What are flocculant chemicals and how do they work?
Various industries and water supplying municipalities need access to clean water, and flocculant chemicals are a perfect solution for treating water. Flocculants are compounds that help small particles in a water clump together to form a floc, which rises to the surface or settles to the bottom, from where it may be readily removed.
What is flocculation in wastewater treatment?
Flocculation is a water treatment technique in which particles combine to create bigger clusters, or flocs, which are then removed from the water. This process might happen naturally or with the help of chemical agents. It is a widespread method of wastewater treatment, stormwater treatment, & purification of drinking water.
What is the coagulant added to water During flocculation?
In Plantas piloto de tratamiento de agua ,a coagulant, such as aluminum sulfate, is added to the water during the first step of flocculation. Moreover, the negatively charged solid granules suspended in the water are neutralized by the coagulant molecules that are positively charged.
What is the main ingredient in pool flocculant?
The main ingredient in pool (or spa) flocculants is aluminum sulfate. Clarifiers are often confused with Flocculents, which is similar but works differently.
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 chemicals are used in flocculation?
Aluminum sulfate or alum (Al2(SO4)3), ferric chloride (FeCl3) and ferric sulfate (Fe(SO4)3) are the most widely used flocculants [1, 70]. These flocculants have a long history of use in removing colloidal particles from water and wastewater [15, 17].
What is the main ingredient in pool flocculant?
The main ingredient in pool (or spa) flocculants is aluminum sulfate. Clarifiers are often confused with Flocculents, which is similar but works differently.
What is flocculant agent?
Flocculating agents are chemical additives that cause suspended solids to form aggregates called flocs. These agents are used in water treatment, municipal and industrial waste treatment, mineral processing, and papermaking. Flocculating agents are either inorganic salts or water-soluble organic polymers.
How do you make flocculant powder?
Prepare your coagulant–flocculant solution by adding one quarter teaspoon of alum powder to about three teaspoons of tap water. (You might have to heat the solution in the microwave to get the powder dissolved.) Stir the solution until all the alum powder is dissolved.
Is Surfactant a flocculating agent?
b) Surfactants Both ionic and non-ionic surfactants are capable of doing flocculation of the suspended particles. At a particular concentration, the surfactants trim down the surface free energy by reducing the interfacial tension between the liquid medium and solid drug particles.
Is clarifier the same as flocculant?
The main difference between the flocculant and pool clarifier is where the clumped particles go. Clarifier keeps the bounded matter at the top of the pool to be grabbed by the pool filter. Meanwhile, pool floc snags the particles, assembles them, and then sinks them to the bottom of the surface.
Is phosphate remover the same as clarifier?
A: This phosphate remover is a pool clarifier.
Does baking soda raise pH?
Baking Soda (Sodium Bicarbonate) is used to raise alkalinity and also slightly raise pH. And Soda Ash (Sodium Carbonate) is used to raise pH and slightly raise alkalinity. For example, getting a pH reading around 7.2 to 7.6 in 10,000 gallons (37,854 liters) of pool water would take roughly 21 pounds of baking soda.
Is calcium hydroxide a flocculating agent?
One significant application of calcium hydroxide is as a flocculant, in water and sewage treatment. It forms a fluffy charged solid that aids in the removal of smaller particles from water, resulting in a clearer product. This application is enabled by the low cost and low toxicity of calcium hydroxide.
Is alum a flocculant?
Alum, is a short term for aluminum sulfate, it works as a flocculant in your commercial pool, meaning that it attracts and traps suspended particles in the water and then sinks them to the bottom of the pool so that these particles can be vacuumed to waste.
What is flocculant liquid?
Flocculant is a clarifying agent that constricts the small particles in the water to the flocks, which sink to the bottom or stick to the sand filter. Flocculant is available as both liquid and tablets. Flocculant in liquid form is poured directly into the pool.
What is flocculant used 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.
What is a coagulant and floculant?
What Is A Coagulant And Flocculant? Flocculants and Coagulants for Wastewater are used in every industrial water treatment process. Wastewater slurries exhibit a range of particle sizes and charge requirements. Optimum Coagulant and Flocculant treatment are used to separate solids from wastewater and requires specific dosages.
What is the difference between anionic and cationic flocculants?
Generally speaking, anionic flocculants are used to catch mineral particles while cationic flocculants can capture ...
What are the two categories of coagulants used in wastewater pretreatment?
Chemical coagulants used in industrial wastewater pretreatment fall into one of two categories: organic and inorganic coagulants.
What are some examples of organic coagulants?
Examples of common organic coagulants include polyamines and polyDADMACs, as well as melamine formaldehydes and tannins.
What is the mechanism that removes sludge from water?
This is referred to as the “sweep-floc” mechanism. While effective, this process adds to the overall sludge volume that needs to be removed from the water.
