How do you test a jar?
How do you test a jar?
Samples of water to be treated are placed in six jars. Various amounts of chemicals are added to each jar, stirred, and the settling of solids is observed. The lowest dose of chemicals that provides satisfactory settling is the dose used to treat the water.
Which coagulant is used in the jar test?
The choice and dosing of the chemical coagulants derive in fact from the results of the laboratory Jar test, which mimics full-scale operation in water treatment plants. The most used coagulants are Lime (calcium hydroxide), Alum (aluminum sulphate) and Iron salts (ferric or ferrous).
What is the purpose of a jar test?
Jar testing is a pilot-scale test of the treatment chemicals used in a particular water plant.It simulates the coagulation/flocculation process in a water treatment plant and helps operators determine if they are using the right amount of treatment chemicals, and, thus, improves the plant’s performance.
What is optimum pH in jar test?
While a pH of 8.5 is normally recommended for the polishing effect — the pH value will vary depending on the presence of chelating and/or complexing agents in the wastewater. A jar test procedure as described above can help to establish the optimum pH within the 7.5 to 11 range.
Why lime is added with alum in jar test?
1. The purpose of lime is to create a stable pH environment – the ideal pH for iron alum environment is in the range of 7.5 – 8.5. In this environment, the flocculation is in the most perfect state and the flocculation time is the fastest. Therefore, lime is a factor that is dependent on iron alum.
How do you test a soil jar?
Reading Your Soil Texture Jar Test The heaviest material, including gravel or coarse sand, will sink to the very bottom, with smaller sand on top of that. Above the sand you’ll see silt particles, with clay at the very top of the jar.
What is the purpose of rapid mixing in jar test?
Rapid mixing aims to instantly and efficiently disperse coagulant species into raw water, before flocculation, sedimentation, and filtration processes.
What is the purpose of varying pH in the jar test?
How does pH affect coagulation and turbidity?
pH EFFECTS pH that is too low may not allow the coagu- lation process to proceed, while high pH can cause a coagulated particle to redisperse. The size of the coagulated particles is also affected by pH, which, in turn, determines the density of the flocculated slime and its tendency and rate of settling out.
How does ferric chloride work as a coagulant?
Ferric chloride (FeCl3) is the most common iron salt used to achieve coagulation. Its reactions in the coagulation process are similar to those of alum, but its relative solubility and pH range differ significantly from those of alum. Both alum and ferric chloride can be used to generate inorganic polymeric coagulants.