Air agitated high-density clarifier technology 

Air agitated high-density clarifier technology

1. Clarifier Overview

Coagulation treatment process of water and wastewater includes mixing of water and chemicals, flocculation reaction and flocculation

There are three stages of separation of body and water. The clarifier is a special equipment to complete the above three processes.

The medium used to intercept and separate impurity particles in the clarifier is suspended sludge layer (or called floc layer, mud layer and sludge layer). In the clarifier, the sludge is lifted up and kept in a uniformly distributed suspended state, forming a high concentration of stable activated sludge in the clarifier

The concentration of suspended solids in this layer is about 3g/L-10g/L or higher. The raw water flows from bottom to top in the clarifier, and the sludge layer can be in a dynamic equilibrium state in the upflow due to gravity.

When the raw water passes through the sludge suspension layer, the suspended solids in the raw water will be blocked by the sludge suspension layer using the contact flocculation principle, so that the water can be clarified. Clear water is collected in the upper part of the clarifier. The contact flocculation process is the basic function of quartz sand filtration, so the clarifier plays the role of flocculation, adsorption and filtration at the same time.

The rising velocity of sludge suspension layer is related to the volume and concentration of sludge, therefore, correct selection

Increase the flow rate and maintain a good sludge suspension layer, which is the basis for the clarifier to achieve better treatment effect

These Conditions.

At present, the commonly used clarifiers in wastewater treatment include mechanical accelerated clarifier, hydraulic circulating clarifier, suspension clarifier, pulse clarifier and high-density clarifier

ATIFLO of DENSADEG and OTV.

All the above clarifiers are used to treat suspended solids and

If the mud layer stays in the system for a long time, anaerobic sludge corruption will occur

Gas production floats up and so on. Only in the process system of adding powdered activated carbon, its solid-liquid separation

And the effluent effect is better than that of other sedimentation units. See the Water Supply and Drainage Design Manual for details.

2. Air agitated high-density clarifier

On the basis of referring to the existing clarifier, an air agitated high-density clarifier is designed.

By adding inorganic adsorption flocculant, a high-density active mud layer is formed, which has the following advantages:

1) The amount of air stirred by air is one tenth of the treated water, which can keep the water dissolved

The oxygen concentration is about 7mg/L to avoid anaerobic hydrolysis process and prevent mud gas from floating.

2) After adding inorganic adsorption flocculant, dissolved organics are removed through adsorption on the basis of removing suspended and colloidal organics in the flocculation process, which improves the removal efficiency. The true density of inorganic adsorption flocculant is about 2g/cm3, which increases the density of flocs and is conducive to solid-liquid separation.

3) The formed high-density active mud layer and mud itself have a true density of twice that of water, which becomes a high-density clarifier.

4) At the same time, complete the three processes of flocculation, adsorption and filtration.

5) If the combination of chemical ammonia and nitrogen removal agents for MAP is added, nitrogen, phosphorus and COD can be removed simultaneously.

6) Intelligent aerator is used in aeration area.

7) The mud concentration is controlled automatically.

8) After the active mud is formed, the dosage of inorganic adsorption flocculant is generally 3mg/L.

3. Scope of application

1) . Bid submission of urban sewage plants;

2) Advanced treatment of urban sewage plants;

3) Purification of black and odorous water;

4) Sewage treatment in small towns;

5) Water supply micro pollution treatment;

6) . Upgrading of industrial wastewater;

7) Treatment of high concentration organic wastewater;

8) Security unit at the end of processing flow.

4. Principle

See the schematic diagram for air stirring high-density clarifier.

5. Design parameters

As the advanced treatment unit of urban sewage plant, after the formation of active mud

1mg/L COD requires 0.3mg/L inorganic adsorption flocculant. Activated mud is a mixed liquid formed by microorganisms and inorganic adsorption flocculants, which has the functions of biochemical, flocculation and adsorption. When the effluent from the secondary sedimentation tank of urban sewage flows from Class I B (COD 60mg/L)

When Grade A is mentioned (COD 50mg/L), the dosage of inorganic adsorbent flocculant is

３ｍｇ／Ｌ。

6. Design and selection

The tank body is a rectangular reinforced concrete structure. Due to the limitation of pool depth, the pool width

B is set as 10600mm, and the pool length L can be optional, but it is better not to exceed 40m,

Otherwise, the uniformity of water distribution is not easy to control. The rising velocity of sedimentation area is 8m/h, per meter

The sedimentation area of the tank length is 8m2, and the water yield per meter of tank length is 64m3/h.