When usingmagnetic separationtechnology to treat wastewater, the particles in the wastewater must possess a certain degree of magnetism. Therefore, this technology is widely applied in the steel industry, such as in the treatment of wastewater from hot rolling, continuous casting, and cold rolling emulsions, where over 98% of the pollutants are strongly magnetic substances. Additionally, it contains some oils and a small amount of non-magnetic substances, making it highly suitable for purification using magnetic separation. Biyuan Environmental Protection believes that this method is simple to operate, requires a small footprint, and delivers effective treatment results.

In recent years, high-gradient magnetic separation technology has been widely used in the treatment of steel industry wastewater. This new type of magnetic separator is composed of steel wool-like micro-sized magnetic media combined with iron-clad coils. Since its introduction, it has brought significant changes to traditional magnetic separation devices with its advantages of miniaturization, high efficiency, cost savings, low operating expenses, simplicity of operation, large processing capacity, and scalability. As a result, it is widely used in industries such as steel and wastewater treatment.

For wastewater containing non-magnetic or weakly magnetic pollutants, the method of adding magnetic seeds is generally adopted. This involves combining non-magnetic substances with magnetic seeds, followed by the use of magnetic separation technology or a combination of flocculation sedimentation and high-gradient magnetic separation technology to purify the wastewater. This method is referred to as "magnetic seed coagulation magnetic separation" or "magnetic loading magnetic separation." There are no selective requirements for magnetic seeds in the field of wastewater treatment; generally, they only need to: ① exhibit strong magnetism; ② be easily recyclable and reusable.

Most urban wastewater is non-magnetic. By adding magnetic mixtures and appropriate coagulants, followed by treatment with a high-gradient magnetic separator, suspended solids, color, turbidity, phosphates, bacteria, and other contaminants can be removed. Researchers at the Massachusetts Institute of Technology achieved excellent results by adding Fe3O4 and aluminum to urban wastewater and treating it with high-gradient magnetic separation. However, this technology is not fundamentally different from coagulation sedimentation; it merely replaces gravity sedimentation with magnetic separation, and its ammonia nitrogen removal efficiency is relatively low.

Biyuan Environmental Protection suggests that to effectively treat pollutants such as COD, BOD, ammonia nitrogen, and phosphorus in wastewater, magnetic separation technology must be combined with existing biological treatment technologies to achieve better results. For example, the BioMag process, which combines CoMagTM with activated sludge, can achieve nitrogen and phosphorus removal. Its essence lies in biological treatment combined with chemical phosphorus removal through dosing. Phosphorus removal is primarily achieved through chemical precipitation and coagulation magnetic separation.