Method |
Design Criteria |
Advantages / Disadvantages |
Degassing |
Cross sectional area of degasser:
2 x (0.0001
x lpm) / 3.14))-2
Height 1.5m
The
air suction rate through the degasser should be at least 20% of the
water flow rate. |
Off gas requires to be either vented away from staffed
areas or should be treated.
Can result in high pumping costs.
Can be used as an integral part of trickle filter or carbon
dioxide degasser if used within a system.
Will increase oxygen concentrations to approx 85 - 95%
saturated
|
Chemical dosing |
Dosing with sodium thiosulphate at 2mg/l
to reduce each 1 mg/l ozone. This is very dependant however on
oxygen content of water as the thiosulphate will also be used up
reducing this. |
Costly to install and operate correctly.
May result in removal of some oxygen from water
Unknown effects of excessive thiosulphate on fish stocks
|
Activated carbon |
1g of carbon will remove 6g ozone,
however allowance must be made for the carbon being used up with
other chemicals that it will remove. Attention to water quality is
therefore important. |
Expensive systems not really suited to
aquaculture
Costly replacement of carbon
High operating costs through pumping through carbon beds.
|
Ultra violet light |
150,000
mW
cm2 for 13 seconds to reduce 0.5 - 1.5 mg/l
O3 to safe levels |
Very dependant on constant water clarity
/ quality for effectiveness.
Expensive to install but relatively cheapo to run thereafter.
Added benefits of disinfection of the water.
|