in Pumps the suction intake of the pump

Tongji University Typical examples of the types of mixers used in water treatment facilities Mixing device Mixing time, (seconds) Applications/remarks Static in-line mixers, in-line mixers < 1 Instantaneous mixing of chemicals like Al3+, Fe3+, Cl2，and cationic polymer High-speed induction mixers < 1 Same as the above Pressurized water jets < 1 In water treatment practice and for reclaimed water applications Turbine and propeller mixers 2-20 Mixing of chemicals in solution feed tanks Pumps < 1 Chemicals to be mixed are introduced in the suction intake of the pump

同森大学 Tongji University Mixer is consist of crossing bars installed inside a tube http://www.nt-outai.com/outai/pro.htm

Tongji University Mixer is consist of crossing bars installed inside a tube http://www.nt-outai.com/outai/pro.htm