Manufacturing Facility, Tucker, Georgia

Challenge

The client was experiencing volatile organic compound (VOC) emissions from its processing operations. The primary contaminants of concern were acetic acid, ethanol and propylene glycol. The required overall removal efficiency of the biofilter system is 95 percent.

Solution

Envirogen Technologies, Inc.’s (Envirogen’s) Built-in-Place biofiltration system, designed to treat 85,000 standard cubic feet per minute (scfm) of air, was installed at the facility in 2003. The project involved the design, specification, manufacture, material and equipment supply, and startup support of the biofilter system.

Particulate matter is removed prior to contact with the biofilter media, which is composed of 22,500 cubic feet of pre-composted wood bark arranged in three bays.  Contaminated air from the facility is pushed through a humidification chamber using two centrifugal blowers.  The humidified air then passes into three sloped plenum chambers, where the air is evenly distributed, and then flows upward through the moistened biofilter media.  As the air passes upward through the media, the target contaminants are absorbed into the media and are degraded.  The cleaned air exits the top of the media in each chamber and is discharged from the system through exit tunnels to a common stack.

The biofilter system performance test was conducted in October 2003, shortly after system start-up.  Propylene glycol and ethanol, which make up 80 percent of the total VOC emissions from the facility, were sampled in order to verify that the performance requirements of the system were being met.  Emissions were tested at three operating conditions over a two-day period.  The propylene glycol removal efficiency was greater than 99 percent under all conditions tested.  The average ethanol removal efficiency was 91 percent and the combined VOC control efficiency was approximately 95 percent as required.