An assembly for supporting biomass for treating sludge or wastewater
includes a first corrugated sheet having crests and valleys, a second
corrugated sheet having crests and valleys and an intermediate member
mounted between the first and second corrugated sheets. The crests have
peak surfaces and the valleys have trough surfaces. The first corrugated
sheet has a first longitudinal axis and the second corrugated sheet has a
second longitudinal axis. The corrugations of the first corrugated sheet
define a first corrugation angle of about zero degrees (0.degree.) to
about forty-five degrees (45.degree.) relative to the first longitudinal
axis and the corrugations of the second corrugated sheet define a second
corrugation angle of about zero degrees (0.degree.) to about forty-five
degrees (45.degree.) relative to the second longitudinal axis. The second
corrugated sheet is mounted to the first corrugated sheet and the
intermediate member has openings therein.