The physical and micro structure of volcanic rock biofilter material is characterized by rough surface and micropore, which is especially suitable for the growth and reproduction of microorganisms on its surface to form biofilm. Volcanic rock filter material can not only treat municipal wastewater, but also biochemical organic industrial wastewater, domestic drainage, micro polluted source water, etc. it can also replace quartz sand, activated carbon, anthracite as filter media in water supply treatment. At the same time, it can also do advanced treatment for the tail water after the secondary treatment process of sewage treatment plant, and the treated water can reach the reuse water standard It can be used for reclaimed water reuse.

The chemical microstructure of volcanic rock biofilter material is as follows

1. Microbial chemical stability: volcanic rock biofilter material is corrosion-resistant, inert, and does not participate in the biochemical reaction of biofilm in the environment.

2. Surface electricity and hydrophilicity: the surface of volcanic rock biofilter has a positive charge, which is conducive to the growth of microorganisms. It has strong hydrophilicity, a large amount of attached biofilm and fast speed.

3. As the carrier of biofilm, volcanic rock biofilter has no harmful and inhibitive effect on the immobilized microorganism, and it has been proved that it does not affect the activity of microorganism.

The hydraulic performance of volcanic rock biofilter is as follows

1. Porosity: the average porosity inside and outside is about 40%, and the resistance to water is small. At the same time, compared with the same kind of filter media, the amount of filter media required is less, which can also achieve the expected filtering goal.

2. Specific surface area: large specific surface area, high porosity and inert, which is conducive to the contact and growth of microorganisms, maintain more microbial biomass, and facilitate the mass transfer process of oxygen, nutrients and wastes generated in the process of microbial metabolism.

3. Filter material shape and water flow pattern: because the volcanic rock biological filter material is non pointed granular, and most of the pore diameter is larger than ceramsite, it has small resistance to water flow and saves energy consumption.