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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.
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.
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 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.
What is the process 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.
Why is alum a good coagulant?
The pH of the water plays an important role when alum is used for coagulation because the solubility of the aluminum species in water is pH dependent. If the pH of the water is between 4 and 5, alum is generally present in the form of positive ions (i.e., Al(OH)2+, Al8(OH)4+, and Al3+).
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.
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)
Which are two chemicals used to purify water?
Chlorine and ozone are two chemicals used to purify water.
Why is flocculation important?
Used water can contain significant amounts of suspended particulate matter, which often takes long to sediment. Flocculation expedites sedimentation and ensures efficient solid/liquid separation.
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 is an example of flocculation?
Flocculation and coagulation treatment chemicals are used in effluent wastewater water treatment processes for solids removal, water clarification, lime softening, sludge thickening, and solids dewatering. Examples of ChemTreat coagulation products include aluminum salts, iron salts, and polyelectrolytes.
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.
How is chloride removed from wastewater?
At high concentrations, chloride can harm fish and plant life. But there’s no easy and affordable way to remove chloride in wastewater. It would require reverse osmosis, the same process used to produce water for laboratory use, which is technically difficult as well as costly.
How is river water treated?
River water treatment is the process of removing contaminants from flowing or stagnant river water which includes physio-chemical treatment of water with the combination of conventional and advance treatment process like coagulation, flocculation, clarification, settling, filtration and disinfection of filter water to
What is the most used coagulant?
Iron and aluminium salts are the most widely used coagulants but salts of other metals such as titanium and zirconium have been found to be highly effective as well.
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 chemicals are flocculants?
A flocculants are usually organic chemicals added to wastewater to enhance flocculation, such chemicals are alum, aluminium chlorohydrate, aluminium sulphate etc.
What is the difference between flocculation and precipitation?
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.
How is water treated steps?
Water treatment
- Sedimentation – the water is stored in a large tank or a reservoir.
- Filtration – the water is sprayed onto specially-prepared layers of sand and gravel.
- Chlorination – chlorine gas is injected into the water to sterilise it.
What can be used as a flocculant?
The following natural products are used as flocculants:
- Chitosan.
- Isinglass.
- Moringa oleifera seeds (Horseradish Tree)
- Gelatin.
- Strychnos potatorum seeds (Nirmali nut tree)
- Guar gum.
- Alginates (brown seaweed extracts)
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’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 is wastewater cleaned?
Water School As wastewater enters the treatment plant, it is screened to remove non-sewage items such as rags, clothing, toothbrushes, or any other solids that might damage or clog the equipment. This material is sent to landfills. The sewage then moves into grit settling tanks where grit is removed to a landfill.
What is flocculation test?
Medical Definition of flocculation test : any of various serological tests (as the Mazzini test for syphilis) in which a positive result depends on the combination of an antigen and antibody to produce a flocculent precipitate.
