BioScrub Process Proves Mettle at Formaldehyde VOC Removal
Updated: Aug 28
Formaldehyde is used in numerous types of process industries throughout the world such as fabric manufacturing, manufactured wood products, and roofing materials. Enormous quantities of formaldehyde are released to the atmosphere by these industries every day. Indeed, formaldehyde emissions from process industries and their control have become an increasingly important issue during the past several years.
Formaldehyde is classified as a VOC and is one of many such compounds that, when released into the atmosphere, can react photo-chemically with oxides of nitrogen to form smog and ozone. Thus industry is seeking more efficient and cost-effective alternatives to traditional incineration technologies for use on their VOC laden process exhausts.
The common methods for controlling formaldehyde emissions are through some form of oxidation process-using thermal, regenerative, or catalytic oxidizers. Due to the dilute nature of a typical process stream where formaldehyde concentrations are less than the lower flammable limit, incineration requires the consumption of large quantities of fuel to support the combustion and maintain the required temperature for the desired degree of destruction. Incineration of such dilute streams using supplemental fuel produces unnecessarily large quantities CO2.
CMS Group Inc. has developed an alternative technology, the patented BioScrub process, which removes the contaminants from the gas stream and subsequently destroys them through biodegradation.
CMS set up a pilot-scale BioScrub system to treat exhaust from the curing oven at a roofing-materials plant. A quench unit was installed to cool the gases from 220″F to less than 110″F. Throughout the pilot study the unit consistently decreased the inlet concentration of up to 82.5 ppm of formaldehyde to 0 ppm at the outlet.
Analysis of both the air and water at several points across the unit showed that the air concentrations were reduced to 0 ppm after the second stage, indicating that the unit was not exceeding its mass transfer limits based on available surface area. Water analysis across the stages revealed a very fast rate of biodegradation, and a subsequent mass balance indicated an overall conversion of greater than 99.5% of the incoming formaldehyde to carbon dioxide and water by the third stage.
The pilot study showed that the BioScrub process, when treating formaldehyde emissions,
does so at lower capital and operating costs than other technologies;
is self-regulating and requires little operator interference;
has a small footprint with respect to alternative forms of biological gas-cleaning technologies;
does not produce excessive amounts of carbon dioxide; and
operates at ambient temperatures, eliminating the possibility of back-drafts and explosions.
EES Update 8/04
The promises made during the original BioScrub pilot study proved true. CMS patented their product and it is now used in not only the removal of formaldehyde, but also BOD, metals, other VOCs and hydrocarbons. CMS is now owned by Seprotech Systems Incorporated who also owns the BioscrubTM patent.
(The above article was reprinted with permission of Pollution Online (11/2/99)