Serigraph Uses Biological Filters to Cleanse the Air

To cleanse the air of pollutants from its printing plant, Serigraph Inc. first turned to horse manure. The West Bend (WI) printer set up a biological filter for removing volatile organic compounds from the air before it was released from the plant. The filter used horse manure as the medium to grow bacteria that devoured the pollutants. Not just any horse manure. It came from Florida, because Wisconsin horse manure had the wrong pH for growing the bacteria.

Much less smelly, tree bark is now used for Serigraph's biological filter, which is housed in two 30-by-60-foot chambers.