Biological contact oxidation process is a biological magic process between 
activated sludge process and biological pond, which is characterized by setting 
fillers in the pond, aerating the bottom of the pond to fill the sewage, and 
making the sewage in the pond in a flowing state, so as to ensure full contact 
between the sewage and the fillers in the sewage and avoid the defect of uneven 
contact between the sewage and the fillers in the biological contact oxidation 
pond. The basic principle of purifying wastewater is the same as that of general 
biofilm process, which uses biological adsorption of organic matter in 
wastewater.