Is coagulant effective on raw water?
Inorganic coagulants are both cost-effective and applicable for a broad variety of water and wastewater. Inorganic coagulants are particularly effective on raw water with low turbidity and will often treat this type of water when organic coagulants cannot.
Lab Effectiveness, Field Effectiveness, and Health Impact
The flocculant/disinfectant powder P&G™ has been proven to remove the vast majority of bacteria, viruses, and protozoa, even in highly turbid waters. P&G™ has also been documented to reduce diarrheal disease from 90% to less than 16% incidence in five randomized, controlled health intervention studies.
Implementation Examples
Social marketing organizations, such as the NGO Population Services International, sell P&G™ sachets in multiple countries.
Economics and Scalability
Each sachet of P&G™ is provided to global emergency relief organizations or non-governmental organizations at a cost of 3.5 US cents, not including shipping from Pakistan by ocean container. Transport, distribution, education, and community motivation can add significantly to program costs.
Additional Resources
For more information about flocculant/disinfection systems for developing countries visit:
Inorganic flocculants
Inorganic compounds are comprised of molecules that do not contain carbon. These compounds make up some of the most widely used flocculation agents on the market.
Organic flocculants
Organic flocculants include carbon-based molecules and may be biological in nature. The following agents may represent a more efficient alternative to inorganic flocculants in some cases.
What are some examples of flocculants?
Examples of ChemTreat flocculants include low-, medium-, and high-molecular weight polymers.
What is a coagulant in water treatment?
Water treatment coagulants are comprised of positively charged molecules that, when added to the water and mixed, accomplish this charge neutralization. Inorganic, organic, or a combination of both coagulant types are typically used to treat water for suspended solids removal. When an inorganic coagulant is added to water containing ...
What polymers act similarly to inorganic coagulant products?
Melamine Formaldehydes and Tannins. These all-organic polymers act similarly to the inorganic coagulant products in that they not only coagulate the colloidal material in the water, but also contribute their own precipitated floc. This sweep-floc precipitate readily adsorbs organic materials such as oil and grease.
What is the most widely used class of organic coagulation chemicals?
Polyamine and PolyDADMAC. These are the most widely used classes of organic coagulation chemicals. They function by charge neutralization alone, so there is no advantage to the sweep-floc mechanism. Polyamines will generally treat higher turbidity raw water (approximately >20 NTU) effectively.
What is ferric sulfate?
Iron coagulation works similarly to aluminum coagulants but the cost may vary based on the local supply source. Ferric sulfate is the more commonly used, but ferrous sulfate is typically used in applications where a reducing agent or excess soluble iron ions are required .
When to use organic coagulant?
Organic coagulant is generally used when a reduction in sludge generation is desired. Furthermore, blended organic and inorganic chemicals are often more effective than either organic or inorganic chemicals alone. The correct blend can often combine the advantages of using the inorganic coagulant sweep-floc mechanism with ...
Is sludge hazardous to water?
For influent or raw water applications where the sludge is generally non-hazardous, the penalty for creating more sludge with higher water content is small. For wastewater applications with hazardous sludge, the economic penalty can be significant.
Why are polymers added to flocculants?
They are added as part of the flocculation process to help strengthen and increase the settling weight of the floc. Polymers can be either natural or synthetic. Natural polymers also date back to ancient times, with Sanskrit literature from around 2000 BC referencing the use of crushed nuts to clarify water.
What is the purpose of coagulation and flocculation?
Coagulation and flocculation are essential components of both drinking water and wastewater treatment. They provide a reliable process for treating water turbidity (the cloudiness or haziness of a fluid typically invisible to the naked eye) which is a key test of water quality.
What is the difference between flocculation and coagulation?
Coagulation and flocculation are two, separate, crucial parts of water and wastewater treatment. Coagulation destabilises the minute suspended particles by static charge neutralisation, while flocculation helps them to bind together to form much bigger morphologies, so they can be more easily separated from the liquid phase.
What coagulants remove suspended solids?
Organic coagulants. Both polyamine and poly-DADMAC coagulants have been proven to be very effective at removing most suspended solids. Tannates are particularly good at oils and fats. Enable relatively low charge density to neutralise lower charged suspended particles, more effectively.
What are the two types of coagulants?
Types of coagulants. Today, there are two types of coagulants that are most commonly used in water and wastewater treatment. Organic and inorganic. Inorganic coagulants include: Iron coagulants - e.g. ferric sulphate, ferrous sulphate, ferric chloride and ferric chloride sulphate. Organic coagulants include:
How long does it take for a suspended particle to settle out of the water?
This causes them to remain suspended rather than clumping together and settling out of the water. They might take days or even up to centuries to settle out! Coagulation and flocculation are two separate processes, used in succession, to overcome the forces stabilising the suspended particles. While coagulation neutralises the charges on ...
