characterised by the animals or plants used, e.g. algae [3]
3
/
34
•
characterised by the micro-organisms used [3]
5
/
00
Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents (softening using ion-exchange C 02 F 1/42) [3]
5
/
02
•
Softening water by precipitation of the hardness [3]
5
/
04
•
•
using phosphates (C 02 F 5/06 takes precedence) [3]
5
/
06
•
•
using calcium compounds [3]
5
/
08
•
Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents [3]
5
/
10
•
•
using organic substances [3]
5
/
12
•
•
•
containing nitrogen (C 02 F 5/14 takes precedence) [3]
5
/
14
•
•
•
containing phosphorus [3]
7
/
00
Aeration of stretches of water [3]
9
/
00
Multistage treatment of water, waste water or sewage [3]
Notes
(1)
This group covers only those combined treating operations where the interest is directed to the relationship between the steps. [3]
(2)
This group does not cover, for example, chemical treatment followed by settlement or biological treatment involving normal mechanical treatment. [3]
11
/
00
Treatment of sludge; Devices therefor [3]
11
/
02
•
Biological treatment [3]
11
/
04
•
•
Anaerobic treatment; Production of methane by such processes [3]
11
/
06
•
by oxidation (incinerators or other apparatus for burning waste liquors, e.g. sulfite liquor from paper-making plant, F 23 G 7/04) [3]
11
/
08
•
•
Wet air oxidation [3]
11
/
10
•
by pyrolysis [3]
11
/
12
•
by de-watering, drying, or thickening [3]
11
/
14
•
•
with addition of chemical agents [3]
11
/
16
•
•
using drying or composting beds [3]
11
/
18
•
by thermal conditioning (by pyrolysis C 02 F 11/10) [3]
