The Use of Inorganic Packing Materials during Methane Biofiltration

Table 1

Characteristics of the tested packing materials.

	PM1	PM2	PM3
	(expanded clay—7 mm)	(rock—5 mm)	(rock—2 mm)
Density (kg/m^3)	750	1200	2850
External specific surface area (m^2 packing external surface/m^3 of biofilter)	470	1250	1360
Void fraction in the biofilter	0.55	0.40	0.37
Water holding capacity (Vol. water/Vol. material)	0.15	0.07	0.10