Application of Flocculant in Water Treatment

Water is the source of life and an important guarantee for social and economic development. However, the industrialization process and population growth have led to increasingly severe water pollution, posing a threat to human health and the ecological environment. Therefore, water treatment technology plays a crucial role in ensuring water resource security. Among numerous water treatment technologies, flocculation sedimentation method is widely used in fields such as drinking water treatment, industrial wastewater treatment, and municipal sewage treatment due to its economic and efficient advantages. And Flocculant, as the core material of flocculation sedimentation method, plays a crucial role in the treatment effect.

The basic principle of Flocculant precipitation method

The basic principle of flocculation precipitation method is to use flocculant chemical to neutralize or adsorb the surface charges of suspended particles and colloidal particles in water, reduce their stability, and cause them to agglomerate with each other to form larger flocs. Then, they are separated and removed from water through precipitation or filtration. Suspended particles in water usually carry negative charges, which hinder their aggregation. The function of Flocculant is to eliminate or reduce the repulsive force between particles and promote their aggregation.

At present, commonly used Flocculants are mainly divided into two categories: inorganic Flocculants and organic Flocculants

Inorganic flocculant chemicals for water treatment mainly include aluminum salts, iron salts, and their polymers, such as aluminum sulfate, polyaluminum chloride, ferric chloride, etc. These inorganic flocculants generate highly positively charged multinuclear complexes through hydrolysis, which can effectively neutralize the negative charge of suspended particles and form a "bridge" connecting multiple particles, promoting the formation of flocs. The advantages of inorganic Flocculant are low cost and easy accessibility, but there are also some issues with its use, such as generating a large amount of sludge, large pH changes, and strong corrosiveness.

Organic Flocculant includes natural organic polymer Flocculant and synthetic organic polymer Flocculant

Natural organic polymers, such as starch and cellulose, have the advantages of being non-toxic and biodegradable, but their flocculation effect is usually not as good as synthetic organic polymers, such as water flocculant. Synthesize organic polymers such as polyacrylamide and its derivatives, which have high molecular weight and multiple functional groups, and can exert flocculation effects through various mechanisms such as adsorption bridging and charge neutralization. The advantages of synthesizing organic polymer Flocculant are good flocculation effect, low dosage, and small sludge production. However, its potential toxicity and non biodegradability have also attracted people's attention.

Choosing the appropriate Flocculant is the key to ensuring the effectiveness of flocculation and sedimentation

The factors that affect the selection of floc water treatment include water quality characteristics (such as turbidity, chromaticity, pH value, suspended solids concentration, etc.), treatment objectives, economic costs, and environmental impacts. In practical applications, it is often necessary to determine the optimal type and dosage of Flocculant through experimental testing, such as beaker experiments. In addition, inorganic and organic Flocculants can be combined to leverage their respective advantages, improve treatment efficiency, and reduce treatment costs.

With the increasing awareness of environmental protection and the continuous development of water treatment technology, research on Flocculant is becoming more and more in-depth. New types of Flocculant, such as modified natural polymer Flocculant and biological Flocculant, are gradually becoming a research hotspot. These new Flocculants are expected to overcome the shortcomings of traditional Flocculants and achieve more efficient and environmentally friendly water treatment.

In summary, Flocculant plays an important role in water treatment. With the advancement of technology and the increasing demand for environmental protection, research and application of Flocculant will continue to deepen, making greater contributions to ensuring water resource security.

Flocculant  FAQs

What is the main working principle of Flocculant?

Flocculant uses charge neutralization and bridging to destabilize colloidal particles in water and form larger flocs. It is mainly divided into two categories: inorganic Flocculant (such as polyaluminum chloride PAC) and organic polymer Flocculant (such as polyacrylamide PAM). Inorganic Flocculant achieves particle aggregation through charge neutralization, while organic polymer Flocculant mainly achieves particle aggregation through bridging of molecular chains.

How to choose the appropriate type of Flocculant?

Choosing Flocculant requires consideration of the following factors:

Water quality characteristics (such as pH value, turbidity, colloidal charge properties)

Processing process requirements (such as sedimentation rate, sludge volume)

economic cost

Subsequent processing requirements

Usually, a beaker test is conducted first to determine the optimal type and dosage.

What are the types of polyacrylamide (PAM)? How to choose?

PAM is mainly divided into:

Cationic type: suitable for negatively charged organic sludge

Anionic type: suitable for inorganic suspensions

Non ionic type: suitable for situations with large pH changes

When selecting, factors such as suspended solids properties and pH value should be considered, and the optimal model should be determined through experiments.

How to control the dosage of Flocculant?

The optimal dosage needs to be determined through experimentation, and the usual control principle is:

Inorganic Flocculant: 10100mg/L

Organic polymer Flocculant: 0.110mg/L

Excessive addition can cause the colloid to become more stable, which in turn reduces the effectiveness of the treatment. It is recommended to use an automatic dosing system for precise control.

What are the precautions when using Flocculant?

The main precautions include:

1) Dissolving configuration: Organic polymer Flocculant needs to be prepared into a 0.1% 0.5% solution first

2) Mixing conditions: Rapid mixing to evenly disperse the medication

3) Reaction time: Ensure sufficient coagulation time

4) Water quality impact: Temperature, pH value, etc. can affect the effect

5) Safety protection: Avoid direct contact, especially with powdered products

6) Environmental requirements: Some PAM monomers are toxic and residual levels need to be controlled