IPC Definitions - January 01, 2012
C02F 9/00 - Definition
This main group covers:
Only those combined water, waste water or sewage treating operations where the essential characteristic resides in the combination of the treatment steps.
Special rules of classification
In this group, in the absence of an indication to the contrary, classification is made in the last appropriate place.
Any individual step of a multistep treatment, which is not identified by the classification in the last appropriate place, and which is considered to represent information of interest for search, may also be classified in one or more of groups C02F 1/00-C02F 1/56 or C02F 1/66-C02F 7/00. This can, for example, be the case which it is considered of interest to enable searching of multistep treatments using a combination of classification symbols. Such non-obligatory classification should be given as "additional information".
Treatments where the essential characteristic resides in an individual step of the treatment, which treatments are covered by groups C02F 1/00-C02F 7/00, are not covered by group C02F 9/00. An example of such treatments is a treatment in which the essential characteristic resides in a chemical treatment step and in which the one or more other steps, such as filtration or settlement, are conventional.