REDUCING CAPITAL COSTS BY VARYING ODOR CONTROL SYSTEM VELOCITY

Odor control equipment is important to the wastewater industry throughout the world. It allows
wastewater plants and collection systems to operate with minimal impact on the surrounding
regions. One very prominent technology is engineered dry-scrubbing media. This media
consists of various base materials formed into spherical media through the processes of
agglomeration and impregnation. The base materials include adsorbents such as activated
alumina, activated carbon, and sodium bicarbonate. The liquid impregnants include potassium
permanganate, sodium permanganate, and potassium hydroxide. These materials combine to
form an engineered media having physical and chemical properties that allow contact with and
removal of odorous gases.
This paper focuses on reducing capital cost by increasing the velocity of air through an odor
control system. In the past, odor control systems performed well at face velocities of 60-100 feet
per minute (fpm) across a media bed. Experience and performance tests on installed systems
confirm this. In the examples sited here, systems have achieved acceptable life times as well as
efficiencies greater than 99.5%.
The efficacy of an air velocity increase depends on the following parameters: gas mass transfer
zone, media pressure drop, capital cost reduction, and energy consumption. These factors point
toward 125 fpm as the optimum velocity-increase point. The scrubber is also capable of
operating at 150 fpm with higher energy consumption. Wastewater plants can use these results
to evaluate scrubber options and meet budgetary constraints.