Commonly used drugs in sewage treatment

Polyacrylamide

Polyacrylamide (PAM) is a water-soluble polymer, insoluble in most organic solvents, has good flocculation, can reduce the frictional resistance between liquids, and can be divided into nonionic, anionic, cationic and There are four types of bisexuality.

Note on the use of cationic polyacrylamide:

1) The size of the floc: If the floc is too small, it will affect the speed of the drainage. If the floc is too large, the floc will restrict more water and reduce the degree of the biscuit. The size of the floc can be adjusted by selecting the molecular weight of the polyacrylamide.

2) Sludge characteristics: The first point is to understand the source, characteristics and composition of the sludge. Depending on the nature, sludge can be divided into organic and inorganic sludge. Cationic polyacrylamide is used for the treatment of organic sludge. The relative anionic polyacrylamide flocculant is used for inorganic sludge. When the alkalinity is strong, cationic polyacrylamide is used. When the acidity is strong, it is not suitable to use anionic polyacrylamide. High-time sludge usually has a large amount of polyacrylamide.

3) Floc strength: The floc should be stable and not broken under shearing action. Advancing the molecular weight of polyacrylamide or selecting a suitable molecular structure helps to improve floc stability.

4) Ionicity of polyacrylamide: For dewatered sludge, flocculants with different ionic degrees can be selected by small test first, and the suitable polyacrylamide can be selected, so that the effect of Zuijia flocculant can be obtained. It can also minimize the amount of drug added and save money.

5) Dissolution of polyacrylamide: good dissolving and sufficient to exert flocculation. Sometimes the need to speed up the dissolution rate, then consider the concentration of the polyacrylamide solution.

Application range:

1) As a retention aid and reinforcing agent in the papermaking process.

2) As a coagulant, flocculant and sludge dehydrating agent in water treatment.

3) As a precipitation agent and oil displacement agent in oil drilling.

4) PAM is also widely used in thickening, stabilizing colloid, drag reduction, bonding, film formation, biomedical materials and so on.

4. Inorganic flocculant aluminum sulfate

The applicable pH range is related to the hardness of the raw water. When the soft water is treated, the suitable pH is 5 to 6.6. When the hard water is treated, the suitable pH is 6.6 to 7.2, and the high-hard water is treated. The suitable pH is 7.2-7.8. The water temperature range for aluminum sulfate is 20oC to 40oC, and the coagulation effect is poor when it is lower than 10oC. Aluminum sulfate is less corrosive and easy to use, but the hydrolysis reaction is slow and requires a certain amount of alkali.

5. Inorganic flocculant ferric chloride

It is another commonly used inorganic low molecular coagulant. The product has solid dark brown crystals and a high concentration of liquid. It has the advantages of being easily soluble in water, large and heavy sputum, good sedimentation performance, wide adaptability to temperature, water quality and pH. The applicable pH range of ferric chloride is 9-11, and the formed floc has a high density and is easy to precipitate. The effect is still good at low temperature or high turbidity. Solid ferric chloride has strong water absorption, strong corrosiveness, easy corrosion equipment, high anti-corrosion requirements for dissolving and dosing equipment, irritating odor, and poor operating conditions.