Discriminant index of MBBR filler
1. Adhesion of biofilm
Biofilm adhesion capacity - the most important indicator for evaluating the quality of fillers Biofouling amount = protected surface area (related to the design and operating state structure of the filler) × biofouling amount per unit surface area (related to the performance of the filler)
2. Filler performance
Filler performance - the most important indicator for evaluating the biofouling capacity of fillers
(1) Surface properties of fillers
1. Surface structure: It is generally believed that the surface roughness is large and the film hanging speed is fast.
2. Surface potential: Generally, microorganisms are negatively charged, and the surface of the filler is positively charged, which is suitable for microbial growth.
3. Hydrophilicity: Microorganisms are hydrophilic particles, and the filler is hydrophilic and suitable for microbial growth and filming.
(2) Hydraulic performance
1. Porosity: The volume occupied by the filler, the porosity is high.
2. Shape and size: affect the flow state of water flow and airflow.
(3) Fluidization properties: related to the density of the filler. The density of the filler should be 0.97-1.03, and fluidization can be achieved with minor aeration or agitation.
3. Judgment of film-hanging maturity
Judgment by the naked eye:
The biofilm is evenly distributed on the surface of the carrier, and the closer it is to the surface of the carrier, the denser it is, otherwise, the looser it becomes.
Microscopic judgment:
The biofilm has a dense structure and diverse types of microorganisms. The number of sessile ciliates, bellworms, and branch worms is mostly, and the appearance of a small number of rotifers and swimming ciliates marks the maturity of the biofilm.