When were coagulants first used?
The use of coagulants for treating water goes all the way back to around 2000 BC when the Egyptians used almonds, smeared around vessels, to treat river water. These larger ‘clumps’ of particles are called micro-flocs and still cannot always be seen by the naked eye.
Why do flocculants work?
These two basic concepts are the reasons that flocculants work. When the particles come together, they get heavier. When they get heavier, the water molecules cannot push them around as easily as they used to, and gravity pulls them to the bottom of the water container. The result is water with less dirt in it!
Why do flocculants accumulate mass?
Because they are so large, small particles can get trapped in the curves of the polymer causing them to accumulate a mass heavy enough to prevent their retention in solution. Many other flocculants are currently used in water treatment today and even more are being studied by engineers and researchers around the world.
How does pH affect flocculant performance?
Additionally, the water's pH can affect the performance of a flocculant. The pH scale (see Figure 7) is used to determine how acidic or basic the water is. Most flocculants work best at neutral conditions (pH 7) while some work independently of the pH.
Why do colloids settle out of water?
Another reason that colloids take a long time to settle out of water is surface charges. Surface charges can form on a particle in several ways.
What is the measurement of the cloudiness of water?
In this lesson, we focus on the removal of solids. Turbidity —To measure water cleanliness prior to consumption, we use the concept of turbidity. Derived from the word turbid, turbidity is a measurement of the "cloudiness" of water. It essentially tells us the amount of solids in the water.
What are the contaminant types in water?
Several contaminant types are found in water including chemicals (such as salts and sugars), microorganisms (such as bacteria and algae), and solids (such as clay and sand). Most of these contaminants are removed in the water treatment cycle. In this lesson, we focus on the removal of solids.
What are some examples of settling solids?
Examples of settling solids are sand and small rocks.
What is coagulation in water treatment?
Coagulation is one of the preliminary steps in cleaning water and when chemicals are used, a few design practices regarding the storage tank can bring safety, longevity and operational efficiency. Understanding how coagulants work in water treatment, what to do about the sludge that accumulates, and how to minimize risk will help you configure an effective and efficient coagulation tank system.
What are floating particles in water?
These floating particles, which are too light to settle by gravity, are called Colloids. They are made up of both non-organics (such as clay or silt) and organics (such as algae or bacteria). When ingested by humans, some of the organic bacterias can be fatal.
Lab Effectiveness, Field Effectiveness, and Health Impact
- The flocculant/disinfectant powder P&G™ has been proven to remove the vast majority of bacteria, viruses, and protozoa, even in highly turbid waters. P&G™ has also been documented to reduce diarrheal disease from 90% to less than 16% incidence in five randomized, controlled health intervention studies. P&G™ also removes heavy metals—such as arsenic...
Benefits, Drawbacks, and Appropriateness
- The benefits of Flocculant/Disinfectant Powder are:
1. Proven reduction of bacteria, viruses, and protozoa in water 2. Removal of heavy metals and chemicals 3. Increased free chlorine protection against contamination 4. Proven reduction of diarrheal disease 5. Visual improvement of water and acceptability 6. Transport of sachets easy … - The drawbacks of Flocculant/Disinfectant Powder are:
1. Multiple steps are necessary—requires training or demonstration 2. Requires a lot of equipment (2 buckets, cloth, and a stirrer) 3. The higher relative cost per liter of water treated P&G™ is most appropriate in areas with a consistent supply chain for sachet resupply and in urban, rural, and e…
Implementation Examples
- Social marketing organizations, such as the NGO Population Services International, sell P&G™ sachets in multiple countries. Local organizations use the socially marketed P&G™ sachets in their own programming to provide safe drinking water. In western Kenya, students in schools are taught how and why to use P&G™, and safe water clubs treat drinking water for all the students…
Economics and Scalability
- Each sachet of P&G™ is provided to global emergency relief organizations or non-governmental organizations at a cost of 3.5 US cents, not including shipping from Pakistan by ocean container. Transport, distribution, education, and community motivation can add significantly to program costs. Sachets are generally sold at product cost recovery for 10 US cents each, for a cost of 1 U…
References
- Chiller TM, Mendoza CE, Lopez MB, Alvarez M, Hoekstra RM, Keswick BH, Luby SP. Reducing diarrhoea in Guatemalan children: randomized controlled trial of flocculant-disinfectant for drinking-water.external iconBull World Health Organ. 2006; Jan 84(1):28-35. Crump JA, Otieno PO, Slutsker L, Keswick BH, Rosen DH, Hoekstra RM, Vulule JM, Luby SP. Household based treatmen…
Additional Resources
- For more information about flocculant/disinfection systems for developing countries visit: 1. World Health Organization: Household water treatment and safe storageexternal icon 2. Procter and Gamble: Health Sciences Instituteexternal icon