Seventy percent of our planet is covered by sea water. So the earth is called water ball. How to make full use of the existing water resources to achieve seawater desalination is a problem that human beings have been exploring and improving. With the continuous improvement of human science and technology, there have been many different ways of water treatment in this society. Physical treatment, chemical treatment, biological treatment are common methods, such as MBBR, SBR, biological aeration, biofilm treatment, etc.