To obtain a decomposition medium for treatment of organic substances which can be continuously used without exchange by mixing a foaming material in a polypropylene resin and molding the mixture into a porous hollow cylinder.
The decomposition medium 1 made of a porous resin is molded into a cylinder 3 having a hollow part 2 and specified length and thickness, and has fine holes 4 as the pores. The medium has enough hardness to prevent breaking of the shape by stirring. When the medium is to be used as sunk in water for decomposition in water, an additive to increase the specific gravity is mixed to produce the medium. In this case, an inorg. substance is added to give enough hardness to maintain its shape and to give certain specific gravity so that the obtd. medium precipitates and is convenient for the use in water. The shape and hardness can be varied according to the org. substances to be treated. When an org. substance such as raw garbage which produces bad odor during fermentation treatment is to be treated, a hollow shape which gives the max. air flow to supply oxygen is used. The hollow shape is also effective for decomposition in water which requires a large surface area.
