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Definition. Flocculation – process during which particles, for example, of a soil, dispersed in a solution contact and adhere each another, forming clusters, flocks, flakes, or clumps of a larger size. The term originates from the word “floc,” which is the flake of precipitate that comes out of solution.
What do you mean by 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.
What is dispersion and flocculation?
Dispersion is when clay particles are kept separate from one another like opposite ends of a magnet. In fact, clay particles are very similar to the negative ends of a magnet. Flocculation is the process where individual clay particles are pulled together. This clumping is called AGGREGATION.
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.
How do you mix flocculant?
To optimize flocculant mixing system sizing, flocculant solutions are often designed to be mixed to 0.25-0.50% maximum concentration. Once dissolved, the flocculants will dilute readily with teed in water down stream of the flocculant feed pump to obtain the final target 0.1% concentration.
How long does flocculant take to work?
Flocculant, although fast-acting, will still need around 8-16 hours to work its magic. It’s easiest to do this overnight. The pump definitely needs to be off as you want the water to be still. The floc will have settled at the bottom of the pool and will require manual vacuuming to remove the debris.
Which ion causes dispersion in soil?
When the ratio of sodium to other ions at these exchange sites is high, clay particles are less tightly bound to each other and the soil aggregates easily disperse when the soil becomes wet.
What is an example of a flocculant?
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.
Is gypsum a flocculant?
Gypsum can coagulate or bridge clay particles, which accelerates settling. Flocculants should be used to prevent damage to sensitive water resources such as ponds, lakes and trout streams or whenever turbidity control is required. The best thing to do is a jar or bucket test using slightly varying rates of gypsum.
Can you use too much flocculant?
Flocculant is aluminum sulfate, which is designed to clump with the particles you’re trying to remove. But if you add too much, the flocculant will start to agglomerate with itself instead of those particles. These flocculant clumps will not drop to the pool floor and can clog up your filter.
Does lime Flocculate clay soil?
Lime is considered to be a soil conditioner. It can be used to raise the pH of a soil to make it less acidic. It will also flocculate clay particles so they will form crumbs rather than clods.
Why does clay clump together?
Most clay particles have a negative electrical charge. Like charges repel, so clay particles repel one another. Cations (positively charged molecules) can make clay particles stick together (flocculate).
When the soil is flocculated it means that the soil has a high amount of?
The lower the value of SAR (i.e., larger bivalent cation concentration), the more flocculated is the soil. Also, if the content of soluble salt is high (high ionic strength) the soil will flocculate, even at an elevated content of sodium ions (Walworth, 2006).
How is flocculation prevented?
Design contact times for flocculation range from 15 or 20 minutes to an hour or more, and flocculation requires careful attention to the mixing velocity and amount of mix energy. To prevent floc from tearing apart or shearing, the mixing velocity and energy are usually tapered off as the size of floc increases.
What is the purpose of flocculation?
Effect on Turbidity As with coagulation, the purpose of flocculation is not to directly reduce turbidity or suspended solids, but to prepare the solids for subsequent removal. Flocculation reduces the number of suspended solids particles as smaller particles combine to form larger ones.
What causes flocculation in soils?
Soil particles will flocculate if the amount of soluble salts in the soil is increased (increased EC), even if there is a lot of sodium. Soil particles may disperse if the amount of soluble salts in the soil is decreased (i.e. if EC is decreased).
Is flocculation good for soil?
In all but the sandiest soils, dispersed clays plug soil pores and impede water infiltration and soil drainage. Flocculation is important because water and oxygen moves mostly in large pores between aggregates moves mostly in large pores between aggregates. Also, plant roots grow mainly between aggregates.
What is flocculant made of?
The aluminum-based flocculants include aluminum sulfate, aluminum chloride, sodium aluminate, aluminum chlorohydrate, and polyaluminum chloride. The iron-based flocculants include ferric chloride, ferric sulfate, ferrous sulfate, and ferric chloride sulfate [15, 69].
What is the principle of flocculation?
Flocculation refers to the process used to bring the coagulated particles together so that they can combine to form larger, settleable, and filterable masses of particles called floc. Zeta potential is defined and its role in coagulation described.
What chemicals are used in flocculation?
Chemicals (coagulants) are added to the water to bring the nonsettling particles together into larger, heavier masses of solids called floc. 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 importance of soil pH in soil analysis?
A pH of 7 indicates a neutral soil. The pH is important because it influences the availability of essential nutrients. Most horticultural crops will grow satisfactorily in soils having a pH between 6 (slightly acid) and 7.5 (slightly alkaline).
Which are flocculating agent in soil?
Sodium silicate is specified as the de- flocculating agent in the present ASTM and AASHO standard methods of mechanical analysis. Sodium pyrophosphate and so- dium metaphosphate have been found ef- fective as deflocculating agents lor many types of soil (1, 5, 6).
What is flocculation value?
Flocculation value is defined as the minimum concentration required of an electrolyte to cause the coagulation or flocculation of a solution. Flocculation value is inversely proportional to the coagulating power of the ion.
