How does MBBR biological filler hang film effectively and quickly？

How does MBBR biological filler hang film effectively and quickly

Since the founding of New China, the total amount of water resource in our country has shown a downward trend along with the sustained and rapid development of Chinese economy and the unceasing process of urbanization and industrialization. According to the forecast of the Ministry of Water Resources, by 2030, China's population will increase to 1.6 billion, the per capita water resources will be reduced to 1,760 cubic meters, and the total water shortage will reach 40 to 50 billion cubic meters, reaching the world recognized water shortage warning line.

The state attaches more and more importance to sustainable development. In the future, it will continue to strengthen the protection and management of water resources, and vigorously guide and encourage investment in environmental pollution control. At present, many new sewage treatment projects and upgrading projects are increasing. Among them, MBBR process is also gradually emerging, which is favored by many engineering designers and applied, becoming one of the international mainstream processes. In the actual application of MBBR process project, often hear a lot of friends who just tried the process say that the filler is difficult to hang film, hang film and so on. MBBR biological filler is very different from the commonly used fixed bed filler. There are many factors affecting whether it can quickly and effectively hang the film. For example, the quality of packing, PH value, temperature, and the size of aeration can affect the film hanging speed and effect.

Packing stage
1. When the filler is added, observe whether there is accumulation phenomenon, and stop putting once accumulation occurs. Wait until the next day to continue the observation before adding.
2. Intermittent aeration and sustainable aeration at night are adopted when the filler is put in, but the aeration volume needs to be reduced.
3. After 24 hours of operation, water is continuously injected for 2-3 hours, and then aeration is continued. After 48 hours of operation, observe the film hanging condition on the packing, increase the water intake to extend the water intake time, and check the dissolved oxygen condition in the tank, which is preferably kept at about 1.5-2.0mg/L. After 72 hours of operation, contact the inlet water and gradually add it to the design requirements. According to the routine inspection of the water quality of the inlet and outlet on duty, it is expected that the design water quality requirements can be reached in about 7 days.

The culture stage of a biofilm
The so-called culture of biofilm is to generate and accumulate a certain amount of microorganisms in the treatment system and make the biofilm on the filler reach a certain thickness through certain means. The culture methods mainly include static culture and dynamic culture.
1. Static culture
After 6 days of closed aeration culture, a thin layer of yellowish brown biofilm had grown on the surface of the filler. Therefore, continuous water intake was used for dynamic culture, and the water intake was adjusted to control the dissolved oxygen between 2 and 4mg/L (dissolved oxygen was measured by dissolved oxygen meter). About 15 days later, there were some amoeba and wanderworms on the packing (observed with a biological microscope), and the packing was sticky and greasy. Protozoa such as flagellates, bellworms and paramecium free bacteria appeared 20 days later. After 20 days of culture, metazoa such as rotifers and nematodes appeared, indicating that the biofilm had grown. Continuous industrial operation can begin.
2. Dynamic culture
After 6 days of closed aeration culture, a thin layer of yellowish brown biofilm had grown on the surface of the filler. Therefore, continuous water intake was used for dynamic culture, and the water intake was adjusted to control the dissolved oxygen between 2 and 4mg/L (dissolved oxygen was measured by dissolved oxygen meter). About 15 days later, there were some amoeba and wanderworms on the packing (observed with a biological microscope), and the packing was sticky and greasy. Protozoa such as flagellates, bellworms and paramecium free bacteria appeared 20 days later. After 20 days of culture, metazoa such as rotifers and nematodes appeared, indicating that the biofilm had grown. Continuous industrial operation can begin.

The acclimation stage of biofilms
The purpose of domestication is to select microorganisms that adapt to the actual water quality and eliminate useless microorganisms. For the treatment technology with the function of denitrification and phosphorus removal, nitrobacteria, denitrifying bacteria and phosphorus accumulating bacteria become the dominant bacteria group through domestication. The specific approach is to first maintain the normal operation of the process, and then, strictly control the process control parameters, DO average should be controlled between 2~3mg/l, aerobic tank aeration time is not less than 5 hours, in this process, do a good job of the water quality indicators and control parameters every day, when the average thickness of the biofilm in 0.2-0.5mm or so biofilm culture is successful, Until BOD5, SS, CODCr and other indicators meet the design requirements.

Selection of MBBR biological fillers
1. Material
MBBR process is a one-time addition, no need to replace the biological filler of the new process, so the material requirements are very high, generally choose high purity HDPE material of biological filler life can reach more than 15 years. If the use of inferior material, it is easy to use in the later project, leading to the biological filler fragmentation, blocking the pipeline.
2. Production technology level
Biological filler through the fluid mechanics design of geometric structure, generally cylindrical porous, in the production engineering of the production of the production technology is very high requirements, from the development of the mold to the professional production machine and production process of temperature, speed debugging are very important. For example, some biological fillers with uneven wall thickness are easy to lack toughness.
3. Specific surface area
The specific surface area of biological filler directly affects the number of microorganisms cultured in the unit cubic water body, and the more the number of microorganisms cultured, the stronger the sewage treatment capacity. However, in the actual selection of filler, not only the specific surface area of biological filler, but also the diameter and pore size of the filler should be considered. The diameter of the filler is related to the aperture of the intercepting net. The pore size of the filler will not only affect the size of the specific surface area, but also affect whether the aging biofilm is easy to fall off. At present, some MBBR biological fillers on the market have a large specific surface area, but the pores are small, and the post-treatment effect of the early hanging film is very good. However, after one or two years of actual operation, the aging biofilm can not fall off, resulting in the later water quality cannot reach the standard.