Moving Bed Biofilm Reactor (MBBR) has built thousands of sewage (waste) water treatment facilities in many countries in the world and achieved good treatment effect. Using the basic principle of biofilm method and the advantages of activated sludge method, MBBR process USES suspension filler as the carrier of microbial growth and fully fluidized in the secondary biochemical tank to achieve efficient sewage treatment.

 Operating principle

Moving Bed Biofilm Reactor (MBBR) requires a suspension filler with a specific gravity close to water, a large effective specific surface area, and suitable for microbial adhesion and growth. The suspended filler can be suspended by slight stirring in the biochemical tank, which is easy to move freely with the water and can form a good fluidized state.

Under aerobic conditions, the rising buoyancy of air bubbles generated during aeration and oxygenation can push the packing and the surrounding water to flow. When the airflow passes through the water flow and the filler gap, it is blocked by the packing and divided into small bubbles.

In this process, the filler is sufficiently stirred and mixed with the water flow, while the air flow is sufficiently divided into small bubbles, increasing the contact and oxygen transfer efficiency of the biofilm. Under anaerobic conditions, the water flow and packing are fully fluidized under the action of the submersible stirrer to achieve the purpose of degradation of the biofilm in full contact with the treated pollutant.

The core of MBBR process is to realize the full fluidization of suspended carrier filler to achieve the purpose of strengthening the treatment of pollutants. In the practical application of MBBR process, the main factors to be considered include biochemical pool type, amount of suspended packing, aeration system, interception screen, propeller, etc.

Fluidization of biological filler in aeration zone is the key to achieve good processing function of the system. It mainly depends on the aerobic aeration system of the biochemical pool. An appropriate aeration system in the aerobic zone can ensure the fluidization effect of the biological carrier fluidized filler, ensure the fluidized filler to flow up and down in the water, make the filler and sewage fully mix, collision, contact, effectively complete the contact, exchange, adsorption and other processes of the three directions of pollutants, water and gas.

 Packing proportion generally choose 0.94 0.97, during the period of bacteria culture, packing slowly to a large number of biofilm on the surface, adhesion amount, the greater the proportion of increase gradually, when the biofilm on the packing materials to a certain thickness, its density is greater than 1, the packing from the aeration zone sank to the bottom of the tank, aeration zone at the bottom of the strongest impact, can quickly wash away the remnants of biofilm on the packing, after take off the film packing weight is reduced to below 1, and in the aeration zone.

 According to the characteristics of specific gravity change before and after hanging the film, the filler can be agitated in the aerated zone and non-aerated zone with the water flow, thus completing the growth and shedding process of the biofilm alternately, ensuring the quantity stability and activity of the biofilm, and making the process run more stable. In order to prevent the fluidized suspended packing from entering the next stage with the mixture, the suitable position in the aerobic zone is designed with the screen for simple interception and separation. The screen is made of stainless steel, which is matched with suspension packing.