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Flocculation is the process of formation of solid aggregates from small particles. Precipitation is the process of formation of an insoluble solid mass. The main difference between flocculation and precipitation is that flocculation forms floccules whereas precipitation forms precipitates.
What is the difference between flocculation and coagulation?
Flocculation is synonymous with agglomeration and coagulation / coalescence. Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle. Meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles.
What do you mean by flocculation?
Flocculation is a two-step particle aggregation process in which a large number of small particles form a small number large flocs. Step 1: Coagulation. Small particles usually carry negative surface charges that hinder aggregation and settling (1a).
What chemicals are flocculants?
A flocculants are usually organic chemicals added to wastewater to enhance flocculation, such chemicals are alum, aluminium chlorohydrate, aluminium sulphate etc.
Is alum a coagulant or flocculant?
To accomplish this, the water is treated with aluminum sulfate, commonly called alum, which serves as a flocculant. Raw water often holds tiny suspended particles that are very difficult for a filter to catch. Alum causes them to clump together so that they can settle out of the water or be easily trapped by a filter.
What two chemicals are commonly used as water coagulants?
Aluminum sulfate (alum) is the most common coagulant used for water purification. Other chemicals, such as ferric sulfate or sodium aluminate, may also be used.
Which are two chemicals used to purify water?
Chlorine and ozone are two chemicals used to purify water.
What’s a coagulant?
Coagulants are a substance which cause particles in a liquid to curdle and clot together. Coagulation treatment chemicals are used in effluent water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering.
How often can you use flocculant?
You can reuse a clarifier after 5-7 days, but if you’re constantly seeing cloudy water, there may be other problems. Adding too much flocculant can cause its own issues.
Why alum is commonly used coagulant?
To induce coagulation, a coagulant (typically a metallic salt) with the opposite charge is added to the water to overcome the repulsive charge and “destabilize” the suspension. For example, the colloidal particles are negatively charged and alum is added as a coagulant to create positively charged ions.
Does alum increase pH?
Ionic species present in alum solutions are highly dependent on the degree of reaction with hydroxyl ions. It is tempting to say that “the composition is pH-dependent.” However, in the vicinity of pH=4.3 the composition of alum solutions changes a great deal with very little change in pH.
What is the difference between filtration and flocculation?
Flocculation processes are always applied when impurities cannot be removed by sedimentation. By using the flocculation process, suspended and colloidal impurities are reduced to a form suitable for sedimentation so that they can be removed from the water by means of filtration or sedimentation devices.
How can flocculation be prevented?
When particles of a suspension come close together they can form aggregates called flocculates which will settle more rapidly. To prevent that we often coat the particle with a charged surfactant. The charge (Zeta potential) acts to keep the particles separate and prevent flocculation.
What is the principle of flocculation?
Coagulation – flocculation is physico-chemical process that facilitates the agglomeration of fine particles (colloids) contained in water to form a floc that can be easily filtered from water. Effluent (waste water) must be treated before it is discharged or before the water is re-used.
What are the 4 steps of water treatment?
These include: (1) Collection ; (2) Screening and Straining ; (3) Chemical Addition ; (4) Coagulation and Flocculation ; (5) Sedimentation and Clarification ; (6) Filtration ; (7) Disinfection ; (8) Storage ; (9) and finally Distribution. Let’s examine these steps in more detail.
What is denaturation and coagulation?
Denaturation is the permanent alteration of protein structures by heat, acid or agitation. Coagulation is the “setting” of protein when heat or acid is added. It traps liquids inside a solid. The pictures to the right are examples of foods that undergo denaturation and coagulation in their production process.
What are the side effects of alum?
Side effects of Alum The excessive amount of alum intake may cause breathing difficulty, facial puffiness, pricking sensation & small ulcers on the skin, chest/throat tightness, and burns rarely seen in some cases.
What is the purpose of flocculation?
Flocculation is a process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate. The method is widely used in water treatment plants and can also be applied to sample processing for monitoring applications.
Does precipitation mean denaturation?
Denaturation occurs because the bonding interactions responsible for the secondary structure (hydrogen bonds to amides) and tertiary structure are disrupted. The most common observation in the denaturation process is the precipitation or coagulation of the protein.
What is flocculant for?
Used in a wide range of industries and applications, flocculants help to remove suspended solids from wastewater by aggregating contaminants into flakes or “flocs” that float to the surface of the water or settle at the bottom. They can also be used for lime softening, sludge thickening, and solids dehydration.
Why is coagulation flocculation necessary?
Coagulation and flocculation are used to separate the suspended solids portion from the water. Suspended particles vary in source, charge, particle size, shape, and density. Coagulation and flocculation occurs in successive steps, allowing particle collision and growth of floc.
Is Lime a coagulant?
Lime (Ca(OH)2 or CaO): Lime, or calcium hydroxide, is predominantly used to adjust pH, but as a softener, it can also be used as a coagulant aid. The lime bonds with the other particles and increases the size/weight of the flocs which then increases the speed with which they settle out of the water.
Is coagulation and precipitation same?
Unlike coagulation and flocculation, the precipitation is carried out on a single phase system (homogenous solution), while coagulation and flocculation are employed on a two or more phase system. Coagulation and flocculation are often used together as a pair in a process to separate solids from a liquid.
What is precipitation in food?
The emergence of the insoluble solid from solution is called precipitation. Often the precipitate emerges as a suspension. Precipitates can form when two soluble salts react in solution to form one or more insoluble products.
Which coagulant is best?
Chemical Coagulants Used In Water Treatment
- Aluminum Sulfate (Alum) – One of the most commonly used water treatment chemicals in the world.
- Aluminum Chloride – A second choice to Alum as it is more expensive, hazardous and corrosive.
- Polyaluminum Chloride (PAC) & Aluminum Chlorohydrate (ACH)
