Application of microbial flocculants in sewage treatment

College of Resoueces and Environment, Southwest University, Chongqing, China

Abstract

At present, sewage from agriculture, industry and urban life has become the three major sources of sewage today. As global wastewater emissions continue to increase, people are trying to find more effective solutions. Among them, flocculation technology is widely favored as a more economical and simple one among many water treatment technologies. Inorganic and organic polymer flocculants are two types of chemical flocculants developed and applied in China for a long time. Both types of flocculants have their own advantages in different fields. However, in the process of using these two types of sewage treatment technology, it will bring many adverse effects on human health and ecological environment. Inorganic flocculants have a fast flocculation speed, and have a high specific gravity of alum flowers, and they are easy to sink, but they will bring a large amount of inorganic ions such as aluminum and iron into the treated liquid, and excessive intake of aluminum ions by the human body may cause dementia A series of diseases. Strong corrosiveness is the biggest problem of iron salt flocculants in use. It will shorten the service life of the equipment and bring color to the treated water. Organic polymer flocculant flocculates faster than inorganic flocculant, and has more advantages in terms of dosage, separation process, adaptability, etc., because some polymer flocculants monomer itself is toxic, even its hydrolysis or degradation the product is also toxic (such as polyacrylamide monomer). Therefore, researchers are committed to finding efficient, safe, and non-polluting flocculants to meet the requirements for safe use of flocculants and the reduction of secondary pollution during wastewater treatment. Compared with chemical flocculants, the outstanding advantages have caused the rapid development of microbial flocculants, and its outstanding advantages without secondary pollution have attracted the attention of many researchers, and the development prospect is broad.