In the water treatment system using microorganisms, both anaerobic microorganisms and aerobic microorganisms can use activated carbon as a carrier and be used together. The most mature technologies currently include activated carbon anaerobic fluidized bed and biological activated carbon. The anaerobic fluidized bed reactor is suitable for the treatment of high-concentration organic wastewater. For example, the treatment effect of 1000mg/L phenol wastewater is very good. The removal rates of phenol, CODCr, and TOC can be 99%, 96%, and 97%, respectively, through activated carbon adsorption, microbial decomposition. In recent years, there has also been research on a new carrier - porous polymer carrier, although the treatment effect is slightly better than that of pure activated carbon, but its price is too high, so the activated carbon anaerobic fluidized bed method still has some application research space. Biological activated carbon refers to activated carbon with a huge specific surface area and a well-developed pore structure, which has strong adsorption characteristics for organic matter and dissolved oxygen in water. By using it as a carrier, it becomes a good place for microorganisms to gather and grow. The water treatment technology that combines the adsorption of activated carbon and the biological degradation of microorganisms under appropriate temperature and nutrient conditions is called BAC method. The BAC method is the synergistic action of activated carbon adsorption and biological degradation. The microbial activity regenerates the activated carbon, and 20% to 24% of the activated carbon can be regenerated. Therefore, biological activated carbon greatly extends the regeneration cycle of activated carbon. Meanwhile, activated carbon can also reduce the harmful effects of substances in wastewater on microorganisms. Currently, the BAC method used is mostly an aerobic activated carbon device, so to protect the good aerobic conditions in the device, ozone pre-oxidation can be used. This technology is widely used in European water treatment and has shown good treatment effects for various wastewaters.

In short, the application of activated carbon to water treatment has been greatly developed, from the beginning of a single activated carbon adsorption to the current combined application of a variety of process methods. Through the mutual promotion of synergies between two or even multiple materials, better treatment results can be achieved, and the effect of this combination is often better than the addition of various single methods. However, not all of the existing combined processes are perfect, and although some improve the removal rate of pollutants, the cost is high or the operation procedure is relatively tedious, which brings certain difficulties to the promotion of the activated carbon combined process. Therefore, the future study of activated carbon should be considered from various aspects such as high efficiency, low cost and easy operation, that is, the unity of environmental benefits and economic benefits.

With the aggravation of water pollution and the improvement of water quality standards, countries pay more attention to the in-depth study of activated carbon application methods. The combination of activated carbon and other materials is not always the ideal treatment effect, and the successful combination needs to be explored in a large number of tests. However, it is foreseeable that activated carbon, as an indispensable material in water treatment, will be more widely studied and applied.