Recirculating Aquaculture Carbon Dioxide Control Degassing Column Sizing

Degassing column functions:
Strip nitrogen, carbon dioxide, hydrogen sulfide and other supersaturated gases from water
Increase dissolved oxygen in subsaturated water
Oxidize ammonia ("trickling biofilter")

We can build degassing columns to handle virtually any water flowrate and achieve your water quality requirements. Our computer programs make short work of complex nitrification and heat and gas transfer calculations so you get the system you need and don't pay extra for oversized equipment. We can configure the column to meet your space requirements. These units are equipped with fan-type blowers that move air upward through the down-flowing water. This "counter flow" design greatly increases gas transfer rates. Based on your water quality, we'll recommend the best media for gas removal and fouling resistance. All of our degassers feature easy media removal. Please refer to Tech Talk 33 ("Removing Carbon Dioxide") for application guidance.

This questionnaire is for customers wishing to remove CO2 by adding a degassing column to their recirculation water flow. It is applicable to tank systems having uniform water quality throughout ("completely mixed reactors") and is not useful for raceway systems with plug flow characteristics. For flow-through raceway systems with no recirculation, use the "Sourcewater Degasser" questionnaire.

Recirculating systems that use pure oxygen rather than air usually have a high fish density and require CO2 degassing equipment. The required water flowrate through the CO2 degasser is generally similar to water flowrate requirements for pure oxygen injection and for ammonia and suspended solids control. Suspended solids should be removed from the recirculating water prior to entering the CO2 stripper. This prevents clogging and biofouling. Although degassing columns can also be used for ammonia removal (trickling biofilters), hydraulic loading rates (gpm/sq.ft.) are an order of magnitude lower than for CO2 degassing. The best place for degassing is after the biofilter, where the CO2 concentration is highest.

The degassing column custom sizing and design service includes summary printouts of key questionnaire inputs (customer supplied), a description of the column we recommend, and a price quotation. There is a prepay fee for this service.

Call 407-886-3939 if you have questions or need additional information.