Features:

• Removal of dissolved substances (e.g. iron) by precipitation and flocculation  
• Sedimentation of the flocs in the lamella separator 

Tesca Precipitation and Flocculation Apparatus demonstrate the removal of dissolved substances by precipitation and flocculation with subsequent sedimentation.  
First, raw water is produced in a tank to contain dissolved metal (e.g. iron). A pump transports the raw  water to the precipitation tank. Here the precipitant is added (e.g. caustic soda). Due to the reaction of  the dissolved metal ions with the precipitant, insoluble metal hydroxides form (solids). From here the  water flows into a flocculation tank divided into three chambers. The purpose of flocculation is to  improve the sedimentation properties of the solids. By adding a coagulant in the first chamber the  repulsive forces between the solid particles are canceled out. The solid particles aggregate into flocs  (coagulation). To generate larger flocs, a flocculant is then added (flocculation). In the third chamber,  low flow velocities are present to prevent any turbulence. Turbulence would impede the formation of  flocs. The now well sedimentable flocs are then separated from the treated water in a lamella  separator. The treated water and the sedimented flocs (sludge) are collected in two tanks.  

Flow rate, temperature, and pH value are measured. In addition, the pH value in the precipitation  tank can be controlled. For measuring the conductivity an external meter is available. Samples can be  taken at all relevant points.  
Analysis technology is required to analyze the experiments. The choice of analysis technology depends  on the substances used. Trivalent metallic salts are usually well suited as coagulants. Common  flocculants are organic polymers.  

Specifications:

1. Precipitation and flocculation of dissolved substances (e.g. iron)  
2. Separate supply unit with tank and pump for raw water  
3. Precipitation tank with stirring machine  
4. Flocculation tank with 3 chambers and 4 stirring machines  
5. 3 metering pumps for chemicals  
6. Sedimentation of the flocs in the lamella separator  
7. Measurement of flow rate, temperature, and pH value 
8. Control of the pH value

Technical Specifications:
Tanks  
Raw water and treated water: each 300L  
Precipitation tank: 10L  
Flocculation tank: 45L  
Sludge tank: 15L  
Lamella separator  
Number of lamellas: 6  
The angle of inclination of lamellas: 60°  
Raw water pump  
Max. flow rate: 180L/h  
Max. head: 10m 
Metering pumps  
Max. flow rate: each 2,1L/h  
Max. head: each 160m  
Stirring machines  
Max speed: each 600min-1 
Measuring ranges  
Flow rate: 15…160L/h 
pH value: 0…14 
Temperature: 0…60°C 
Conductivity: 0…2000µS/cm  

Experiments:

1. Familiarization with precipitation and flocculation  
2. Effect of the pH value on precipitation  
3. Creation of a stable operating state  
4. Determination of the required metering quantities (precipitant, coagulant, flocculant)  
5. Functional principle of a lamella separator 

Requirements:
Mains Power 220 – 240V @ 50Hz, 1Ph