Fish pond aerator is a method of severely contacting air and water, with the aim of dissolving oxygen in the air into water or dissolving unwanted gases in water.
The double membrane theory holds that there are gas and liquid films at the gas water interface, and air and liquid flow outside the gas and liquid films, in a turbulent state. There is laminar flow between the gas film and liquid film, without convection, and under certain conditions, pressure and concentration gradients occur. There are two main types of aeration: air blowing aeration and mechanical aeration. Blast aeration is an aeration method that uses an aeration blower, aerator, diffuser plate or diffuser tube to introduce bubbles into water. This method is commonly used in sewage treatment. Mechanical aeration refers to the aeration method that uses impellers and other instruments to introduce bubbles. All aeration equipment must meet the following three functions: maintaining effective gas water contact, and maintaining a certain oxygen concentration in the water while biological oxidation continuously consumes oxygen. Generate sufficient mixing and water circulation within the aeration zone, maintain sufficient liquid velocity, and suspend biological solids in the water in the air. For biological aeration equipment, if the concentration of organic matter is too high or there is too much residual microbial film on the filter layer, partial anaerobic metabolism will occur inside the filter layer, leading to abnormalities. The solution is as follows: reduce the accumulation of microbial membranes in the aeration equipment, allow the biofilm to detach normally, and discharge it out of the tank through backwashing to ensure the normal operation of the aeration facilities and avoid the impact of high concentration or high load sewage. The biofilm is severely detached, and abnormal detachment of the biofilm is not allowed during normal operation of the aeration equipment. The main reason for producing a large amount of biofilm detachment is due to water quality reasons (such as high concentrations of inhibitory or toxic pollutants or sudden changes in acidity). The solution is to improve the water quality so that the water entering the aeration equipment is basically stable.
The treatment efficiency of fish pond aerators is low. If the aeration system is working normally and the growth of microbial membranes is good, the treatment efficiency will decrease. Usually, it is not caused by rapid changes in water quality or the inflow of toxic pollutants, but by the acidity, dissolved oxygen, water temperature, and short-term overload operation of the incoming water. For this phenomenon, as long as the degree of decrease in treatment efficiency does not affect the standard discharge of water quality, no measures will be taken, and it will return to normal after a period of time. If the water quality affects the standard discharge, some local adjustment measures should be taken, including adjusting the acid value of the inlet water, adjusting the gas supply, reactor insulation, inlet water heating, etc. When the pollution blocking ability of the aeration equipment decreases and backwashing is normal, only the pollution blocking ability of the aeration equipment decreases. This may be due to poor pretreatment effect and high carbon dioxide concentration in the water. At this time, it is necessary to strengthen the operation and management of the pretreatment facilities. The inflow water quality is abnormal and the inflow concentration is high. In this case, it is necessary to increase the aeration amount and aeration time to maintain the stability of the sludge load. This situation of low inflow concentration mainly occurs in rainstorm weather, which needs to be solved by reducing the aeration force and time. The abnormal water quality, mud and turbidity in the effluent are mainly caused by thick biofilm thickness, strong backwashing intensity or too many backwashing times, microbial loss, and decreased treatment efficiency. The solution is to increase the aeration rate and increase the dissolved oxygen content. The local water distribution system is obstructed, which may lead to insufficient local oxygen. The solution is to rectify or increase the recoil intensity. The main reason for the slight yellow color of the water is that the amount of chemical phosphorus removal in the biological aeration equipment is too much, and the iron salt exceeds the standard. Reducing the amount of chemical phosphorus removal is sufficient.
