Solids or viscous wastes. Any solid or viscous material
which could cause an obstruction to flow in the POTW resulting in
interference. Included as examples of such materials, but without
limiting the generality of the foregoing, are significant proportions
of ashes, wax, paraffin, cinders, sand, mud, straw, shavings, methyl,
glass, rags, lint, feathers, tars, plastics, wood and slurries, beer
and distillery slops, grain processing wastes, grinding compounds,
acetylene generation sludge, chemical residues, acid residues, food
processing bulk solids, snow, ice and all other solid objects, material,
refuse and debris not normally contained in sewage, any solid exceeding
one inch in any dimension.