The Free Online Aquaculture Dictionary 
Degassing devices Type Design criteria 
Degassing required 
Type 
Design
criteria 
Merits

Carbon dioxide 
Aeration 
Medium or coarse bubbles, 25m^{3} / hour
air flow rate, distributed as evenly as possible across 1m^{2}
cross sectional area, 0.75m deep, for a flow rate of 3000 lpm 
No head loss, can therefore be included easier into
gravity systems. Not generally as efficient as packed column degassing
(below) 
Carbon dioxide 
Atmospheric pressure 
Air flow rate required = 2 x water flow rate. Water
flow rate = 55 litres per second per m^{2} cross sectional area of
the column/tank (assumes 1.5m high degasser and media surface area of 100
 200m^{2}m^{3}) 
Very efficient. Additional cost of pumping to top
of degasser increases operational costs. Higher capital costs 
Nitrogen 
100 to 150 mbar gas vacuum 
Air flow rate required = 0.25 x water flow rate.
Water flow rate = 25 litres per second per m^{2} cross sectional
area of the column/tank. 
Higher capital costs die to reinforcement of vessel
structure due to vacuum. No other effective alternative. 