How to treat oilfield wastewater with polyacrylamide

Oilfield wastewater is produced in the process of oil exploitation and processing, which contains a large amount of organic substances and heavy metals, causing great harm to the environment and ecology. Therefore, the treatment of oilfield wastewater is very important. Polyacrylamide is a commonly used precipitator, which can effectively remove organic substances and heavy metals in oilfield wastewater. Next, we will introduce the treatment methods of polyacrylamide in detail.

1.Introduction of Polyacrylamide

Polyacrylamide is a water-soluble polymer with high molecular weight, which is formed by polymerization of acrylamide monomer. Its molecular weight ranges from tens of thousands to millions, and different molecular weights can be selected according to needs. Polyacrylamide has excellent sedimentation, filtration and coagulation properties. It can rapidly precipitate and agglomerate small particles and colloidal substances suspended in water into large particles for easy filtration and treatment.

2.Principle of oilfield wastewater treatment

Oil, amino acid, fatty acid, styrene, phenol, heavy metal and other organic and inorganic substances are mainly contained in oilfield wastewater. Polyacrylamide combines with these substances in oilfield wastewater to form polymer complex, which can agglomerate into large particles and precipitate, thus achieving the purpose of purifying water quality.

3.Treatment method of polyacrylamide

⑴ Prepare polyacrylamide solution

The configuration of polyacrylamide shall be based on the principle of using it as it is prepared. It shall be dissolved with clean water. A certain proportion of clean water shall be injected into the dissolution tank to start mixing, and then the dry powder of polyacrylamide shall be evenly and slowly added into the water for dissolution. When using the polyacrylamide solution, the concentration shall be adjusted reasonably, and then added into the oilfield wastewater for treatment.

⑵ Adjust the pH value of oilfield wastewater

The pH value of oilfield wastewater is generally acidic, which is not conducive to the use of polyacrylamide, so it needs to be adjusted to neutral or alkaline. Alkaline substances such as sodium hydroxide can be used for adjustment.

⑶ Add polyacrylamide

When the prepared polyacrylamide is added to the oilfield wastewater with adjusted pH value, the method of stirring or flocculation is generally adopted to promote the sedimentation and coagulation of suspended particles and colloidal substances.

⑷ Separation and filtration

After the oilfield wastewater is coagulated and precipitated with polyacrylamide, the supernatant and precipitate are separated by gravity sedimentation or centrifugation. Then, the sediment is further filtered and dehydrated to obtain the treated water.

To sum up, polyacrylamide is an effective oilfield wastewater treatment agent, which can remove suspended particles and colloidal substances, organic substances and heavy metals. The application of polyacrylamide in oilfield wastewater treatment can significantly improve wastewater quality, reduce environmental pollution and promote the sustainable development of petroleum industry.