I. Introduction 
 Volcanic biological filter was first born in the United States, China once rely on imports to achieve the biological biofilm, due to its high cost, the researchers developed a bio-ceramic to replace. Today, my company researchers after the study tour in the country to find suitable processing of the mineral deposits of volcanic rock filter, after beneficiation, crushing, sieving, grinding and processing of the granular media, the main ingredients of silicon, aluminum, dozens of minerals and trace elements, calcium, sodium, magnesium, titanium, manganese, iron, nickel, cobalt and molybdenum apparent irregular particles, the color red, black and brown, porous light weight, particle size according to different requirements. 
 Second, the physical and structural characteristics 
 Volcanic biological filter performance of the physical microstructure: surface rough microporous these features particularly suitable for surface growth of microbes in their reproduction, the formation of biofilms. Volcanic media biological aerated filter can not only deal with municipal sewage, and biochemical organic industrial waste water, drainage of life, micro-polluted source water can also be replaced by quartz sand, activated carbon, anthracite as a filter media in water treatment , while the tail water in the secondary treatment process of sewage treatment plant has been advanced treatment, the treated effluent of reuse water standards for water reuse. 
 Third, the chemical structural features 
 Volcanic biological media in the micro-chemical structure as follows: a microbial chemical stability: volcanic biological filter anti-corrosion, with inert biochemical reactions involved in biofilm in the environment. 2, the surface electrical properties and hydrophilic: volcanic biological filter surface with a positive charge, is conducive to microbial growth, hydrophilic, the amount of biofilm attached fast. 3, the effects of biofilm activity: as a biofilm carrier, volcanic biological filter fixed microorganisms harmless, non-inhibitory role of Practice has proved that does not affect the activity of microorganisms. 
 Fourth, the hydraulic characteristics 
 Hydraulics aspects of the characteristics of volcanic rock biological filter in the hydraulic performance of: a porosity: inside and outside the average porosity of about 40%, water resistance, while the comparable filter, the required filter less the same to achieve the desired filtering objectives. , Specific surface area: a large surface area, the opening rate and inert contact with biofilm formation and growth of the microorganisms, more microbial biomass, microbial metabolic processes required for oxygen and nutrients and metabolic generation of waste mass transfer process. 3, the filter shape and water flow pattern: volcanic biological filter is not sharp granular, and the aperture most than ceramsite large, so use small flow resistance, saving energy consumption. 
 Five, the average the volcanic biological filter in the physical performance test parameters are as follows 


 Performance unit test results of the unit test results of performance indicators 
 Bulk density Kg/m3 740 specific surface area m2 / g, 13.6-25.5 
 The proportion of 1:1.29 compressive strength Mpa 5.78 
 Moisture content% 0.9-1.0 anti-shear strength Mpa 3.98 
 Porosity% 73-82 friction loss% <1 
 More than 80 of the removal of organic matter%, biofilm time hours and 27 
 More than 85% of the COD removal rate of hydrochloric acid soluble% <1.0 
 BOD removal efficiency of 75-93% leachables micro contain beneficial minerals and trace elements 
 In addition to the full appearance of more than 85% of ammonia, nitrogen particles, similar to the globular 
 Six, the chemical composition of volcanic biological filter 

 Chemical composition of SiO2 of CaO of MgO Fe2O3 Al2O3 
 Content% 43.27 9.86 1.49 11.86 14.71