Question: What Makes A Good Coagulant?

What is the most commonly 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..

Why does pH affect coagulation?

At varying sample pH values, the coagulation process may suffer from less than optimum ions being formed in solution. … 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.

What does coagulant mean?

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.

Does alum affect pH?

While alum and ferric-based coagulants are acidic in nature and produce a drop in pH when added to wastewater, their main purpose is to neutralize electrical charges of fine particles in water and clump them together.

What is a good coagulant?

Inorganic coagulants such as aluminum and iron salts are the most commonly used. When added to water, these highly charged ions to neutralize the suspended particles. The inorganic hydroxides that are formed produce short polymer chains which enhance microfloc formation.

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 are the characteristics of good coagulant?

There are three key properties of a coagulant :Trivalent cation : As indicated in the last section, the colloids most commonly found in natural waters are negatively charged, hence a cation is required to neutralize the charge. … Nontoxic : This requirement is obvious for the production of a safe water.More items…

How can I improve my coagulation?

Water Treatment 101: 6 Tips for Improving Coagulation, Flocculation and ClarificationUse the correct polymer or coagulating chemicals. … Keep injection point close. … Slow mixing is good mixing. … Velocity gradient is important. … Keep an eye on temperature. … Balance the velocity.

Is coagulation good or bad?

Blood clotting is a natural process; without it, you would be at risk of bleeding to death from a simple cut. Blood clots inside the cardiovascular system are not always so welcome. A clot in the coronary arteries near the heart can cause a heart attack; one in the brain or the arteries serving it, a stroke.

What is the difference between a coagulant and a flocculant?

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.

Why is coagulant added to water?

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.

What does a coagulant do?

Coagulants work by creating a chemical reaction and eliminating the negative charges that cause particles to repel each other. The coagulant-source water mixture is then slowly stirred in a process known as flocculation.

What is the most commonly used coagulant in water treatment?

Aluminum and iron salts are the most commonly used inorganic coagulants in the wastewater treatment settings. These include based aluminum metals (aluminum chloride, aluminum sulfate, sodium aluminate) and iron based metals (ferrous sulfate, ferric sulfate, ferric chloride) [13, 17, 18].

What is the impact of coagulant dosing on pH?

As more coagulant was added, more particles could be destabilized throughout charge neutralization and efficient collisions, which led to the increase of aggregation at the initial aggregation. However, there was a various drop in the coagulation rate when the dosage was up to 7.5 mg/L under lower pH.

What chemicals are used to adjust pH?

The most common chemicals used for neutralizing acids or bases are sodium hydroxide (50%) and sulfuric acid (98%). To raise the pH of an acidic liquid, sodium carbonate (soda ash), ammonium hydroxide, calcium hydroxide (lime) or magnesium hydroxide can also be used.