H&T uses the packed tower forced draft degasifier design to strip CO2, VOCs and other gases. The towers are circular and of FRP construction. They can be supplied with an integral FRP clearwell or can sit above an existing below-grade clearwell. A polypropylene packing is used in the tower. Various sizes and shapes are available and selection would depend on job-specific requirements. Influent water is sprayed on the packing at the top of the tower and, as the water cascades down through the packing, it forms a film on the surface of the packing, facilitating the release of entrained gases into the counter-current flow of air passing up through the tower. A low-pressure, high-volume fan pushes air up through the tower and a demister removes water droplets from the air, which exit the tower through a vent. Performance is dependent on the water temperature and concentration of gases. The depth of packing, size and type of packing and air volume can all be adjusted to meet any requirements.
Forced Draft Degasifier installed at Alcorn (tank on the very top of the picture)