AIR IONIZATION FOR ODOR CONTROL AT WASTEWATER TREATMENT FACILITIES: FULL-SCALE PERFORMANCE DATA

Polarized air ionizers produce positively and negatively charged oxygen molecules, or ions, with no ozone generated. The ionized air effectively oxidizes most air contaminants including hydrogen sulfide, ammonia, and other organic gases. This Swiss technology (Bentax-Air-Tec) has been successfully applied at wastewater facilities in Europe for twenty years. In addition to providing odor control and a safe work environment, air ionization prevents corrosion of electronics and equipment. Systems employing this technology have now been applied by Trans-Tech at many installations in the United States, and performance information has been obtained from some of these full-scale operations.Small portable ionizer modules can be installed as self contained recirculation units complete with fan. Alternately, the modules can be installed in ductwork on the fresh air supply side of an existing ventilation system. Each duct mounted model 50F5 ionizer is 64 × 22 × 21 cm (25 × 8.8 × 8.4 in) and weighs only 7.3 kg (16 lb.) The number of modules required depends on both the volume of air treated and the contaminant concentration. Typically, two modules will treat a 7.6 m (25 ft) diameter sludge storage tank, while a large belt filter press room with several presses may require a dozen or more modules.Operating installations at wastewater facilities in the United States include lift stations, belt filter press rooms and sludge holding tanks. Facilities providing full scale system data include; the Metro Wastewater Reclamation District (MWRD), Denver, CO, San Jacinto River Authority, near Houston, TX, and the Three Rivers WWTP, Three Rivers, MI. Based on the full-scale performance data from the facilities presented, air-ionization has been demonstrated to be a reliable and cost-effective means of odor control. The system has a minimal footprint and low power requirements of 35 watts per module. The system has zero water usage and no chemical handling or storage. Both capital and operating costs were found to be less than other options such as wet scrubbers, activated carbon, and biological treatment.